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Andy Neil
11/05/12 00:34
Read: 578 times
Basingstoke
Uk


 
Msg Score: +1
 +1 Informative
#188772 - RE: is there some special "idle mode" wrt the 805x hardware?
Responding to: Joseph Hebert's previous message
Joseph Hebert said:
is there some special "idle mode" with respect to the 805x hardware?


Yes!


80C51 Family Hardware Description, p19, said:
CMOS Power Reduction Mode

CMOS versions have two power reducing modes, Idle and Power
Down. The input through which backup power is supplied during
these operations is VCC. Figure 23 shows the internal circuitry which
implements these features. In the Idle modes (IDL = 1), the oscillator
continues to run and the Interrupt, Serial Port, and Timer blocks
continue to be clocked, but the clock signal is gated off to the CPU.

In Power Down (PD = 1), the oscillator is frozen. The Idle and Power
Down Modes are activated by setting bits in Special Function
Register PCON. The address of this register is 87H. Figure 24
details its contents.

http://www.classic.nxp.com/acrobat_d...WARE_1.pdf


Some (many? most?) newer derivatives add further "power reducing modes" - see specific documentation for details...

List of 8 messages in thread
TopicAuthorDate
idle mode problem.      Rustu Kaya      11/04/12 11:22      
   Idle Mode?      Joseph Hebert      11/04/12 13:46      
      RE: is there some special "idle mode" wrt the 805x hardware?        Andy Neil      11/05/12 00:34      
         Idle modes      Joseph Hebert      11/05/12 05:21      
   RE: couldn't get it into idle mode      Andy Neil      11/05/12 00:50      
      re:      Rustu Kaya      11/05/12 14:49      
         Check LST and try PD      Jim Granville      11/06/12 14:32      
   how do you know?      Erik Malund      11/05/12 07:20      

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