Hello, Thank you Myke for your information. I am aware of the simulator 'approximations'. I have't seen a simulator for a processor that works exacltly as the processor itself. Still I think it must be possible to make one ... I do have another, hopefully more interresting, question for this piclist. Is there a difference in interrupt latency time when using the TMR0 as interrupt generator? I personally don't think so because the TMR0 expires always at a known time synchronised to the clock, but I'm not sure. By the way: I'm using the PIC16C84. Greetings to you all: ... Sipke ... At 08:48 29/03/96 EST, you wrote: >Sipke, > >I haven't seen a lot of other people reply to your request yet, but I will >add my two cents on this. > >I have found that any simulator is going to give you an approximation of >what's going to happen. I went through similar problems when I did my code >for reading a TV I/R Remote Control. My first version, best case, only had >four instruction cycles before the next edge would come in. > >This turned out to be too close and even though MPSIM indicated that there >wasn't any problems, I found a bunch. (Which translates to mean the program >couldn't read anything coming through.) > >My solution was to re-order the program so that I would have 40-50 cycles >before the next expected interrupt. At this point, the program worked fine >and correlated to the simulator. > >In the databooks that I have, interrupt latency seems to vary when the edge >is received in the instruction timing. This may be what you're seeing here; >the simulator doesn't accurately handle at what point the interrupt happens. > >I don't think this is a Microchip problem, I have seen the same thing on >other simulators I have used. The only way you can be absolutely sure that >everything will work down to individual instructions is to use an emulator >pod (which costs mucho). I have found the best way to ensure your interrupt >driven programs work correctly is to leave lots of "space" before and after >your expected interrupts. > >The only analogy I can think of is in terms of Cp and CpK in manufacturing >processes. Make sure that your code can handle input irregardless of >whether or not the signals come in when you expect. Plot out when you >expect them, then give a few instructions on either side and design your >program to work right in the middle of that range. > >Sorry I can't be of more help, > >Myke > >>Return-Path: >>X-Sender: sdle@ensae >>Date: Thu, 28 Mar 1996 14:39:29 +0100 >>Reply-To: pic microcontroller discussion list >>Sender: pic microcontroller discussion list >>From: Sipke de Leeuw >>Subject: my mpsim problems >>To: Multiple recipients of list PICLIST >>X-UIDL: f1ddf1a5569c441a66c2568944079114 >> >>Hello you all, >> >>First off all: sorry when this message is sended twice to you. It won't happen >>again! >> >>I am new on the piclist group. I have some trouble with the MPSIM simulator. >>A discussion is going on between me and Microchip, but they don't seem to be >>able to help me. Can someone help me ?? >> >>The conversations with Microchip are below ... >> >Myke > >"We're Starfleet officers, weird is part of the job." > >Capt. Catherine Janeway > >