topic Re: In-System Programming in 8-bit Microcontrollers

In-System Programming

afro — Thu, 02 Feb 2006 07:06:23 GMT

Hello

How do you switch 6 lines at a time which are used to programming uC? I don't know how can I run my programs with programmer which is connected to uC.

Thank you for your reply.

Re: In-System Programming

Nabla69 — Thu, 02 Feb 2006 18:47:03 GMT

Yo,

FOR HCO8, not S08:

If the programmer is plugged, you don't usually run the application.
However, you need to be able to drive the pins properly to talk with it.
A regular way is to use the pins in the application as outputs, so the outside circuitry is not supposed to drive them and your programmer will be able to drive them.
If you want to be completly on the safe side, keep PTA0 free. This is the pin used to transmit all commands & data. Other pins are just used for configuration.
You could also put jumpers on your board to disconnect the outside circuitry from the pins when you are using the programmer.

If you use an internal oscillator (ICG), make sure you still can impose a clock on multiplexed CLK pins for programming.

Does it help ??
Alvin.

Re: In-System Programming

afro — Thu, 02 Feb 2006 19:32:52 GMT

Thank your for your reply.

I switch lines with CD4053 (Triple 2-channel analog multiplexer), but what about runnin programms. If I switched off programmer, my programms doesn't run. What's wrong? In programming I use External Clock Generator and in User Mode I have External oscillator and doesn't connect IRQ pin.

I use HC908GP32

Re: In-System Programming

Nabla69 — Thu, 02 Feb 2006 20:02:14 GMT

No prob Afro, u're welcome.

In your soft, make sure you're RESET Vector is pointing to the start of your software or initialization routine (start08.c on CodeWarrior).

Also, put a 4.7kΩ to 10kΩ pull-up resistor on both RESET and IRQ pin. As you need 5V on RESET pin to get out of Reset.

You can also check if the Oscillator runs with a scope (it may stop it though if you don't use a low capacitance probe which cost 1.5k€).

Alvin.

Re: In-System Programming

afro — Thu, 02 Feb 2006 21:10:22 GMT

Now it is OK. I used too low tuning capacitor in external oscillator.

Thank you for your time.

Good luck!