Programming the 18F2331 and 18F2431 devices

Post by **Steve** » Mon Mar 26, 2007 3:49 pm

Users may not be able to program the 18F2331 and 2431 devices using the EB006 or HP488 programmer boards. This is because pin 7 (AVdd) needs to be at 5V during programming.

One way around this is to hold switch SA5 (on the HP488) down during the programming cycle. EB006 users would need to put a switch board onto port A and hold switch 5 down instead.

mroppo · Post by **mroppo** » Tue Apr 03, 2007 8:12 pm

Would this fix apply to 18F458 series picks as we are having similar problems here at DeVry with the programmer.

MIKE ROPPO

Post by **Steve** » Wed Apr 04, 2007 8:38 am

Hello Mike,

This issue does not affect the 18F458, so it must be another problem. Are you having a problem with other types of PICmicro? If you are, then the board or installation of the software could be at fault.

If you are experiencing this problem only on the '458, then it could be the chip itself is damaged.

Please contact our tech support with specific details and we'll try to solve the problem.

Le~Funk~ · Post by **Le~Funk~** » Wed Apr 04, 2007 8:30 pm

The board we have is an eb-006. We have tried this on more than one board. We have tried this on multiple chips, as well. The configurations on the expert menu are basically set to Crystal XT, Watchdog Timer is off, Low Voltage Detect is on and OSC. Switch enable is Disabled. The Two board switches are set to XTAL and Fast. After Programming, Nothing really happens; our program never activates upon reset even though it says the programming was successful.

Post by **Steve** » Thu Apr 05, 2007 8:49 am

If the programmer says that programming was successful, then here are the possibilities:

* the oscillator circuitry on the board does not work

* the oscillator settings on the board do not match the oscillator settings in the config word

* the timing used within the program is inappropriate for the oscillator speed in the board

Please try some simple LED-based programs with a range of configuration settings to see if the problem occurs with only one type of oscillator.

Note also that if a crystal above 4MHz is used, then you need to use the "HS" crystal mode in the config word.

Post by **Benj** » Thu Apr 05, 2007 9:27 am

It may also be a power issue.

If you have enabled Low Voltage Programming you need to move a few of the jumpers on the board. EG J29 - USB and J11 - LVP.

If you are using a 12 - 14V external power supply then you will need J29 - PSU and J11 - I/O. You will also need to disable the Low Voltage programming option in PPP or Flowcode.

Lastly if you are using the 19.6608 MHz crystal then you must set the oscillator into HS mode. This must be copied on the the board by flicking the osc switch to XTAL. The config must be set up to use the external oscillator and external MCLR unless you want to use the internal hardware.

Now when you program the PICmicro you should see that it is running the program straight away.