89C51ED2
in [Design]
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From: Eeyore on 6 Sep 2008 04:20 MooseFET wrote: > "TT_Man" <Some...(a)ntlworld.com> wrote: > > ">>>> >> I think he said it was all written in asssembler <yuk>. > > > > >> > On an 8051, asm is really the way to go. The OP was making comments > > >> > about DPTR so I suspected asm but vagueness of his descriptions > > >> > sounded like a C programmer who doesn't really know what is going on > > >> > under the hood. Many C compilers overlay variables on the 8051 if he > > >> > is doing interrupts in C code he may be running a routine in the > > >> > interrupt code that overlays one of his variables. > > > > >> >> Graham > > > > >> Not a prayer in hell 100% assembler. :) > > > > > Are you using interrupts? > > > > Everything is interrupt driven. Processor spends 99% in sleep mode.Int > > routines set flags and the background processes flags, then goes back to > > sleep. Dual 3 of 5 uarts are processed with 125uS RTC. > > I think you need to look very carefully at the interrupt code to make > sure that it doesn't forget to save part of the context. This sounds > like it is either timing related or an uninitialized flag. Hmmm that's not how to code 8051 inrterrupts. Graham
From: Eeyore on 6 Sep 2008 04:22 MooseFET wrote: > On Sep 6, 5:30 am, Rich Grise <r...(a)example.net> wrote: > > On Fri, 05 Sep 2008 17:53:59 +0100, TT_Man wrote: > > > ">> > > >>> >> I think he said it was all written in asssembler <yuk>. > > > > >>> > On an 8051, asm is really the way to go. The OP was making comments > > >>> > about DPTR so I suspected asm but vagueness of his descriptions > > >>> > sounded like a C programmer who doesn't really know what is going on > > >>> > under the hood. Many C compilers overlay variables on the 8051 if he > > >>> > is doing interrupts in C code he may be running a routine in the > > >>> > interrupt code that overlays one of his variables. > > > > >>> Not a prayer in hell 100% assembler. :) > > > > >> Are you using interrupts? > > > Everything is interrupt driven. Processor spends 99% in sleep mode.Int > > > routines set flags and the background processes flags, then goes back to > > > sleep. Dual 3 of 5 uarts are processed with 125uS RTC. > > > > This raises a BIG red flag for me - how long does the uP take to come out > > of sleep mode? How's the interrupt latency? Did it used to block other > > interrupts, or could they be stepping on each other? > > 8051s have a built in interrupt lock out and priority system. I doubt > that he is getting into multiple levels of interrupts. LOL ! All too easy by half and don't forget you have only 4 register banks to play with, meaning only only 3 simultaneous interrupts. of various priorities. Graham
From: Eeyore on 6 Sep 2008 04:24 MooseFET wrote: > Eeyore wrote: > > MooseFET wrote: > > > Eeyore wrote: > > > > MooseFET wrote: > > > > > > > Is it written in ASM or C? > > > > > > I think he said it was all written in asssembler <yuk>. > > > > > On an 8051, asm is really the way to go. The OP was making comments > > > about DPTR so I suspected asm but vagueness of his descriptions > > > sounded like a C programmer who doesn't really know what is going on > > > under the hood. Many C compilers overlay variables on the 8051 if he > > > is doing interrupts in C code he may be running a routine in the > > > interrupt code that overlays one of his variables. > > > > I still use PL/M 51. So easy to use. You can treat it as highish level language and > > set a register directly in the next line. > > > > I can't even begin to imagine coding some of the fairly complex (for microcontrollers) > > stuff that we did with 8051s in asm. The mind boggles. Never mind code maintenance. > > I do it all the time. It takes less time to write the code than to > design it. Any competent engineer can maintain it. I'll send you some code shall I ? ASM is for twits, the clueless, poor and morons mainly AFAICS. I don't mind checking the asm output of PL/M to see how it's done it though. Never been unsatisfied. Graham
From: TT_Man on 6 Sep 2008 06:12 >>>> Not a prayer in hell 100% assembler. :) >>> >>> Are you using interrupts? >> Everything is interrupt driven. Processor spends 99% in sleep mode.Int >> routines set flags and the background processes flags, then goes back to >> sleep. Dual 3 of 5 uarts are processed with 125uS RTC. > > This raises a BIG red flag for me - how long does the uP take to come out > of sleep mode? How's the interrupt latency? Did it used to block other > interrupts, or could they be stepping on each other? > > But I've never trusted "sleep mode" - probably because it takes me about > 3 hours after getting up, before I'm fully awake. ;-) > > Do you have a little "morning eye-opener" circuit? ;-D > > Good Luck! > Rich > Latency is 1 instruction cycle.
From: TT_Man on 6 Sep 2008 06:14
> > LOL ! > > All too easy by half and don't forget you have only 4 register banks to > play > with, meaning only only 3 simultaneous interrupts. of various priorities. > > Graham > Not true, with careful innovative Int. structures |