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Kai Klaas
03/16/09 18:38
Modified:
  03/16/09 19:40

Read: 1632 times
Germany


 
#163513 - Try this, Aamir...
Responding to: Kai Klaas's previous message
I have thought about your application a bit and wrote a piece of code.

But first some basic questions:

How to fabricate the pixel matrix?

A text containing 50 characters yields a 50 x 6 = 300 bit =38 bytes wide pixel pattern per pixel row, if each character is displayed by the help of 5 x 7 matrix and a 6. pixel column is used to separate consecutive characters from another. The 8. pixel row can be used to underline certain characters.

You have additionally to think about how to separate the end of text from the begin when scrolling. So, additional bytes should be added to the above pixel pattern. To allow the display to become entirely empty after the text has been fully scrolled, at least 80 bit = 10 bytes should be added to the pattern. These bytes need not to contain "blanks", but can also show dashes, dots or something similar. By this your pixel matrix contains two consecutive blocks of pixels patterns, the "blank" pixel pattern and the "text" pixel pattern. In the following assume, that the pixel matrix starts with the blank pixel pattern.


How to store the pixel matrix in code memory?

So, you end up with a pixel matrix of 8 pixel rows each containing 48 bytes. This pixel matrix, Aamir, you want to store in the code memory. This is a good idea, as the 8 x 48 byte = 384 byte wide pixel matrix cannot reside in a standard 8052's RAM anyway. The disadvantage is that only a finite set of messages can be displayed with a programmed micro.

As you intend to use shift registers for displaying entire rows, the pixel pattern must be stored in a manner that each byte represents a sequence of consecutive pixels of a pixel row. Then the shiftings can be done very easily. Storing bytes containing pixel columns, on the other hand, would only be wise, if you intend to drive pixel columns instead of pixel rows.

It's a good idea to store the pixel pattern in the code memory in the following manner. At the first memory location you store the left-most byte of uppermost pixel row of pixel pattern. Second memory location contains the consecutive byte of uppermost pixel row. The 48. memory location contains the right-most byte of uppermost pixel row. The 49. memory location will have the left-most byte of second pixel row. And so on. Don't forget, that the left-most 10 bytes of each row represent the blank pixel pattern.


How to do the shiftings?

The idea is, not to shift the whole pixel matrix of 48 bytes = 384 bits into the pixel row shift register, but to take only those bytes that actually appear on the 10 byte = 80 bit wide display. Then, only 80...87 shiftings have to be accomplished instead of up to 384, which would take way too much time!

To find out which bytes have to be taken out of the pixel matrix for the shiftings and to find out how many shiftings have actually to be carried you must first define the shifting "Index". This index can be in the range 0...383, corresponding to the 384 bits of each pixel row.

Index = 0 means that the whole blank pixel pattern has been shifted into the display and that the text pattern is just not yet displayed. (One shifting more and the first text pixel column could be seen.) For the shifting the first 11 bytes of row have to be taken and 80 shiftings have to be done. (Actually, for Index = 0 you only need to take the first 10 bytes. But for most other Index you need to take 11 bytes, so you take 11 bytes for all Index.)

If Index = 1, then the first 11 bytes have to be taken and 81 shiftings have to be done. If Index = 2, again the first 11 bytes have to be taken but 82 shiftings have to be done. If Index = 3, again the first 11 bytes have to be taken but 83 shiftings have to be done.

The same procedure until Index = 7. But if Index = 8, then the 2. to the 12. bytes of pixel row have to be taken and 80 shiftings have to be done.

So, you see, if Index equals multiples of 8, then the 11 bytes wide pixel block for the shiftings wanders to the right by a step of one byte. You also see, that the shiftings count up from 80 to 87 all the time: If Index equals multiples of 8, then always 80 shiftings have to be done.

If the pixel block for the shiftings has reached the right end of pixel matrix, which happens for the first time when Index = 384 - 80 = 304, pixels from the begin of pixel row have to be taken again.

The code's task is now to get the right 11 pixel bytes into the RAM of micro and to feed the pixel row shift register (BU4094s). Everything with repect to this index.


How to do the scrolling?

By a simple timer controlled incrementing of Index.

Well, in the following code not everything is derived from Index actually, but some counters are running in parallel to the Index counter. You will find them very quickly when having a look at the code (I hope).

The code corresponds to your scheme with the BDX54C anode drivers, which I assume are driven by the Port0 lines. The 4094 shift register is fed by the micro via P1.0 (Data), P1.1 (Clock) and P1.2 (Strobe) lines.

The code feeds the AT89S52's internal watchdog and allows a display refresh rate of 130Hz.

Take care, the code isn't tested at all. Experiment with it and have fun!

;Scrolling software idea for a 8 x 80bit LED matrix. Through this LED
;matrix a much bigger pixel matrix is scrolled. 

;The pixel matrix contains 8 rows, each 48 bytes wide. The first 10 bytes
;represent the blank information, the remaining 38 bytes represent the
;text to be scrolled.

