68hc12 | EEPROM not readable on reset? (MC68HC912B32)

Hey. Is there an initialization sequence necessary to be able to read EEPROM (byte-erasable) on reset? Here's my situation: MC68HC912B32 microcontroller. 1. The first line of my program clears COPCTL. 2. The next several lines copy bytes from EEPROM (starting at $0D00) into RAM (starting at $0800). 3. The program is located in flash EEPROM at $8000 4. The reset vector at $FFFE is pointed to $8000. 5. On power-on the program does not work. 6. Through the BDM when I specify that the program starting at $8000 should run, it does so fine. 7. However when not in BDM, on power on or external reset, the program does not run. 8. If I remove the lines that copy data from EEPROM (byte-erasable) to RAM and reflash the EEPROM, the program runs fine on power on and when reset externally with and without the BDM. Thus, it seems that I am missing some kind of init routine to make $0D00-$0FFF readable. Any ideas?

Reply by drranu ●August 2, 20052005-08-02

Hey Dave, thanks a lot for the reply. The very first thing the code does is shut down COP though. And when I remove the copy routine from the code, it works fine outside of BDM. --- In 68HC12@68HC..., Dave Perreault <dap@p...> wrote: > I would guess that the additional copy code generates enough delay that > you are not getting to your code which disables the COP. In BDM mode the > COP starts up disabled. > > Dave > drranu wrote: > > > Hey. Is there an initialization sequence necessary to be able to read > > EEPROM (byte-erasable) on reset? Here's my situation: > > > > MC68HC912B32 microcontroller. > > > > 1. The first line of my program clears COPCTL. > > 2. The next several lines copy bytes from EEPROM (starting at $0D00) > > into RAM (starting at $0800). > > 3. The program is located in flash EEPROM at $8000 > > 4. The reset vector at $FFFE is pointed to $8000. > > 5. On power-on the program does not work. > > 6. Through the BDM when I specify that the program starting at $8000 > > should run, it does so fine. > > 7. However when not in BDM, on power on or external reset, the > > program does not run. > > 8. If I remove the lines that copy data from EEPROM (byte-erasable) > > to RAM and reflash the EEPROM, the program runs fine on power on and > > when reset externally with and without the BDM. > > > > Thus, it seems that I am missing some kind of init routine to make > > $0D00-$0FFF readable. Any ideas? > > > > > > > > > > > > > > > > SPONSORED LINKS > > Intel microprocessors > > <http://groups.yahoo.com/gads?t=ms&k=Intel+microprocessors&w1=Intel+microprocessors&w2=Pic+microcontrollers&w385+microprocessor&c=3&sx&.sig=B_gglo6oPjfvny4MR50mJg> > > Pic microcontrollers > > <http://groups.yahoo.com/gads?t=ms&k=Pic+microcontrollers&w1=Intel+microprocessors&w2=Pic+microcontrollers&w385+microprocessor&c=3&sx&.sig=xUhmC5G81SCtcJV6x7qsWg> > > 8085 microprocessor > > <http://groups.yahoo.com/gads?t=ms&k85+microprocessor&w1=Intel+microprocessors&w2=Pic+microcontrollers&w385+microprocessor&c=3&sx&.sig=4tuA5VR_gFWoruiF9v6hVg> > > > > > > > > > > >. > > > > > > > >

Reply by Dave Perreault ●August 2, 20052005-08-02

I would guess that the additional copy code generates enough delay that you are not getting to your code which disables the COP. In BDM mode the COP stats up disabled. Dave drranu wrote: > Hey. Is there an initialization sequence necessary to be able to read > EEPROM (byte-erasable) on reset? Here's my situation: > > MC68HC912B32 microcontroller. > > 1. The first line of my program clears COPCTL. > 2. The next several lines copy bytes from EEPROM (starting at $0D00) > into RAM (starting at $0800). > 3. The program is located in flash EEPROM at $8000 > 4. The reset vector at $FFFE is pointed to $8000. > 5. On power-on the program does not work. > 6. Through the BDM when I specify that the program starting at $8000 > should run, it does so fine. > 7. However when not in BDM, on power on or external reset, the > program does not run. > 8. If I remove the lines that copy data from EEPROM (byte-erasable) > to RAM and reflash the EEPROM, the program runs fine on power on and > when reset externally with and without the BDM. > > Thus, it seems that I am missing some kind of init routine to make > $0D00-$0FFF readable. Any ideas? > > > SPONSORED LINKS > Intel microprocessors > <http://groups.yahoo.com/gads?t=ms&k=Intel+microprocessors&w1=Intel+microprocessors&w2=Pic+microcontrollers&w385+microprocessor&c=3&sx&.sig=B_gglo6oPjfvny4MR50mJg> > Pic microcontrollers > <http://groups.yahoo.com/gads?t=ms&k=Pic+microcontrollers&w1=Intel+microprocessors&w2=Pic+microcontrollers&w385+microprocessor&c=3&sx&.sig=xUhmC5G81SCtcJV6x7qsWg> > 8085 microprocessor > <http://groups.yahoo.com/gads?t=ms&k85+microprocessor&w1=Intel+microprocessors&w2=Pic+microcontrollers&w385+microprocessor&c=3&sx&.sig=4tuA5VR_gFWoruiF9v6hVg > > > >. > >

