OK good point. Thanks for the reply. that is a very real possibility. Since the PIC chips are exactly the same I think it may be worth a try to save some money.
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OK good point. Thanks for the reply. that is a very real possibility. Since the PIC chips are exactly the same I think it may be worth a try to save some money.
Last edited by gopher; - 14th January 2008 at 05:15.
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I understand where you're coming from. But you got to look at it this way... without knowing all of the details of the revision, you may end up with a smoked board, and end up paying for a new one instead of an upgrade.... or whatever the details may be in your case. Hate to see that happen.
Wisdom is knowing what path to take next... Integrity is taking it.
Ryan Miller
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the thing is we got tons of extra old ones that will probably hit the trash if we decide to buy new
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Well... if you've got tons of old ones, hack away. That's my favorite way to learn about something. Personally, I'd desolder one of the old ones and see if the code protection fuses were blown, then inspect the circuit boards to see where the differences were. If the only differences is the serial connection, then chances are the manufacturer found a bug, fixed it, then thought to themselves.... hmmm what if this happens again? So they decide to flash it with a bootloader so they can send Joe customer a new revision that he can update himself instead of sending in a board, or buying a new one, etc. Sounds like you've got nothing to lose but time and sanity! Have fun with it.
Wisdom is knowing what path to take next... Integrity is taking it.
Ryan Miller
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You may be right. I might ask the techs to unsolder the chip from the new one, they have a nice hot air rework station. I did try unsoldering one of the old ones with a soldering iron, but its to hard to get all the pins heated evenly. Thanks again.
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Hi Gopher,
I noticed 9 holes on the front view. Alot of products in the alarm industry have either pads or holes for ICSP programming. It's possible that these holes might be for a tester or programmer. Try metering them to see if they connect to the ICSP pins on the PIC. Like you said, you've got alot of these boards. The RS232 chip could be for sending and receiving data and/or could be for a bootloader as was mentioned earlier.
HTH,
BobK
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ok here is what i traced
max232 pins 2,5 (INVALID, FORCEON) goes to PIC pin 30 (RC0/T1OSO/T13CKI)
max232 pin 4 (T1IN TTL/CMOS Transmitter Outputs) goes to PIC oun 31 (RC6/TX/CK)
max232 pin 6 (R1OUT TTL/CMOS Receiver Outputs) goes to PIC pin 32 (RC7/RX/DT)
does this sound like it makes any sence? can USART pins be used to program a part of the chips memory ?
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