PIC Microcontroller PIC Start Plus Programmer

May randomly do an uncommanded set of the Code Protect bit in the 17C44 JW and 17C756 and 17C756A windowed eprom parts. Contact Jim Robertson or Walter Quitt

Using the Picstart Plus for ICSP of a PIC16F873 or PIC 16F84

http://www.microchip.com/10/Tools/PICmicro/Program/picstart/psfw201/index.htm PICSTART Plus Firmware Update Date: 4/22/99 Software Version: 2.01 Notes:   This version of the PICSTART Plus firmware addresses a bug which on some Picstart Plus systems would program the first location of a 17Cxx device incorrectly. To update, follow the instructions in the README.PLS file.

http://www.microchip.com/10/Tools/PICmicro/Program/picstart/trouble/index.htm Microchips Troubleshooting Guide for PICSTART Plus

Q: I have had progressive difficulties with the programmer characterized by a message from MPLAB instructing me to check the power and serial connections and/or reset. It seems to help if I power down the programmer between chips

A: William K. Borsum, P.E. of OEM Dataloggers and Instrumentation Systems, San Diego, California, USA says

Is it a real microchip unit? The "real" power supply is NOT a wall wart--and is about 2" square and 3-4 inches long with a standard computer power cord connection to the wall plug--and the usual cylindrical plug on the other end. Part number PTF0905I? Be sure you received the right power supply!!!! The real ones are rated 100-240 VAC, 50-60Hz in at 0.3 A--9VDC out at 0.5 A. Says so--right on the label. Also UL and GS approvals. And they put out a clean regulated 9.0 volts according to my meter and scope.

I've been told by a reliable source that uChip shipped a bunch of wall warts at one point, and have been getting a lot of failures from them--I know mine failed--and the radio shack variety would not work at all.

From personal experience I know that the Picstart really wants 9.0 volts to work reliably. Input power will over-ride the internal DC-DC converter that generates the programming voltage (about 12-13 volts). IF the wall wart puts out 17 volts or more--as most cheap nominal 9-12 volt units do--then the pic being programmed is going to see that voltage. NOT good. Good news is that the picstart will most likely not be damaged.

If this is a recently shipped new unit, and it doesn't have the real uChip power supply--call uChip and get the right one! There should be No Charge from uChip--although the may want the old unit back.

Oh yes--there are other problems that can cause un-reliable programming and communications with the picstart via MPLAB. In may case I think it is tied to the lousy job uSoft has done with their comm-port drivers, and possibly motherboard problems as well. Try bringing up all the hardware from a cold power down condition with NO other software running (particularly background stuff like virus checkers)--then bring up mplab--then connect the picstart and initialize. Also, try the same procedure on a second PC. If it doesn't work then, something serious is probably wrong. Also, I am staying with MPLAB 12.12.00--newer versions give me problems.

There is a known problem with the PS+ programming the 16F87x family. The suggested work around: To reprogram a PIC16F87x with current PICSTART Plus software (as of 20000524), first program just the configuration bits with Code Protect enabled. PICSTART Plus will then recognize the chip as being code protected, and the chip can be reprogrammed successfully.

Questions:

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• jankspam at datacomm.ch asks:

  Hi, this is one maybe trivial questuin but I can't find any solution in manuals. " after compiling I know that my hex file is 0x100 long and I wont that Programmer automaticaly programing only from start =0 to end =0x100 " is there any assembler or linker direcive ? Thank You ... Nino

  PICList post "ICP" (Programming only a range on address)

See:

Ryan J Cocks Says:

I fixed my problem programming the 16F877s - it was a typo in the truers.asm on the CD for Predko's book - it XORs the last thing onto the __CONFIG, thus completely trasing it to an unfortunate value which turns on the code protection :-(

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