Reply by Dave Perreault ●August 2, 20052005-08-02

Both the RAM and the EEPROM should be visible at startup of the B32 part. What does your copy code look like and what are you using to generate it? Dave Dave Perreault wrote: > I would guess that the additional copy code generates enough delay that > you are not getting to your code which disables the COP. In BDM mode the > COP starts up disabled. > > Dave > drranu wrote: > > > Hey. Is there an initialization sequence necessary to be able to read > > EEPROM (byte-erasable) on reset? Here's my situation: > > > > MC68HC912B32 microcontroller. > > > > 1. The first line of my program clears COPCTL. > > 2. The next several lines copy bytes from EEPROM (starting at $0D00) > > into RAM (starting at $0800). > > 3. The program is located in flash EEPROM at $8000 > > 4. The reset vector at $FFFE is pointed to $8000. > > 5. On power-on the program does not work. > > 6. Through the BDM when I specify that the program starting at $8000 > > should run, it does so fine. > > 7. However when not in BDM, on power on or external reset, the > > program does not run. > > 8. If I remove the lines that copy data from EEPROM (byte-erasable) > > to RAM and reflash the EEPROM, the program runs fine on power on and > > when reset externally with and without the BDM. > > > > Thus, it seems that I am missing some kind of init routine to make > > $0D00-$0FFF readable. Any ideas? > > > > > > > > > > > > > > > > SPONSORED LINKS > > Intel microprocessors > > > <http://groups.yahoo.com/gads?t=ms&k=Intel+microprocessors&w1=Intel+microprocessors&w2=Pic+microcontrollers&w385+microprocessor&c=3&sx&.sig=B_gglo6oPjfvny4MR50mJg > <http://groups.yahoo.com/gads?t=ms&k=Intel+microprocessors&w1=Intel+microprocessors&w2=Pic+microcontrollers&w385+microprocessor&c=3&sx&.sig=B_gglo6oPjfvny4MR50mJg>> > > > Pic microcontrollers > > > <http://groups.yahoo.com/gads?t=ms&k=Pic+microcontrollers&w1=Intel+microprocessors&w2=Pic+microcontrollers&w385+microprocessor&c=3&sx&.sig=xUhmC5G81SCtcJV6x7qsWg > <http://groups.yahoo.com/gads?t=ms&k=Pic+microcontrollers&w1=Intel+microprocessors&w2=Pic+microcontrollers&w385+microprocessor&c=3&sx&.sig=xUhmC5G81SCtcJV6x7qsWg>> > > > 8085 microprocessor > > > <http://groups.yahoo.com/gads?t=ms&k85+microprocessor&w1=Intel+microprocessors&w2=Pic+microcontrollers&w385+microprocessor&c=3&sx&.sig=4tuA5VR_gFWoruiF9v6hVg > <http://groups.yahoo.com/gads?t=ms&k85+microprocessor&w1=Intel+microprocessors&w2=Pic+microcontrollers&w385+microprocessor&c=3&sx&.sig=4tuA5VR_gFWoruiF9v6hVg>> > > > > > > > > > > > >. > > > > > > > > > SPONSORED LINKS > Intel microprocessors > <http://groups.yahoo.com/gads?t=ms&k=Intel+microprocessors&w1=Intel+microprocessors&w2=Pic+microcontrollers&w385+microprocessor&c=3&sx&.sig=B_gglo6oPjfvny4MR50mJg> > Pic microcontrollers > <http://groups.yahoo.com/gads?t=ms&k=Pic+microcontrollers&w1=Intel+microprocessors&w2=Pic+microcontrollers&w385+microprocessor&c=3&sx&.sig=xUhmC5G81SCtcJV6x7qsWg> > 8085 microprocessor > <http://groups.yahoo.com/gads?t=ms&k85+microprocessor&w1=Intel+microprocessors&w2=Pic+microcontrollers&w385+microprocessor&c=3&sx&.sig=4tuA5VR_gFWoruiF9v6hVg > > > >. > >

