Post by thread:Still PIC12C508A programming problems..

Hello list, I have some trouble programming a series of 12C508A chips, I have upgraded firmware on my picstart pluss from 1.20 to 2.01 as suggested by someone on this list. I am also using the latest mplab 4.12, running win98. My picstart pluss has serial nr: JIT965120923-R4 I think the problem is the internal osc. When I program my chips I always get an message "calibration data already programed" at the end. Also, when verifying, I always get an missmatch at 0000 (calibration data?) What is the correct use of the internal osc anyway ?? Is it really neccesary to calibrate the osccal register ?? Is the internal osc. different from different production series ?? PS! I have programed several 12c508a from other production series with same hex file without any problems.. Anyone have any ideas ?? best regards, tobias

Tobias wrote: > I think the problem is the internal osc. When I program my chips I always > get an message "calibration data already programed" at the end. Also, when > verifying, I always get an missmatch at 0000 (calibration data?) > Ignore the message on an OTP. You must tell the PIC in the first line where to get the calibration data, so you must have the following at the top of your code (from the 12C508 template): ORG 0x1FF ; processor reset vector ; Internal RC calibration value is placed at location 0x1FF by Microchip ; as a movlw k, where the k is a literal value. ORG 0x000 ; coding begins here movwf OSCCAL ; update register with factory cal value Check also that you do not use the 12C509's reset vector (0x03FF). Hope this helps Quentin

There needs to be one line of code following the ORG 0x1FF line MOVLW 0xnn ; where 0xnn is your osc. calibration value. You did record the original value didn't you? - Nick - Quentin wrote: {Quote hidden}> > Tobias wrote: > > > I think the problem is the internal osc. When I program my chips I always > > get an message "calibration data already programed" at the end. Also, when > > verifying, I always get an missmatch at 0000 (calibration data?) > > > Ignore the message on an OTP. > You must tell the PIC in the first line where to get the calibration > data, so you must have the following at the top of your code (from the > 12C508 template): > > ORG 0x1FF ; processor reset vector > ; Internal RC calibration value is placed at location 0x1FF by Microchip > ; as a movlw k, where the k is a literal value. > ORG 0x000 ; coding begins here > movwf OSCCAL ; update register with factory cal > value > > Check also that you do not use the 12C509's reset vector (0x03FF). > > Hope this helps > Quentin

Tobias, If you follow this you get rid of the problem: Picstart Plus -> Enable Programmer Picstart Plus -> Program/Verify Uncheck "Calibration Memory" Program and Verify from this window HŠlsningar/ Regards, Bjarne Nebelong Manager Electrical Design BINDOMATIC¨ spam_OUTbjarne.nebelongTakeThisOuTbindomatic.se <.....bjarne.nebelongKILLspam@spam@bindomatic.se> http://www.bindomatic.com <http://www.bindomatic.com> +46-(0)8 709 58 46 -----Ursprungligt meddelande----- FrŒn: Tobias [tobiasKILLspamEUNET.NO] Skickat: den 25 september 1999 13:59 Till: .....PICLISTKILLspam.....MITVMA.MIT.EDU €mne: Still PIC12C508A programming problems.. Hello list, I have some trouble programming a series of 12C508A chips, I have upgraded firmware on my picstart pluss from 1.20 to 2.01 as suggested by someone on this list. I am also using the latest mplab 4.12, running win98. My picstart pluss has serial nr: JIT965120923-R4 I think the problem is the internal osc. When I program my chips I always get an message "calibration data already programed" at the end. Also, when verifying, I always get an missmatch at 0000 (calibration data?) What is the correct use of the internal osc anyway ?? Is it really neccesary to calibrate the osccal register ?? Is the internal osc. different from different production series ?? PS! I have programed several 12c508a from other production series with same hex file without any problems.. Anyone have any ideas ?? best regards, tobias