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Richard Erlacher
09/17/12 01:54
Read: 512 times
Denver, Co

#188363 - Not all 805x variants are the same
Responding to: ???'s previous message
... which is why you have to read the datasheet for each variant you're considering.

Many of the classic 805x types provide that multiplexed external address and data bus controlled by nRD, nWR, nPSEN, and ALE. Some of the newer ones do not, however.

The SiLabs 'F12's have more ways of interfacing external memory than that, including a non-multiplexed bus. As I've pointed out, they also support I2C and SPI with hardware. Further, they allow you to modify the external bus timing if you find it necessary.

I urge you to read the datasheet for the SiLabs 'f12x-series just to give you a detailed look at all the features. They're very capable, though they require firm understanding. That, in fact, is true of nearly any MCU.

I don't recommend using wire-wrap unless you require quick turn-around. I can wrap a circuit on the order of the one you've suggested you're using, in about an hour, including very excellent power supply bypass, which is very important in any prototype. When I'm finished, I can salvage all the sockets and even some of the bypass cap's, though the small SMT passives are generally sacrificed. Wire-wrapped circuits are generally very robust and tolerate much "fiddling" as part of the process of startup. I mention this only because some people believe it a good idea to use a "ProtoBoard", with those inserted wires to make connections. They are very fragile and often are intermittent in their behavior.


List of 28 messages in thread
Nokia 3310 display [PCD8544] dot problem      Samarth Godara      09/14/12 08:02      
   NOTE-      Samarth Godara      09/14/12 08:32      
      Graphics Displays      Michael Karas      09/14/12 09:10      
         memory management      Samarth Godara      09/14/12 09:31      
            it would not      Erik Malund      09/14/12 09:50      
               more help      Samarth Godara      09/14/12 10:30      
                  Search engines?      Per Westermark      09/14/12 12:20      
                     confused      Samarth Godara      09/14/12 13:13      
                        No exact answer      Per Westermark      09/14/12 13:36      
                        Type of Thinking      Michael Karas      09/14/12 14:34      
                           I second that      Erik Malund      09/15/12 08:05      
                              doubt - interfacing memory with 8051      Samarth Godara      09/15/12 11:52      
                                 Why would you want to      Hal Albach      09/15/12 16:58      
                                    Don't overlook the "extras"      Richard Erlacher      09/15/12 20:29      
                                    why to use my own design      Samarth Godara      09/15/12 20:47      
                                       which is corect, but      Erik Malund      09/16/12 06:44      
                                       Wrong approach for India        Kalpak Dabir      09/16/12 06:50      
                                          my approach + new doubt [start execution]      Samarth Godara      09/16/12 09:06      
                                             Perhaps you've overlooked some options      Richard Erlacher      09/16/12 12:44      
                                                my circuiting & a Really surprising, Good Board      Samarth Godara      09/16/12 23:00      
                                                   Not all 805x variants are the same       Richard Erlacher      09/17/12 01:54      
                                                   Besides 8051 there are other....      Kalpak Dabir      09/17/12 02:00      
                                                   BEWARE      Erik Malund      09/17/12 07:38      
                                                      Shortest path      Per Westermark      09/17/12 09:05      
                                                   use direct wiring when using point-to-point      Richard Erlacher      09/17/12 09:30      
                                 Are you determined to fail?      Erik Malund      09/15/12 19:41      
                           SiLabs isn't the only possible solution      Richard Erlacher      09/15/12 20:22      
                        Have you considered the datasheet(s) and's search?      Richard Erlacher      09/15/12 20:17      

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