Reply by Jefferson Smith ●August 2, 20052005-08-02

--- In 68HC12@68HC..., "drranu" <drranu@y...> wrote: > Hey Dave, thanks a lot for the reply. The very first thing the code > does is shut down COP though. And when I remove the copy routine from > the code, it works fine outside of BDM. > I had this problem. I found the solution is to reset the COP just before disabling it (mine is MC68HC912BC32, but probably the same with COP). --jeffs

Reply by drranu ●August 2, 20052005-08-02

Dave, actually I have a simpler case. I set the reset vector to point to $8000. From here, the code shuts off the COP watchdog and then jumps to $0FFA in EEPROM which just jumps to $8100 which then runs sime very simple code to continuously output an 'e' on the SPI port (which goes to a RS-232 level converter for a serial port). Again, unless the BDM is on, it won't work. Here's the code: org $8000 clr COPCTL jmp $0FFA org $8100 clr SC0CR1 movw #$000C,SC0CR1 ldaa SC0SR1 ldab #$65 LOOP: jsr PUT_CHAR bra LOOP PUT_CHAR: brclr SC0SR1,#$80,PUT_CHAR stab SC0DRL rts Okay, now at $0FFA there is just ldy #$8100 jmp 0,Y And that's all. It will not run on power on or external reset without the BDM connected and on (controlled from a host proc). Thanks for any help. All of my programs to date (3 years worth) have run fine until I started accessing the EEPROM. Thanks for any help. I really appreciate your time. --- In 68HC12@68HC..., Dave Perreault <dap@p...> wrote: > Both the RAM and the EEPROM should be visible at startup of the B32 part. > > What does your copy code look like and what are you using to generate it? > > Dave > Dave Perreault wrote: > > > I would guess that the additional copy code generates enough delay that > > you are not getting to your code which disables the COP. In BDM mode the > > COP starts up disabled. > > > > Dave > > > > > > drranu wrote: > > > > > Hey. Is there an initialization sequence necessary to be able to read > > > EEPROM (byte-erasable) on reset? Here's my situation: > > > > > > MC68HC912B32 microcontroller. > > > > > > 1. The first line of my program clears COPCTL. > > > 2. The next several lines copy bytes from EEPROM (starting at $0D00) > > > into RAM (starting at $0800). > > > 3. The program is located in flash EEPROM at $8000 > > > 4. The reset vector at $FFFE is pointed to $8000. > > > 5. On power-on the program does not work. > > > 6. Through the BDM when I specify that the program starting at $8000 > > > should run, it does so fine. > > > 7. However when not in BDM, on power on or external reset, the > > > program does not run. > > > 8. If I remove the lines that copy data from EEPROM (byte-erasable) > > > to RAM and reflash the EEPROM, the program runs fine on power on and > > > when reset externally with and without the BDM. > > > > > > Thus, it seems that I am missing some kind of init routine to make > > > $0D00-$0FFF readable. Any ideas? > > >

