Email: Password: Remember Me | Create Account (Free)

Back to Subject List

Old thread has been locked -- no new posts accepted in this thread
???
03/02/05 12:46
Read: times


 		 #88864 - More A5 opcode info
Responding to: ???'s previous message
so I'll reveal my sources, too!

The Intel 8XC251SB Embedded Microcontroller User’s Manual includes a description of how they use the A5 opcode as an "escape" to extend the instruction:

http://www.intel.com/design/mc...261701.pdf

In particular, Table A-6 on page A-4 (PDF page 231) shows the Instructions for MCS® 51 Microcontrollers - and gives opcode A5 the name ESC

The Triscend E5 datasheet says, "The E5 supports an op-code 'A5' instruction, which was not available on the original 8032. This is a software breakpoint function."

I s'pose it depends on exactly how closely individual variants have followed the Intel design as to what this opcode will actually do in any particular variant.

As Jez has looked at the VHDL of some 8051 implementations, perhaps he can comment on what goes on "under the bonnet (hood)"...?

List of 43 messages in thread
TopicAuthorDate
Kitchen Drain .. Unwanted Features            01/01/70 00:00      
   13-bit Mode for Timers            01/01/70 00:00      
   Dumb A5 Opcode            01/01/70 00:00      
      0xA5 opcode            01/01/70 00:00      
         Finally room for XOR C,bit :)            01/01/70 00:00      
            MOV bit,bit            01/01/70 00:00      
      CY flag            01/01/70 00:00      
         My A5 source information....            01/01/70 00:00      
            More A5 opcode info            01/01/70 00:00      
            0xA5 is derivative-depend            01/01/70 00:00      
      Oh no it doesn't            01/01/70 00:00      
   Inverted wishlist            01/01/70 00:00      
      Inverted wishlist            01/01/70 00:00      
         wishlist II.            01/01/70 00:00      
            Loadsa XRAM!            01/01/70 00:00      
               Don't believe all you see...            01/01/70 00:00      
                  because of the taste of vanilla            01/01/70 00:00      
                     chocolate chips            01/01/70 00:00      
                  Unbelievable!            01/01/70 00:00      
            Ridiculous MOVC addressing modes...            01/01/70 00:00      
               MOVC            01/01/70 00:00      
               MOVC Designer.....Your Fired !!            01/01/70 00:00      
      Errr then it's not an 8051 then!            01/01/70 00:00      
         Is it then 8051            01/01/70 00:00      
         AVR???            01/01/70 00:00      
      wishlist continued            01/01/70 00:00      
         low power at slow clock            01/01/70 00:00      
            low power            01/01/70 00:00      
               i am confused!            01/01/70 00:00      
                  But I thought they ARE CMOS!            01/01/70 00:00      
                     quiescent            01/01/70 00:00      
   what I definitely do not want            01/01/70 00:00      
      Right architecture            01/01/70 00:00      
         some of us do bits a bit fast            01/01/70 00:00      
            I know but...            01/01/70 00:00      
               all things to all people            01/01/70 00:00      
                  erics last post            01/01/70 00:00      
         RIght Achitecture???            01/01/70 00:00      
      So what do you think about...            01/01/70 00:00      
         ADC/DAC will live forever!            01/01/70 00:00      
            That guy?            01/01/70 00:00      
               Stick            01/01/70 00:00      
   Ability of changing return from interupt            01/01/70 00:00      

Back to Subject List