;From the pixel matrix, stored at address 7168, an 11 byte wide block is
;selected. The first 10 bytes of this block are fully shifted into the
;4096. From the 11th byte only a certain number (represented by "SHIFT"
;(=0..7)) is shifted into the 4094.

;The start address of this block depends on STRT_BYTE (=0..47),ROW_OFS_L,
;ROW_OFS_H (=0,48,96,144...336, by other words =ROW * 48) and the start
;address of pixel matrix (MATRX_STRT_L, MATRX_STRT_H).
;ROW (=0..7) defines the row to be shifted and displayed.

;The actual scroll position is represented by INDEX_L,INDEX_H (=0..383).
;This INDEX is "0", when the blank block is fully shifted into the 4094
;and the text is just not yet visible.

;REFRESH is incremented when a full set of 8 rows has been displayed.
;When REFRESH equals SCRL-RATE, then the display is scrolled by one
;pixel column. This is every 16 * 8 * 950Ásec = 0.12sec here, assuming
;11.0592MHz clock speed. Adjust SCRL_RATE to change the scroll speed.




                $NOMOD51
                $INCLUDE (89s52.mcu)


                DATA_OUT        BIT     P1.0
                CLOCK           BIT     P1.1
                STROBE          BIT     P1.2

                ANODE_DRIV      DATA    30H
                INDEX_L         DATA    31H
                INDEX_H         DATA    32H
                REFRESH         DATA    33H
                ROW             DATA    34H
                ROW_OFS_L       DATA    35H
                ROW_OFS_H       DATA    36H
                SHIFT           DATA    37H
                STRT_BYTE       DATA    38H

                SCRL_RATE       EQU      16
                MATRX_STRT_L    EQU     00H 
                MATRX_STRT_H    EQU     1CH


                ORG 0
            
                SJMP Start

                ORG 002BH

Start:          MOV AUXR,#00011001B   ;AT89S52 specific status byte           
                MOV TMOD,#00000001B   ;Configure Timer 0 (Mode 1)
                MOV TH0,#252          ;Set 950Ásec
                MOV TL0,#148   
                SETB TR0              ;Start Timer 0
                CLR CLOCK             ;Prepare the first shifting

Initialize:     CLR A                 ;Set registers to "0"    
                MOV STRT_BYTE,A       
                MOV ROW,A
                MOV ROW_OFS_L,A
                MOV ROW_OFS_H,A
                MOV INDEX_L,A
                MOV INDEX_H,A
                MOV REFRESH,A
                MOV SHIFT,A
                MOV ANODE_DRIV,#11111110B   ;Prepare ANODE_DRIV for first
                                            ;row.

Main_loop:      MOV WDTRST,#01EH      ;Feed the watchdog
                MOV WDTRST,#0E1H
                MOV R6,#10            ;10 pixel bytes to be selected and
                                      ;shifted.
                MOV R7,STRT_BYTE      ;Copy STRT_BYTE into R7
                MOV A,MATRX_STRT_L    ;Fabricate the start address of 11
                ADD A,ROW_OFS_L       ;bytes wide block.
                MOV DP0L,A            ;Feed the DPTR with the base address
                MOV A,MATRX_STRT_H    ;and use R7 as a "looping" address
                ADDC A,ROW_OFS_H      ;offset.
                MOV DP0H,A

Get_bytes:      MOV A,R7              ;R7 contains the address offset
                MOV AUXR1,#0          ;89S52 needs DPTR to be defined
                MOVC A,@A+DPTR        ;Fetch the pixel byte

                MOV R5,#8             ;All 8 bits of pixel byte
Shift_loop1:    RLC A                 ;Shift the pixel byte fully into
                MOV DATA_OUT,C        ;the 4094.    
                SETB CLOCK
                CLR CLOCK
                DJNZ R5,Shift_loop1   ;All 8 bits shifted?

                INC R7                ;Address the next pixel byte
                CJNE R7,#48,Repeat    ;If end of pixel matrix is reached,
                MOV R7,#0             ;fetch it from the begin again.

Repeat:         DJNZ R6,Get_bytes     ;First 10 pixel bytes shifted?

