Post by thread:16F873 runs slower than 16F84

Greetings all!, I am trying out my old 16F84 programs on my new 16F873 set up, everything seems to be working ok except the 16F873 is running slightly slower than the 16F84 (using a very similar program). The program is a simple led flash program that also sends out a test message (bit banged 16F84 style) to the PC. If you watch the leds flashing on the two circuits you can see after a few seconds that the 16F873 setup is running just a little slower than the 16F84 but the big difference is in the test message to the PC, the 16F873 is printing garbage. I have tried a different 16F873 but it does just the same thing, any ideas?, is there some extra feature on the 16F873 that could be causing this? (I have turned off WDT and DEBUG). ------- John P.B. ----- John P. Brown spam_OUTJ.P.BrownTakeThisOuTbradford.ac.uk ---- \ --- Witty remark goes here --- / --------------------------------------------------

Puzzle solved!, the two programs below are identical at source level but the 16F873 version compiles to a bigger .hex program. I am using cc5x so I re-compiled using the -a option and on examination of the .asm listing I could see that all the timing loops are longer due to some extra BCF instructions in the compiled 16F873 version (for ram paging I think). I recalculated my time loop constants and now the both run at the same speed :-) On Wed, 17 May 2000, JP.BROWN wrote: {Quote hidden}> Greetings all!, I am trying out my old 16F84 programs on my new 16F873 set > up, everything seems to be working ok except the 16F873 is > running slightly slower than the 16F84 (using a very similar program). > > The program is a simple led flash program that also sends out a test > message (bit banged 16F84 style) to the PC. If you watch the leds flashing > on the two circuits you can see after a few seconds that the 16F873 setup > is running just a little slower than the 16F84 but the big difference is > in the test message to the PC, the 16F873 is printing garbage. > > I have tried a different 16F873 but it does just the same thing, any > ideas?, is there some extra feature on the 16F873 that could be causing > this? (I have turned off WDT and DEBUG).