18F2431 won't program or erase.

[keithdoxey]

Keith,
I found the info about the resistor in the file hlpPSPlus.chm in the ...MPLAB IDE\PicStartPlus folder. I tried with only the resistor and it SEEMED to work but I'll try to actually put a real file in it when I get home.

Thanks Henrik, found it now...

PICSTART Plus Limitations for PIC18F2331/2431
All power supply (Vdd and AVdd) and ground (Vss and AVss) pins must be used in order for these devices to program. PICSTART Plus will handle Vdd, Vss and AVss properly, but you must place a 1kOhm resistor between Pin 7 (AVdd) and Pin 11 in the socket with the device for proper operation. There are other devices that may require the use of all power supply and ground pins. Consult the datasheet if an unexplained programming problem occurs, such as inconsistent programming.

In your original mention of the resistor you said "between pin 7 (AVdd) and pin 11 (RC0)". the help file just mentions "Pin 11" rather than "RC0"

Looking at the pinout of the 4431, pin 11 is actually AVdd so I wonder if the resistor is because power is supplied to the wrong pins. Also the help file does not mention problems with the 4431 which also wouldnt program for me

Will experiment tonight.

Hi,Keith

Have a look here :http://www.mbtronics.com/picxx.asp

Thanka Alain but I already have the upgrade fitted.

[mister_e]

I confirm the 1K to RC0 + 1uF on Vdd/Vss (ONLY) stuff work

ICSP work as well without any care of the resistor on RC0... just the PGM pin must be loaded to GND.

Well spotted!

Another Picstart problem solved

[HenrikOlsson]

Keith,
OK, I have now tried to program my 18F2431 with the resistor only (no caps) fitted between pin 7 and 11 which is AVdd and RC0/T1OSO/T1CKI on the 28pin parts and I'm happy to report that it works - at least here. I also managed to get the QEI module counting my quadrature encoder, yes....

I added the labels (AVdd & RC0) in my original post because I thought it was strange and I didn't understand what it was supposed to do there. Perhaps it is as as you say that when programming a 2431 power is applied to pin 11 (which is power for 4431) instead of pin 7 and the resistor feeds it to pin 7. But then again, why doesn't your 4431 program? To bad I don't have any to test with, sorry.

Let us know what you find.

/Henrik Olsson.

[keithdoxey]

One is NOT amused

What version of MPLAB are you guys running ?

I am on 7.30 and non of the "successful" methods have worked for me.

I have just logged a support ticket with Microchip to see if they have any answers.

[HenrikOlsson]

Hi Keith,
Sorry to hear it's not working for you. I'm using the latest version of MPLAB, v7.42 and the PICStart version is 4.40.01. Do you get the same result as before, even with the resistor/cap? Still can't even erase/blank check it?

Is it on a 2431 or are you trying with the 4431?

When I flashed the 2431 with the MicroCodeLoader .hex file I had to change the config for the brown out voltage. Apparently the BOD was set to on but the trip voltage wasn't specified so it complained about that. Other than that it programed and verified without further problems.

I've searched the docs further but beyond the resistor and/or cap "solution" I haven't found anything. It'll be interesting to here what Microchip says.

/Henrik Olsson.

[keithdoxey]

Sorry to hear it's not working for you. I'm using the latest version of MPLAB, v7.42 and the PICStart version is 4.40.01.

OK. Will download 7.42 and see if that makes a difference

Do you get the same result as before, even with the resistor/cap? Still can't even erase/blank check it?

Everything is identical to the initial attempt at programming. Havent tried to Erase/Blank check. Just tried programming. Will also try that

Is it on a 2431 or are you trying with the 4431?

Both, and multiple devices

When I flashed the 2431 with the MicroCodeLoader .hex file I had to change the config for the brown out voltage. Apparently the BOD was set to on but the trip voltage wasn't specified so it complained about that. Other than that it programed and verified without further problems.

Yes, I got those messages as well. I initially DISABLED BOD with no success, then I tried leaving it enabled but setting the voltage to 4.2V still no success.

I've searched the docs further but beyond the resistor and/or cap "solution" I haven't found anything. It'll be interesting to here what Microchip says.

I spent a long time googling and searching the mchip forum to no avail.

The only reason I have those chips is because I want them for the QEI interface and now my project has hit another delay just because I cant get the bootloader files into the bloody chips

You have now caused me untold grief as I was blissfully unaware of the problem until you suffered from it !! I'm not really blaming you though as I would have hit this problem anyway, its just annoying that both you and Steve have got it to work and I cant

[keithdoxey]

Hi All,

just got the following reply from Microchip....

Could you please try out the following when you receive the message:
"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 disabled before proceeding.."

Proceed to Programmer Menu -> Settings
There deselect ( don't select) Auto Memory Areas and Range.
Manually enter memory areas and range as follows:
Program Memory Start Address : 0
Program Memory End Address : 3fff
Select Program Memory
Select Configuration Bits
Select ID Locations
Select EEPROM Data
Select Erase All Before Program

Then try programming. Programming will take a while since the entire memory range is being programmed.

In addition try out the following:
Short the Vdd and AVdd pins of the microcontroller. Also separately short the Vss and AVss pins of the microcontroller. Now connect the capacitor between Vdd and Vss pins.
Ensure that the capacitor that you're connecting between Vdd and Vss is a low ESR capacitor such as tantalum. Start with 0.1uF value and if programming failures still arise, try increasing this value incrementally to a maximum of 10uF.

Will give that a try this evening to see if I get any success.