                MOV R5,SHIFT          ;Copy SHIFT into R5
                CJNE R5,#0,Last_byte  ;11th pixel byte to be shifted?
                SJMP Wait             ;11th pixel byte need not to be
                                      ;shifted into the 4094.                 
Last_byte:      MOV A,R7              ;R7 addresses the 11th pixel byte
                MOV AUXR1,#0          ;89S52 needs DPTR to be defined
                MOVC A,@A+DPTR        ;Fetch the 11th pixel byte

Shift_loop2:    RLC A                 ;11.pixel byte is partially shifted
                MOV DATA_OUT,C        ;into the 4094. SHIFT represents
                SETB CLOCK            ;the number of bits to be shifted.
                CLR CLOCK              
                DJNZ R5,Shift_loop2    

Wait:           JNB TF0,Wait          ;Timer 0 overrun?
                MOV P0,#255           ;Turn-off the anode drivers
                CLR TR0               ;Stop Timer 0
                CLR TF0               ;Reset timer flag bit (TF0)
                MOV TMOD,#00000001B   ;Configure Timer 0 (Mode 1)
                MOV TH0,#252          ;Set 950Ásec
                MOV TL0,#148   
                SETB TR0              ;Start Timer 0
                SETB STROBE           ;Latch the new column data in 
                CLR STROBE            ;the 4094s.
                MOV A,ANODE_DRIV      ;Copy ANODE_DRIV into A
                MOV P0,A              ;Turn-on selected anode driver
                RL A                  ;Prepare ANODE_DRIV for next row
                MOV ANODE_DRIV,A
                INC ROW               ;Prepare next row
                MOV A,ROW_OFS_L       ;Fabricate next ROW_OFS_L/H address
                ADD A,#48
                MOV ROW_OFS_L,A
                MOV A,ROW_OFS_H
                ADDC A,#0
                MOV ROW_OFS_H,A
                MOV A,ROW
                CJNE A,#8,Go_back     ;All 8 rows shifted?
                CLR A                 ;8 rows shifted, so reset ROW
                MOV ROW,A             ;and ROW_OFS_L/H
                MOV ROW_OFS_L,A
                MOV ROW_OFS_H,A
                INC REFRESH           ;and increment REFRESH.
                MOV A,REFRESH
                CJNE A,SCRL_RATE,Go_back    ;Time to scroll?
                SJMP Prepare_scroll

Go_back:        LJMP Main_loop        ;Jump back and shift the next row

Prepare_scroll: MOV REFRESH,#0        ;Reset REFRESH
                MOV A,INDEX_L         ;Increment INDEX_L/H
                ADD A,#1
                MOV INDEX_L,A
                MOV A,INDEX_H
                ADDC A,#0
                MOV INDEX_H,A
                INC SHIFT             ;Increment SHIFT
                MOV A,SHIFT
                CJNE A,#8,Go_back     ;SHIFT to be reseted?
                MOV SHIFT,#0          ;Reset SHIFT and
                INC STRT_BYTE         ;increment STRT_BYTE.
                MOV A,INDEX_L         ;INDEX_L/H = 384?
                CJNE A,#128,Go_back   ;No,so go back and shift next row
                MOV A,INDEX_H
                CJNE A,#1,Go_back
                LJMP Initialize       ;INDEX_L/H = 384,so initialize and
                                      ;start all over again.


                org 7168

                DB 0,0,0,0,0,0,0,0,0,0   ;Uppermost row of pixel matrix
                DB 255,255,255,255,255   ;"0" represents the blank pixels,
                DB 255,255,255,255,255   ;"255" the character pixels.
                DB 255,255,255,255,255
                DB 255,255,255,255,255   ;Each row contains 48 bytes
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255
                DB 0,0,0,0,0,0,0,0,0,0   ;2.row of pixel matrix
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255
                DB 0,0,0,0,0,0,0,0,0,0   ;3.row of pixel matrix
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255
                DB 0,0,0,0,0,0,0,0,0,0   ;4.row of pixel matrix
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255
                DB 0,0,0,0,0,0,0,0,0,0   ;5.row of pixel matrix
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255
                DB 0,0,0,0,0,0,0,0,0,0   ;6.row of pixel matrix
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255
                DB 0,0,0,0,0,0,0,0,0,0   ;7.row of pixel matrix
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255
                DB 0,0,0,0,0,0,0,0,0,0   ;8.row of pixel matrix
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255,255,255
                DB 255,255,255