Reply by Dr. David A. Perreault ●August 3, 20052005-08-03

If this is all you have, where did you setup the stack pointer? Dave drranu wrote: > Dave, actually I have a simpler case. I set the reset vector to point > to $8000. From here, the code shuts off the COP watchdog and then > jumps to $0FFA in EEPROM which just jumps to $8100 which then runs > sime very simple code to continuously output an 'e' on the SPI port > (which goes to a RS-232 level converter for a serial port). Again, > unless the BDM is on, it won't work. Here's the code: > > org $8000 > clr COPCTL > jmp $0FFA > > org $8100 > clr SC0CR1 > movw #$000C,SC0CR1 > ldaa SC0SR1 > ldab #$65 > LOOP: > jsr PUT_CHAR > bra LOOP > > PUT_CHAR: > brclr SC0SR1,#$80,PUT_CHAR > stab SC0DRL > rts > > Okay, now at $0FFA there is just > ldy #$8100 > jmp 0,Y > > And that's all. It will not run on power on or external reset without > the BDM connected and on (controlled from a host proc). Thanks for > any help. All of my programs to date (3 years worth) have run fine > until I started accessing the EEPROM. Thanks for any help. I really > appreciate your time. > > --- In 68HC12@68HC..., Dave Perreault <dap@p...> wrote: > > Both the RAM and the EEPROM should be visible at startup of the B32 > part. > > > > What does your copy code look like and what are you using to > generate it? > > > > Dave > > > > > > Dave Perreault wrote: > > > > > I would guess that the additional copy code generates enough delay > that > > > you are not getting to your code which disables the COP. In BDM > mode the > > > COP starts up disabled. > > > > > > Dave > > > > > > > > > drranu wrote: > > > > > > > Hey. Is there an initialization sequence necessary to be able to > read > > > > EEPROM (byte-erasable) on reset? Here's my situation: > > > > > > > > MC68HC912B32 microcontroller. > > > > > > > > 1. The first line of my program clears COPCTL. > > > > 2. The next several lines copy bytes from EEPROM (starting at > $0D00) > > > > into RAM (starting at $0800). > > > > 3. The program is located in flash EEPROM at $8000 > > > > 4. The reset vector at $FFFE is pointed to $8000. > > > > 5. On power-on the program does not work. > > > > 6. Through the BDM when I specify that the program starting at > $8000 > > > > should run, it does so fine. > > > > 7. However when not in BDM, on power on or external reset, the > > > > program does not run. > > > > 8. If I remove the lines that copy data from EEPROM (byte-erasable) > > > > to RAM and reflash the EEPROM, the program runs fine on power on and > > > > when reset externally with and without the BDM. > > > > > > > > Thus, it seems that I am missing some kind of init routine to make > > > > $0D00-$0FFF readable. Any ideas? > > > > SPONSORED LINKS > Pic microcontrollers > <http://groups.yahoo.com/gads?t=ms&k=Pic+microcontrollers&w1=Pic+microcontrollers&w2=Intel+microprocessors&w385+microprocessor&c=3&sx&.sig=trd8G9Fjoj7JJ3faqzNL9w> > Intel microprocessors > <http://groups.yahoo.com/gads?t=ms&k=Intel+microprocessors&w1=Pic+microcontrollers&w2=Intel+microprocessors&w385+microprocessor&c=3&sx&.sig=K9F-qweX-SR3HNRrl-g3yw> > 8085 microprocessor > <http://groups.yahoo.com/gads?t=ms&k85+microprocessor&w1=Pic+microcontrollers&w2=Intel+microprocessors&w385+microprocessor&c=3&sx&.sig=Gy6INN6xGz43y8XfYFnyxw > > > >. > >

Reply by E E ●August 3, 20052005-08-03

Jeffereson, thanks for your reply. On your suggestion I tried doing that as well as properly resetting the COP in the program at the right intervals to no avail. Hmm... --- Jefferson Smith <imajeffs@imaj...> wrote: > --- In 68HC12@68HC..., "drranu" > <drranu@y...> wrote: > > Hey Dave, thanks a lot for the reply. The very > first thing the code > > does is shut down COP though. And when I remove > the copy routine from > > the code, it works fine outside of BDM. > > > > I had this problem. I found the solution is to reset > the COP just > before disabling it (mine is MC68HC912BC32, but > probably the same with > COP). > --jeffs > __________________________________________________

