Rob Hamerling wrote: > > > funlw65 wrote: >> Hmm, guys you forgot about this: >> >> assembler >> -- ======================== >> bsf _status, _rp0 -- bank 1 >> -- ======================== >> call 0x3ff -- get the factory calibrated OSC value >> movwf osccal -- for accurate timing >> -- ================== >> bcf _status, _rp0 -- bank 0 >> -- ================== >> end assembler > > You are right that OSCCAL should be loaded with the calibrated value in > that high-memory location. And not only for the 2 PICs you mention, but > also for a number of others. I have a note in my todo list: 10Fs, > 12F508,509,510,519,629,675 and 16F505,506,630,676, maybe more. > > I think a simple 'asm movwf OSCCAL' as very first instruction will be > enough, because with a reset the program counter is set to the last > memory location (e.g. DS41239D 4.7.1 and 9.2.2). > > Changing OSCCAL is fine tuning, omitting OSC calibration will not be the > cause that a led doesn't blink at all, only the blink frequency may be a > bit different. > > When an accurate frequency is a required an external oscillator is the > way to go. > > We have discussed the OSCCAL issue in the begin-period of the Jallib > group and decided then to spend out time on more urgent things. >
Rob I have been having a problem with, what I thought was with baud rate, in a test file using the internal clock of the 16f628a. I noticed that there was no OSCCAL in the device file. Not knowing for sure if that (or me) was a problem, I grep'ed the svn device files for OCSCAL. I come up with 289 devices with no OSCCAL in the files and 306 that have OSCCAL in them. Thought I must be mistaken as I did not realize you had done 'that' many (595) devices, I just put it into my notes and continued to see if I could get this k107 working. Up till then I had been using 2 & 3 Terminal resonators but order some 20Mhz xtals Monday to see if maybe that is my problem. Live & learn. Regards Wayne >> Should be included in device file for 12F629 and 12F675. > > And in some others, if in the device files at all. It requires > co-operation with the compiler, because the compiler decides where code > is store in memory. Maybe it should be a pragma. > >> Also, you >> must pay attention at burning time, to not override that location of >> flash memory.... > > True, use a proper programmer! > > Regards, Rob. > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "jallib" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/jallib?hl=en -~----------~----~----~----~------~----~------~--~---