                end



Kai


List of 307 messages in thread
TopicAuthorDate
Scrolling Message in LED Display with 8051??      Aamir Javaid      12/10/08 01:11      
   2 separate problems      Andy Neil      12/10/08 01:22      
   the simple way      Erik Malund      12/10/08 05:36      
      didnot get you      Aamir Javaid      12/11/08 03:13      
         Standard circular buffer      Per Westermark      12/11/08 03:28      
            Thanks      Aamir Javaid      12/11/08 04:03      
               Flickering in scrolling      Aamir Javaid      02/22/09 22:52      
                  Clip to viewport      Per Westermark      02/22/09 23:02      
                     Testing on 8x8 display.      Aamir Javaid      02/22/09 23:13      
                        Write fastest loop and count instructions      Per Westermark      02/22/09 23:35      
                           Any other suggestions      Aamir Javaid      02/23/09 00:21      
                              yes and no      Erik Malund      02/23/09 07:21      
                                 Frankly speaking      Aamir Javaid      02/24/09 00:47      
                                    time, time, time      Erik Malund      02/24/09 06:54      
                              You should investigate old-style monochrome video adapters      Richard Erlacher      02/23/09 09:26      
                                 but pretty close      Erik Malund      02/23/09 09:40      
                                    not wishing to start a debate ...      Richard Erlacher      02/23/09 13:17      
                                       pixel rate      Andy Neil      02/23/09 13:41      
                                          Yes, that's true, but it's irrelevant      Richard Erlacher      02/23/09 15:34      
                                             Persistence matters, and algorithm      Per Westermark      02/24/09 03:23      
                                                I believe there's a difference in approach here      Richard Erlacher      02/24/09 14:17      
                                                   Shift registers to drive rows, not columns.      Per Westermark      02/24/09 14:48      
                                                      ...which is why they don'tfit this sort of application      Richard Erlacher      02/24/09 17:03      
                                                         Think about pulse quota when multiplexing      Per Westermark      02/25/09 02:43      
                                                            Yes, the multiplexing affects ultimate brightness ...      Richard Erlacher      02/25/09 10:03      
                                                               never heard of 2 lines???      Erik Malund      02/25/09 12:26      
                                                                  Yes, but most people can only read one at a time      Richard Erlacher      02/25/09 16:05      
                                                                     16 pix      Per Westermark      02/25/09 16:33      
                                                                        It's news to me ...      Richard Erlacher      02/25/09 18:49      
                                                                           Good with forums      Per Westermark      02/26/09 01:02      
                                                      Do you mean a REGISTERED shift register?      Richard Erlacher      02/28/09 06:57      
                                                         Yes        Per Westermark      02/28/09 07:08      
                                                            Absolutely!      Kai Klaas      02/28/09 09:20      
                                                         never seen one      Erik Malund      02/28/09 07:32      
                                                      That's the answer i was looking for...      Aamir Javaid      03/02/09 23:03      
                                       one can change the colour on an LED      Andy Neil      02/23/09 13:46      
                                       a monochrome display has one LED per pixel      Erik Malund      02/23/09 14:59      
                                          It is seldom so simple as one would like      Richard Erlacher      02/23/09 15:52      
                                             I too read 8x8 as pixels/LEDs. However, probelm with scroll      Per Westermark      02/24/09 03:45      
                                                Please leave that CRT      Aamir Javaid      02/24/09 23:04      
                                                   But we area focused      Per Westermark      02/25/09 02:04      
                                                   Chequebook time!      Andy Neil      02/25/09 03:07      
                                                   You haven't told us anything useable!      Richard Erlacher      02/25/09 09:39      
                                                      The Information      Aamir Javaid      02/25/09 22:21      
                                                      The Information      Aamir Javaid      02/25/09 22:21      
                                                         Mr. amir      Jiya Siddiqui      02/26/09 13:19      
                                                      The Information      Aamir Javaid      02/25/09 22:21      
                                                      The Information      Aamir Javaid      02/25/09 22:28      
                                                      The Information      Aamir Javaid      02/25/09 22:33      
                                                         Quoting Andy on this      Per Westermark      02/26/09 01:21      
                                                            re the rating of "Quoting Andy on this"      Erik Malund      02/26/09 09:19      
                                                               LOL      Per Westermark      02/26/09 09:33      
                                                                  It was me, Per...      Kai Klaas      02/26/09 09:56      
                                                                     Feedback      Per Westermark      02/26/09 11:23      
                                                                        I agree with you in all points, but...      Kai Klaas      02/26/09 14:55      
                                                                           I agree, Kai --- in most cases ...        Erik Malund      02/26/09 15:13      
                                                                              Kick-starting threads do require some form of pushing      Per Westermark      02/26/09 16:25      
                                                         That will be UGLY      Erik Malund      02/26/09 07:09      
                                                            Not necessarily...      Kai Klaas      02/26/09 09:44      
                                                         That is not ALL the information.      Richard Erlacher      02/26/09 09:56      
            Looked at circular buffer yet?      Per Westermark      02/23/09 00:48      
   Has anyone looked at Allegro?      Hal Albach      02/26/09 20:14      
      A specific chip for the shift-register solution      Per Westermark      02/27/09 01:22      
         Think about total power loss      Per Westermark      02/27/09 01:57      
            you tell me      Erik Malund      02/27/09 06:16      
