18F2431 won't program or erase.

[HenrikOlsson]

Hi everybody,

I got a couple of 18F2431 (samples) I was going to play with. First I realised I had to update my PBP. Then, with that covered I had to update my PicStartPlus firmware. There I discovered that I had to order the PUM-unit from Microchip to retrofit my 1996 model PicStartPlus and now, when I finaly have everything covered they won't program - go figure....

I'm trying to flash it with the MicroCodeLoader firmware 18F2431_20.hex file that from the MCSP\MCLoader\LoaderHEX folder but no matter what I do it errors out on me when verifying, saying that loads of the configuration bits not are what they're supposed to be. As well as some of the program memory locations are bad.

I've tried to erase the device but then when blank-checking it says that it's not blank, Program memory and data memory.

I tested with a 18F4550 and it works perfect with it's corresponding .hex file.

I *would* have guessed it's a bad part if it wasn't for the fact that I've got three and they all acts the same way.

Anybody used this device? Any ideas why it won't program or even erase correctly?

I'm using MPLab7.42 with the latest PICStart firmware.

Thank you in advance for whar ever advice you may have.

/Henrik Olsson.

[keithdoxey]

Is the power supply OK to the PICStart Plus ?

I havent loaded my 4550s yet as the version of MPlab on the machine I was using didnt support them but I will give it a try.

Oops... just noticed you said 2431. I have some 2431s and 4431s so will also try them.

[HenrikOlsson]

Hi Keith,
I haven't checked the power but since the 4550's program OK I'd dare to say it's probably fine. If you get a chance to test your 2431's I'd appreciate it!

Thanks!
/Henrik Olsson.

[keithdoxey]

Hi Henrik

Bad news Im afraid. I updated this machine to MPLab 7.30 and my programmer says PICSTART Plus Firmware Version 4.40.1.

Tried the 18F2431 and 18F4431 and failed with all three chips of each type.

I couldnt find the 4550s after putting them somewhere safe when I tidied up the other day but did find something else that I had lost ^H^H^H^H put away safely

Successfully programmed 3 18F4520s with no hesitation.

Now the bad bit. A Googling session gave me the following information....

from http://forum.microchip.com/tm.aspx?m=189398

I have also had trouble programming the 18F2431 on Tech-Tools programmers. They (Tech Tools) have confirmed the problem, but have no solution. They are removing this part from the list of compatible parts from their list. They say that the Microchip programming equipment does not program this part.


from http://forum.microchip.com/tm.aspx?m=107927

The 18Fxx31 and several other devices in this family require the use of a capicitor between Vdd and Vss to slow down the rise time. Some will not Erase, thus will not program if not blank. PM 3 is also subject to this problem.

This workaround can be found in the Readme for PicStart Plus but has been further updated to include other devices that were found to have this problem:

Some devices require that a 0.1uF bypass capacitor be placed
from the VDD pin to the VSS pin of the device to successfully
program the device. If programming failures still arise,
try increasing this value incrementally to a maximum of 10uF.
The parts affected are:

PIC16F737 PIC16F747 PIC16F767 PIC16F777
PIC18F1220 PIC18F1320 PIC18F2220 PIC18F2320
PIC18F2331 PIC18F2431 PIC18F2410 PIC18F2420
PIC18F2455 PIC18F2480 PIC18F2510 PIC18F2515
PIC18F2520 PIC18F2525 PIC18F2550 PIC18F2580
PIC18F2585 PIC18F2610 PIC18F2620 PIC18F2680

For devices such as the 18Fxx31 which have power supply (Vdd and AVdd)
and ground (Vss and AVss), all pins must be used in order for these
devices to program.

Now the REALLY BAD NEWS.....

tried all that and it still didnt work. I started off with a 100nF cap on each set of supply pins and that didnt work so went the whole hog and stuck 4.7uF on each set of pins. At that point I got the following error message when I tried to program.

Program Memory or EEPROM Data is protected. Reprogram
the entire part. If "Auto select memory areas and range"
on the Memory Ranges tab of the programmer settings
is enabled, it must be disabeled before proceeding..

Removing the caps took me back to the original "going through the motions" before failing verification. Decided to go a bit more gently with the caps and used a 1.0uF. Still failed. Added a 100nF as well... still failed.

Decided to go for a 2.2uF and got the "protected" message again.

Reverted to the smaller caps and checked the voltages while programming. 4.97v on one set of pins, 5.01 on the other set. Wasnt sure if this was because only one set were powered and the lower voltage was fed through the PIC so I removed it and attempted to check the voltages.

Without a PIC you instantly get the "protected" message again but I did see a breif change on the multimeter on both sets of pins.

Dont know what to do now

[keithdoxey]

For devices such as the 18Fxx31 which have power supply (Vdd and AVdd) and ground (Vss and AVss), all pins must be used in order for these devices to program.

Reverted to the smaller caps and checked the voltages while programming. 4.97v on one set of pins, 5.01 on the other set. Wasnt sure if this was because only one set were powered and the lower voltage was fed through the PIC so I removed it and attempted to check the voltages.

Had another thought after posting that. Maybe the different voltages on the two sets of pins could have been causing a problem so I connected them together and stuck 1.0uF on there as well. Still didnt work

[mister_e]

Did you also tried ICSP too?

I have the same problem with PICSTART on this device here too. But not on another programmer.

I'll send a mail NOW to their tech-support to know if there's a known working solution.