Reply by E E ●August 3, 20052005-08-03

Dave, my apologies. I neglected to copy that line over. "lds #$0BFF" is placed right after "clr COPCTL". I also tried Jefferson's suggestion of resetting COP (with the $55, $AA sequence into COPRST) prior to clearing COPCTL and even added resetting COP at the right times in the program, to no avail. It seems that unless I'm using BDM, reading from (byte erasable) EEPROM changes something so that the program doesn't run. Incidently, COPCTL is defined as $0016 and COPRST is $0017. Am I missing something? --- "Dr. David A. Perreault" <dap@dap@...> wrote: > If this is all you have, where did you setup the > stack pointer? > > Dave > drranu wrote: > > > Dave, actually I have a simpler case. I set the > reset vector to point > > to $8000. From here, the code shuts off the COP > watchdog and then > > jumps to $0FFA in EEPROM which just jumps to $8100 > which then runs > > sime very simple code to continuously output an > 'e' on the SPI port > > (which goes to a RS-232 level converter for a > serial port). Again, > > unless the BDM is on, it won't work. Here's the > code: > > > > org $8000 > > clr COPCTL > > jmp $0FFA > > > > org $8100 > > clr SC0CR1 > > movw #$000C,SC0CR1 > > ldaa SC0SR1 > > ldab #$65 > > LOOP: > > jsr PUT_CHAR > > bra LOOP > > > > PUT_CHAR: > > brclr SC0SR1,#$80,PUT_CHAR > > stab SC0DRL > > rts > > > > Okay, now at $0FFA there is just > > ldy #$8100 > > jmp 0,Y > > > > And that's all. It will not run on power on or > external reset without > > the BDM connected and on (controlled from a host > proc). Thanks for > > any help. All of my programs to date (3 years > worth) have run fine > > until I started accessing the EEPROM. Thanks for > any help. I really > > appreciate your time. > > > > --- In 68HC12@68HC..., Dave Perreault > <dap@p...> wrote: > > > Both the RAM and the EEPROM should be visible at > startup of the B32 > > part. > > > > > > What does your copy code look like and what are > you using to > > generate it? > > > > > > Dave > > > > > > > > > Dave Perreault wrote: > > > > > > > I would guess that the additional copy code > generates enough delay > > that > > > > you are not getting to your code which > disables the COP. In BDM > > mode the > > > > COP starts up disabled. > > > > > > > > Dave > > > > > > > > > > > > drranu wrote: > > > > > > > > > Hey. Is there an initialization sequence > necessary to be able to > > read > > > > > EEPROM (byte-erasable) on reset? Here's my > situation: > > > > > > > > > > MC68HC912B32 microcontroller. > > > > > > > > > > 1. The first line of my program clears > COPCTL. > > > > > 2. The next several lines copy bytes from > EEPROM (starting at > > $0D00) > > > > > into RAM (starting at $0800). > > > > > 3. The program is located in flash EEPROM > at $8000 > > > > > 4. The reset vector at $FFFE is pointed to > $8000. > > > > > 5. On power-on the program does not work. > > > > > 6. Through the BDM when I specify that the > program starting at > > $8000 > > > > > should run, it does so fine. > > > > > 7. However when not in BDM, on power on or > external reset, the > > > > > program does not run. > > > > > 8. If I remove the lines that copy data > from EEPROM (byte-erasable) > > > > > to RAM and reflash the EEPROM, the program > runs fine on power on and > > > > > when reset externally with and without the > BDM. > > > > > > > > > > Thus, it seems that I am missing some kind > of init routine to make > > > > > $0D00-$0FFF readable. Any ideas? > > > > > > > > > > > > > > > > > SPONSORED LINKS > > Pic microcontrollers > > > <http://groups.yahoo.com/gads?t=ms&k=Pic+microcontrollers&w1=Pic+microcontrollers&w2=Intel+microprocessors&w385+microprocessor&c=3&sx&.sig=trd8G9Fjoj7JJ3faqzNL9w> > > > Intel microprocessors > > > <http://groups.yahoo.com/gads?t=ms&k=Intel+microprocessors&w1=Pic+microcontrollers&w2=Intel+microprocessors&w385+microprocessor&c=3&sx&.sig=K9F-qweX-SR3HNRrl-g3yw> > > > 8085 microprocessor > > > <http://groups.yahoo.com/gads?t=ms&k85+microprocessor&w1=Pic+microcontrollers&w2=Intel+microprocessors&w385+microprocessor&c=3&sx&.sig=Gy6INN6xGz43y8XfYFnyxw> > > > > > > > > > > > > >. > > > > > > > > > [Non-text portions of this message have been > removed] __________________________________

Reply by E E ●August 4, 20052005-08-04

Okay, so here's my assessment of the problem: With the idea that Jefferson had about needing to reset the COP timer right before shutting it off (clr COPCTL), I thought that perhaps by reading byte erasable EEPROM (BE-EEPROM), COP is turned on, despite having turned it off. And since COPCTL is a write-once register, if it comes back on, I can't turn it off again. So, during my initial access to BE-EEPROM, I reset the COP timer several times then following the last read, I turn off the COP timer. This way, it doesn't time out and since I'm done reading the BE-EEPROM, COPCTL isn't automatically modified. It sounds crazy this whole thing, but several simple programs on three different board designs with different B32s verify that reading of the BE-EEPROM will turn on COP, no matter its previous state. Thus, turning it off AFTER reading BE-EEPROM keeps COP off. Right now, my program does not run on power-on reset, but will after an external reset, with or without BDM. I can handle that, but that's goofy. The same program without the reading of BE-EEPROM works on power-on reset however. It appears to be a bug in the processor. If Freescale wants code that demonstrates this, I'll be happy to share it. Thanks goes to Jefferson whose suggestion generated my solution. __________________________________________________

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EEPROM not readable on reset? (MC68HC912B32)

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