      the A6833 and similar offerings      Erik Malund      02/27/09 06:24      
   Code, problem, information and schematic.      Aamir Javaid      03/05/09 21:59      
      BU4094 is fast enough, but...      Kai Klaas      03/06/09 07:09      
         look at 74HC595      Richard Erlacher      03/06/09 17:52      
            Yes, and not to forget the 74HC4094...      Kai Klaas      03/07/09 06:42      
               and 80 resistors      Erik Malund      03/07/09 09:20      
                  Mickey Mousing?? Availibility!      Kai Klaas      03/07/09 19:19      
                     my absolute impression ...      Erik Malund      03/08/09 09:57      
                        Almost total silence      Per Westermark      03/08/09 10:31      
                           ??      Kai Klaas      03/08/09 11:47      
                              How to activate Aamir?      Per Westermark      03/08/09 14:19      
                                 I don't want to activate Aamir!      Kai Klaas      03/08/09 14:34      
                                    Yes, most comments here are free-running without the OP      Per Westermark      03/08/09 15:05      
                                       Maybe the wrong sorts of questions were asked      Richard Erlacher      03/08/09 19:09      
                        Let's see what the O/P wants to do      Richard Erlacher      03/08/09 10:35      
                           with the amount of effort the OP shows ....      Erik Malund      03/09/09 08:12      
                              What you have failed to consider ...      Richard Erlacher      03/09/09 08:40      
                                 did you read      Erik Malund      03/09/09 08:45      
                                    Yes, I did!      Richard Erlacher      03/09/09 08:58      
                        And my absolute impression is...      Kai Klaas      03/08/09 11:36      
                           why should I do that?      Erik Malund      03/09/09 08:29      
                              I have to agree      Richard Erlacher      03/09/09 08:56      
                  What does it cost? How many would be needed?      Richard Erlacher      03/08/09 10:53      
                     Exactly!      Kai Klaas      03/08/09 11:59      
                     ST2221 EQUIVALENT      Erik Malund      03/09/09 08:42      
                        It's not widely available in the developing world      Richard Erlacher      03/09/09 09:11      
                           Max power loss at high ambient temperatures      Per Westermark      03/09/09 09:22      
                              Interesting point ... but ...      Richard Erlacher      03/09/09 10:46      
                                 8- or 16-bit drivers for different applications      Per Westermark      03/09/09 11:24      
                           because      Erik Malund      03/09/09 10:35      
                              Is this a chicken and egg sort of question?      Richard Erlacher      03/09/09 10:54      
                                 Different chips for different problems      Per Westermark      03/09/09 11:06      
                                 no, applea and oranges      Erik Malund      03/09/09 12:47      
                                    Isn't that a design parameter?      Richard Erlacher      03/09/09 13:35      
                                       Physics and practical realities      Per Westermark      03/09/09 14:09      
                                          In some cases, perhaps LED's are not the right technology      Richard Erlacher      03/09/09 17:52      
                                       and what does all that to do with ....      Erik Malund      03/09/09 14:59      
                                          They have to remain within specified limits.      Richard Erlacher      03/09/09 18:03      
                                             Still missing muxed concept      Per Westermark      03/10/09 03:50      
                                                No ... I'm not missing the concept ...      Richard Erlacher      03/10/09 10:16      
                                                   yes you are      Erik Malund      03/10/09 10:35      
                                                      You're thinking too narrowly, methinks.      Richard Erlacher      03/10/09 12:29      
                                                         no, you are muddling      Erik Malund      03/10/09 12:46      
                                                            It's just another way to manage a big sign      Richard Erlacher      03/10/09 15:16      
                                                               not so, back at ya      Erik Malund      03/11/09 06:35      
                                                                  PWM or shorter on times.      Per Westermark      03/11/09 06:46      
                                                                  There's more than one way to skin a cat      Richard Erlacher      03/11/09 10:50      
                                                                     Start producing signs.      Per Westermark      03/11/09 11:00      
                                                                        Those arguments are weak!      Richard Erlacher      03/11/09 11:25      
                                                                           not for those that have an inkling of understanding      Erik Malund      03/11/09 13:48      
                                                                              So ... how fast can you clock 'em?      Richard Erlacher      03/11/09 22:40      
                                                                                 if you had read and not muddled....      Erik Malund      03/12/09 06:08      
                                                                                    Not Bad ! That IS a lot more reasonable!      Richard Erlacher      03/12/09 09:36      
                                                                                       why on earth would you want to do that      Erik Malund      03/12/09 10:37      
                                                                                          If a little bit is good, sometimes more is better ...      Richard Erlacher      03/12/09 12:45      
                                                                                             you might, I wouldn't      Erik Malund      03/12/09 13:40      
                                                                                                I can envision such a thing ... but I don't build signs      Richard Erlacher      03/12/09 23:16      
                                                                                                   I feel the need to SHOUT      Erik Malund      03/13/09 07:21      
                                                                                                      Time to get back to scrolling      Richard Erlacher      03/13/09 11:05      
                                                                                                         as long as the CC drives one pixel      Erik Malund      03/13/09 11:31      
                                                                                                            Don't everyone love a DC-driven sign?      Per Westermark      03/13/09 12:13      
