89C51ED2
in [Design]
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From: krw on 8 Sep 2008 18:22 In article <48C23E59.BACAA685(a)hotmail.com>, rabbitsfriendsandrelations(a)hotmail.com says... > > > 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 ? He didn't say he could maintain *your* lousy code. It does take some talent to write maintainable code, in any language. > ASM is for twits, the clueless, poor and morons mainly AFAICS. No, twits shouldn't use it. Neither should dumb donkeys, evidently. > I don't mind checking the asm output of PL/M to see how it's done it though. Never been > unsatisfied. There is nothing wrong with PL/M, other than there is hasn't been support for it for a quarter century. There is nothing inherently wrong with assembler, particularly for the 8051, either. -- Keith
From: MooseFET on 8 Sep 2008 22:33 On Sep 8, 9:45 am, Eeyore <rabbitsfriendsandrelati...(a)hotmail.com> wrote: > MooseFET wrote: > > This is all in ASM so the overhead is just the LCALL and RET. > > Cor Blimey ! If you chose a certain optimise level in PL/M it'll use CALLs instead > of LCALLs if it can to save a few us. How do you propose to save any time that way? Thy both take 24 clocks to do. > > Graham
From: MooseFET on 8 Sep 2008 22:36 On Sep 9, 6:22 am, krw <k...(a)att.bizzzzzzzzzz> wrote: > In article <%LUwk.38434$Fr1.3...(a)newsfe03.iad>, > jamie_ka1lpa_not_valid_after_ka1l...(a)charter.net says... > > > > > TT_Man wrote: > > > >>>>Hmmm that's not how to code 8051 inrterrupts. > > > >>>Huh?????? > > > >>>Do you mean that you don't save the interrupted context???? !!!!! > > > >>I can't remember my reason for saying that now. Flags perhaps ? > > > >>Anyway PL/M handles all that for one. Declare procedure interrupt ! > > > >>Graham > > > > Coding in assembler opens all sorts of clever trick possibilities that HLL > > > guys would never have dreamed of. That only comes with years of developing > > > RT asm code. Why push a couple of status bytes when they can be saved in > > > half the time by moving them to registers in the current bank.......... > > > Doesn't work for everyone though...... > > > I guess that would be fine if you didn't have any higher priority INT's > > There are only two (levels). It doesn't take too much imagination > to figure out how to keep them from stepping on one another. Even in the ones with more levels, it isn't rocket surgery. You just keep a list of what is used by who. > > > doing the same thing or calling functions with in that block that are > > also doing the same thing. > > Remember, the 8051's stack is also quite limited. I've worked on machines with stacks of less than 16 calls. Compared to that, the 8051 stack is positively roomy. > > -- > Keith
From: Eeyore on 8 Sep 2008 23:45 krw wrote: > rabbitsfriendsandrelations(a)hotmail.com says... > > Joerg wrote: > > > Rich Grise wrote: > > > > 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? > > > > > > This is done all the time. First time I used the PCON features on a > > > 88C51 was in the early 90's. You have to make sure it does a controlled > > > wake up (socks, shoes, brush teeth, etc.) and know the time it takes. > > > When you build analog/RF stuff where there needs to be radio silence > > > you've got no other choice. > > > > And IIRC, the recent iterations of 8051 variants have improved the sleep etc > > function. It used to be almost useless. > > I used the sleep function on the 87FC51 in the late '80s without too > much trouble (after finding that the databook was wrong). I only > used it under battery power where my interrupt latency wasn't a > problem (it only had to do intrusion alarm and housekeeping stuff). > > I rather liked the 8051, though assembler was the only way to fly on > such a weird architecture. Did you ever try PL/M ? Graham
From: Eeyore on 8 Sep 2008 23:47
krw wrote: > rabbitsfriendsandrelations(a)hotmail.com says... > > Joerg wrote: > > > Eeyore wrote: > > > > > > > > And IIRC, the recent iterations of 8051 variants have improved the sleep etc > > > > function. It used to be almost useless. > > > > > > It was not useless. I sucessfully used it in the early 90's and that one > > > is still in production. Same code as the old code. > > > > Yeah, but back then is was DRAM, now it's static. You can rely on variables still > > being there. Plus I think they introduced a 'snooze' mode. > > Nonsense. I never met an 8051 that used dynamic logic. RAM The original was NMOS. > The thing is tiny. How old is your data book ? Graham |