Post by thread:[EE]: 16F876 EEPROM Problems Still

Hi All, Last week I asked about writing more than 1 byte to the 'F876 eeprom causing me problems. I've tried polling the WR bit and also using the write-complete interrupt with no difference. The only way I can get the chip to program more than 1 location in succession is to insert a small delay (12ms) after each write. Any further ideas would be appreciated. I wrote a small routine that writes 8-1 into eeprom locations 8-1 to prove the fault wasn't in another area - it shows the same fault. (only writes 8th loc'n) Below is the code I'm using for the eeprom write: ee_write: ; bank2 ;bank 2 movwf eeadr ;set up eeprom address bank3 ;bank 3 bcf gie ;disable the global interrupt bcf eepgd ;make it a data eeprom write bsf wren ;enable eeprom writing movlw h'55' ; movwf eecon2 ;eeprom write unlock sequence movlw h'aa' ; movwf eecon2 ;eeprom write unlock sequence bsf wr ;initiate data eeprom write bcf wren ;disable the eeprom writing bank0 ;bank 0 ee_wait: btfsc wr ;is the eeprom finished writing? goto ee_write ;no bsf gie ;re-enable the global interrupt return ;exit Regards... -- http://www.piclist.com hint: To leave the PICList spam_OUTpiclist-unsubscribe-requestTakeThisOuTmitvma.mit.edu

David Duffy wrote: > bsf wren ;enable eeprom writing > movlw h'55' ; > movwf eecon2 ;eeprom write unlock sequence > movlw h'aa' ; > movwf eecon2 ;eeprom write unlock sequence > bsf wr ;initiate data eeprom write > bcf wren ;disable the eeprom writing This last line probably kills the write routine. Try leaving WR set until the write is completed. -- Best regards Tony mICro's http://www.picnpoke.com .....salesKILLspam@spam@picnpoke.com -- http://www.piclist.com hint: To leave the PICList piclist-unsubscribe-requestKILLspammitvma.mit.edu

Tony wrote: >David Duffy wrote: > > bsf wren ;enable eeprom writing > > movlw h'55' ; > > movwf eecon2 ;eeprom write unlock sequence > > movlw h'aa' ; > > movwf eecon2 ;eeprom write unlock sequence > > bsf wr ;initiate data eeprom write > > bcf wren ;disable the eeprom writing > > >This last line probably kills the write routine. > >Try leaving WR set until the write is completed. I put the wrong version in my last email - corrected one is; ;****************************************************************************** ;* 'ee_write' writes one byte. * ;* enter with eeprom address in w and eeprom data in eedata (bank 2). * ;****************************************************************************** ee_write: ; bank2 ;bank 2 movwf eeadr ;set up eeprom address bank0 ;bank 0 ew_busy: ; btfsc ee_busy ;is the eeprom busy from a previous write? goto ew_busy ;yes, loop & wait bcf gie ;no, disable the global interupt bank3 ;bank 3 bcf eepgd ;make it a data eeprom write bsf wren ;enable eeprom writing movlw h'55' ; movwf eecon2 ;eeprom write unlock sequence movlw h'aa' ; movwf eecon2 ;eeprom write unlock sequence bsf wr ;initiate data eeprom write bank0 ;bank 0 bsf ee_busy ;set flag to say eeprom is busy bsf gie ;re-enable the global interupt return ;exit If I put a 12ms delay in just before the return it works ok. I'm now clearing the WREN bit in the interrupt routine. My flag (ee_busy) is also cleared in the same spot. Regards... -- http://www.piclist.com hint: To leave the PICList .....piclist-unsubscribe-requestKILLspam.....mitvma.mit.edu

David Duffy wrote: > If I put a 12ms delay in just before the return it works ok. > I'm now clearing the WREN bit in the interrupt routine. > My flag (ee_busy) is also cleared in the same spot. > Regards... Have you tried simulating the code with MPASM? The EEPROM write function is supported. That may provide a clue. -- Best regards Tony mICro's http://www.picnpoke.com EraseMEsalesspam_OUTTakeThisOuTpicnpoke.com -- http://www.piclist.com hint: To leave the PICList piclist-unsubscribe-requestspam_OUTmitvma.mit.edu

David: See my comments at ##### in the code. Been there done EXACTLY that :-( David Duffy wrote: {Quote hidden}> > Tony wrote: > >David Duffy wrote: > > > bsf wren ;enable eeprom writing > > > movlw h'55' ; > > > movwf eecon2 ;eeprom write unlock sequence > > > movlw h'aa' ; > > > movwf eecon2 ;eeprom write unlock sequence > > > bsf wr ;initiate data eeprom write > > > bcf wren ;disable the eeprom writing > > > > > >This last line probably kills the write routine. > > > >Try leaving WR set until the write is completed. > > I put the wrong version in my last email - corrected one is; > > ;****************************************************************************** > ;* 'ee_write' writes one byte. * > ;* enter with eeprom address in w and eeprom data in eedata (bank 2). * ##### Instead put the data in a tempory location. I will call ##### it "EETemp" > ;****************************************************************************** ##### Make sure that your banks are correct. They sound wrong to me. > ee_write: ; > bank2 ;bank 2 > movwf eeadr ;set up eeprom address ##### This store writes over the previous value that is being ##### used to write to the EEPROM if two writes are done quickly. ##### Storing the data ahead of the test for the EEPROM being ##### ready will causes the same problem. > bank0 ;bank 0 > ew_busy: ; > btfsc ee_busy ;is the eeprom busy from a previous write? > goto ew_busy ;yes, loop & wait ##### Do the stores after the EEPROM is ready ##### Set the bank ##### Bank2 ##### movwf eeadr ;set up eeprom address ##### Now Store the data ##### movf EETemp,W ##### movwf eedata {Quote hidden}> bcf gie ;no, disable the global interupt > bank3 ;bank 3 > bcf eepgd ;make it a data eeprom write > bsf wren ;enable eeprom writing > movlw h'55' ; > movwf eecon2 ;eeprom write unlock sequence > movlw h'aa' ; > movwf eecon2 ;eeprom write unlock sequence > bsf wr ;initiate data eeprom write > bank0 ;bank 0 > bsf ee_busy ;set flag to say eeprom is busy > bsf gie ;re-enable the global interupt > return ;exit > > If I put a 12ms delay in just before the return it works ok. > I'm now clearing the WREN bit in the interrupt routine. > My flag (ee_busy) is also cleared in the same spot. > Regards... > > -- > http://www.piclist.com hint: To leave the PICList > @spam@piclist-unsubscribe-requestKILLspammitvma.mit.edu -- http://www.piclist.com hint: PICList Posts must start with ONE topic: [PIC]:,[SX]:,[AVR]: ->uP ONLY! [EE]:,[OT]: ->Other [BUY]:,[AD]: ->Ads