                                                                                                               In the interest of discussion ...      Richard Erlacher      03/13/09 16:39      
                                                                                                                  get your head out of your ....      Erik Malund      03/14/09 07:14      
                                                                                                                     consider ALL the alternatives ...      Richard Erlacher      03/14/09 09:24      
                                                                                                                        Inkling?      Per Westermark      03/14/09 09:59      
                                                                                                                           It comes down to why this is being discussed      Richard Erlacher      03/14/09 15:55      
                                                                                                                              Where is the progress?      Per Westermark      03/15/09 04:47      
                                                                                                                                 Robert Erlacher ??      AP Charles      03/15/09 07:13      
                                                                                                                                    Oops      Per Westermark      03/15/09 07:41      
                                                                                                                                 Let's leave irrelevant issues out ... for now      Richard Erlacher      03/15/09 13:04      
                                                                                                                                    Quote examples      Per Westermark      03/15/09 14:59      
                                                                                                                                       No citation needed!      Richard Erlacher      03/16/09 00:06      
                                                                                                            ... about that schematic ...      Richard Erlacher      03/13/09 16:50      
                                                                                                               Still thinking single diode      Per Westermark      03/14/09 04:26      
                                                                                                                  It doesn't HAVE to be done in a conventional granularity      Richard Erlacher      03/14/09 07:10      
                                                                                                               I do not think so      Erik Malund      03/14/09 07:10      
                                                                        One other thing ...      Richard Erlacher      03/11/09 11:31      
                                                                     THAT IS what PWM does      Erik Malund      03/11/09 13:43      
                                                                        For that, you don't need dedicated hardware      Richard Erlacher      03/11/09 22:42      
                                                                           never said so      Erik Malund      03/12/09 06:09      
                                                                              Give the customer value while making money      Per Westermark      03/12/09 17:45      
                                                                                 A lot of intersting issues have been forced to the surface      Richard Erlacher      03/12/09 23:47      
                                                                                    Go for KISS      Per Westermark      03/13/09 02:23      
                                             fruit salad      Erik Malund      03/10/09 06:22      
                                                Not exactly ... I think you're ignoring the point      Richard Erlacher      03/10/09 09:47      
                                                   this is where you are confoosed      Erik Malund      03/10/09 10:28      
                                                      There's nothing confusing about the procedure      Richard Erlacher      03/10/09 16:48      
                                                         NO, NO, NO      Erik Malund      03/11/09 06:51      
                                                            Yes, non-mpx is probably easier ...      Richard Erlacher      03/11/09 10:44      
                                                         Resistor on varying-current side? Hot, hot, hot      Per Westermark      03/11/09 07:04      
                                                   Please forget CRT      Per Westermark      03/10/09 11:17      
      why this complex, why so enamored by darlingtons?      Erik Malund      03/06/09 08:38      
         Of course, your Allegro thingis would perfectly fit...      Kai Klaas      03/06/09 09:28      
            not the transistors, the ULN in the columns      Erik Malund      03/06/09 09:59      
      Back to square one. First experiment with fast output      Per Westermark      03/06/09 09:59      
      Power is not Sufficient      Qamrul Islam      03/08/09 15:08      
         Semi-correct      Per Westermark      03/08/09 15:56      
      Sorry guys      Aamir Javaid      03/09/09 00:26      
   Switch statement      Per Westermark      03/06/09 10:07      
      ULN2803 ????      Jiya Siddiqui      03/06/09 11:47      
         WHY?????      Erik Malund      03/06/09 13:50      
         The 2803's OK ... with a current source Anode driver      Richard Erlacher      03/06/09 18:02      
            Yes, unless high cathode currents...      Kai Klaas      03/07/09 06:57      
               If he's sinking current from, at most, 16 cathodes ...      Richard Erlacher      03/07/09 12:26      
                  Not 16 at a time. 0 or 1 for column. 0..80 for row        Per Westermark      03/07/09 12:38      
                     I got it from the O/P's first post      Richard Erlacher      03/07/09 15:02      
                        But you don't do 80:1      Per Westermark      03/07/09 15:39      
                           I couldn't have said it better myself!      Richard Erlacher      03/07/09 16:07      
                     Code hang-ups...      Kai Klaas      03/07/09 15:51      
                        Watchdog is nice      Per Westermark      03/07/09 16:09      
                        not a 'bright' idea      Erik Malund      03/08/09 09:50      
                           Yes, muxed displays requires high currents to not be dim      Per Westermark      03/08/09 10:28      
            which varies by a factor of 1:80      Erik Malund      03/07/09 09:27      
               It's not dirt-simple, but it's not rocket-science, either      Richard Erlacher      03/07/09 12:31      
                  first/second????      Erik Malund      03/07/09 13:44      
                  evidently it is      Erik Malund      03/30/09 13:22      
                     I just came to think of this quiz      Erik Malund      03/31/09 06:04      
   Happy three months      Per Westermark      03/10/09 04:44      
      It didnot work for me again.....      Aamir Javaid      03/11/09 00:52      
         are you familiar with Ohms law      Erik Malund      03/11/09 06:57      
         Write test-code for driving the diodes      Per Westermark      03/11/09 09:38      
         I'm afraid to tell you,...      Kai Klaas      03/14/09 14:22      
            Don't shift so much      Per Westermark      03/14/09 14:30      
               Yes, he must shift byte-wise...      Kai Klaas      03/14/09 14:39      
                  The alternative...      Kai Klaas      03/14/09 15:51      
                     Try this, Aamir...      Kai Klaas      03/16/09 18:38      
                        Thanks Sir.......      Aamir Javaid      03/17/09 03:01      
                        I knew someone would do his work for him!      Richard Erlacher      03/17/09 09:39      
                           Yes, and it was fun!      Kai Klaas      03/17/09 09:56      
                              Yes, of course ... but they were far too complex      Richard Erlacher      03/17/09 17:29      
                                 I'm really sorry that they were "far too complex"...      Kai Klaas      03/17/09 18:13      
                                    one step at a time      Per Westermark      03/17/09 20:03      
                                       All many of these guys want is someone to do their work      Richard Erlacher      03/17/09 23:13      
                                       Big-bang        AP Charles      03/18/09 00:56      
                                          Lessons learned      Per Westermark      03/18/09 04:34      
                                             Lessons...      Kai Klaas      03/18/09 07:07      
                                                the difference      Erik Malund      03/18/09 07:13      
                                                   He learns and learns and learns...      Kai Klaas      03/18/09 07:21      
                                                      that would be true      Erik Malund      03/18/09 07:55      
                                                         That's the point...      Kai Klaas      03/18/09 08:04      
                                                            show me one      Erik Malund      03/18/09 11:17      
                                                      Only feedback tells where the correct level is      Per Westermark      03/18/09 07:59      
                                                Knowledge is still the morst valuable gift        Per Westermark      03/18/09 07:49      
                                                   You really never had a look at something bigger??      Kai Klaas      03/18/09 08:11      
                                                      Read what I write, not what you want me to write      Per Westermark      03/18/09 08:30      
                                                         Sorry, Per, but...      Kai Klaas      03/18/09 09:46      
                                                            Atleast give OP some time      AP Charles      03/18/09 10:26      
                                                               male cow manure      Erik Malund      03/18/09 11:24      
                                                               This guy is a STUDENT! And probably a lazy one.      Richard Erlacher      03/18/09 13:37      
                                                                  Poor...      Kai Klaas      03/18/09 14:52      
                                                                     It should be a career-ender      Richard Erlacher      03/18/09 22:30      
                                                               Ignorance is bliss?      Per Westermark      03/18/09 14:26      
                                                                  Is this a Social Work forum?      AP Charles      03/19/09 02:52      
                                                                     Is this a Social Work forum? - no      Erik Malund      03/19/09 06:47      
                                                                        ethical behaviour        AP Charles      03/19/09 08:11      
                                                                           Good elbows...      Kai Klaas      03/19/09 09:23      
                                                                              Some people are just lazy, and think they're entitled.      Richard Erlacher      03/19/09 10:10      
                                                                              Robots has no feelings      AP Charles      03/19/09 10:11      
                                                                     Where do you put the limit?      Per Westermark      03/19/09 09:58      
                                                                        Its not the point      AP Charles      03/19/09 10:37      
                                                                           Prove your point!      Per Westermark      03/19/09 14:35      
                                                                              point of disagreement ?      AP Charles      03/20/09 03:04      
                                                                                 Teflon-avoidance of arguments      Per Westermark      03/20/09 04:47      
                                                                                    back to the old one      Erik Malund      03/20/09 05:59      
                                                                                 There must be a willingness to do the work!      Richard Erlacher      03/20/09 17:16      
                                                                                    a nasty thought      Erik Malund      03/21/09 07:40      
                                          by silence the OP has admitted      Erik Malund      03/18/09 06:31      
                                             He has admitted??      Kai Klaas      03/18/09 07:14      
                                                it is a known fact that      Erik Malund      03/18/09 07:19      
                                                   Do you think, that I aggree if I don't reply...      Kai Klaas      03/18/09 07:24      
                                                      yes, IF      Erik Malund      03/18/09 07:41      
                                                It may not have been in this thread      Richard Erlacher      03/18/09 09:02      
                                                   Plain bogus...      Kai Klaas      03/18/09 09:51      
                                                   School projects always problematic      Per Westermark      03/18/09 09:52      
                                                      This is a recurring theme      Richard Erlacher      03/18/09 13:54      
                                                         Regular on Keil too      Per Westermark      03/18/09 14:36      
                                    Well, too many components      Richard Erlacher      03/17/09 23:12      
                                    I was looking for a product I could buy, not a work-product.      Richard Erlacher      03/18/09 13:40      
      And still stuck on the basics      Andy Neil      03/16/09 09:32      
   This one's not too costly!      Richard Erlacher      03/15/09 13:29      
      Nice one      Per Westermark      03/15/09 14:34      
   facts      Erik Malund      03/16/09 06:42      
   Silence talks...      Per Westermark      03/28/09 08:36      
      It's because the due-date of his assignment has passed      Richard Erlacher      03/28/09 09:11      
         No the OP, but the two drive-by-shooters      Per Westermark      03/28/09 09:32      
            For Per Westermark      AP Charles      03/28/09 10:07      
            "Drive-by-shooters"? Are you cuckoo??      Kai Klaas      03/28/09 11:56      
               I think that was the basic problem      Andy Neil      03/28/09 12:58      
                  Yes, and as we do not know the state of knowledge...      Kai Klaas      03/28/09 16:00      
                     Once more you focus on bowing and other nonsense      Per Westermark      03/28/09 16:40      
                        Do you feel better now??      Kai Klaas      03/28/09 16:50      
                           Why?      Per Westermark      03/28/09 16:55      
                              Answers...      Kai Klaas      03/28/09 17:40      
                                 Try looking from the other direction      Per Westermark      03/28/09 18:36      
                                    Forum rules...      Kai Klaas      03/28/09 19:21      
                                       Constant misunderstandings, or kicking in open doors      Per Westermark      03/28/09 20:47      
                                          bow? no, but questions should be answered.      Erik Malund      03/29/09 06:53      
                     but we do      Erik Malund      03/28/09 16:44      
                        Making mistakes and confusing things...      Kai Klaas      03/28/09 16:57      
                           Missing help?      Per Westermark      03/28/09 17:05      
                              Why do you all the time interfere in...      Kai Klaas      03/28/09 17:43      
                                 When we ask an O/P a question ...      Richard Erlacher      03/28/09 19:01      
                                    But that's it, Richard!      Kai Klaas      03/28/09 19:26      
                                       You're right, Kai, but not in the way that you might think      Richard Erlacher      03/28/09 22:32      
                                 Can't see "not helped"      Per Westermark      03/28/09 19:46      
                                    I'm tired, Per...      Kai Klaas      03/28/09 19:55      
                                       Weapons down Kai :)      AP Charles      03/29/09 02:27      
                                       we all are      Erik Malund      03/29/09 07:04      
                                          we all are -      AP Charles      03/29/09 09:30      
                                             So enumerate the factual errors then      Per Westermark      03/29/09 10:03      
                                                You were wrong      AP Charles      03/29/09 10:41      
                                                   I wish that someday ...      Erik Malund      03/29/09 10:54      
                                                      I wish that someday ... Is that so      AP Charles      03/30/09 02:25      
                                                         And your argument was?      Per Westermark      03/30/09 02:42      
                                                            Example      AP Charles      03/30/09 02:57      
                                                               Just curious      Per Westermark      03/30/09 03:47      
                                                                  No reverse way just wanted to show      AP Charles      03/30/09 05:39      
                                                                     assisted != having others to do the job      Per Westermark      03/30/09 05:57      
                                                                        From this at least it dosent make      AP Charles      03/30/09 06:42      
                                                                           Come on, now, Ap Charles ...      Richard Erlacher      03/30/09 07:34      
                                                                              Have you read what Aamir wrote?      Kai Klaas      03/30/09 07:52      
                                                                                 Yes, it looks like part of the assignment spec      Richard Erlacher      03/30/09 11:21      
                                                                                    Assignment specs? Hardly...      Kai Klaas      03/30/09 14:40      
                                                                                       I guess we see different things in the quoted post      Richard Erlacher      03/30/09 17:58      
                                                                                          These are good arguments...      Kai Klaas      03/30/09 19:07      
                                                                                             We'll never know for certain      Richard Erlacher      03/30/09 22:51      
                                                                                       switch not the big problem      Per Westermark      03/31/09 00:41      
                                                                                          Direct and Indirect calls      AP Charles      03/31/09 03:15      
                                                                                             Size of feet?      Per Westermark      03/31/09 03:25      
                                                                                                I can see your point      AP Charles      03/31/09 04:10      
                                                                                                   Probably yet another language problem      Per Westermark      03/31/09 05:26      
                                                                                                      The O/P has a part to play, as do we of 8052.COM      Richard Erlacher      03/31/09 07:04      
                                                                                                      Yes      AP Charles      03/31/09 07:21      
                                                                                          Oh dear, Per, please...      Kai Klaas      03/31/09 09:06      
                                                                                             In the eye of the beholder      Per Westermark      03/31/09 15:13      
                                                                                                Sorry, I didn't want to hurt you!      Kai Klaas      03/31/09 17:56      
                                                                                 again, it is obvious      Erik Malund      03/30/09 12:19      
                                                            Not big-bang solution, but snippet of code!      Kai Klaas      03/30/09 08:12      
                                                I'm not the only one who confuses things...      Kai Klaas      03/29/09 11:45      
                                                   Yes, language barrier      Per Westermark      03/29/09 12:19      
                                                   Yes, it's true ...      Richard Erlacher      03/29/09 12:50      
                           wrong question      Erik Malund      03/28/09 17:32      

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