topic Re: MC9S08GT60 SCM. in 8-bit Microcontrollers

MC9S08GT60 SCM.

Aliester — Fri, 11 Jul 2008 03:58:14 GMT

Hello, I am using the MCU MC9S08GT60 and I can't communicate with the hyperterminal using the serial.
I was using the baud rate register to set the frequency, but the terminal only get garbage. So I ask here if someone can give me a little code on how to set the right baud rate using the SCM mode to produz a 9600 baud rate.

Thank you in advance for any help.

Re: MC9S08GT60 SCM.

peg — Fri, 11 Jul 2008 05:54:19 GMT

Hello and welcome to the fora, Aliester,

In order to help you with this we would need to know what clock you are using.
Do you have an external oscillator or crystal or are you using the internal clock.
If you are using the internal clock, are you trimming it properly.

Download AN2494 from this site as it will help you greatly with this setup.
It is an interactive spreadsheet that helps with all the clock setup.

Re: MC9S08GT60 SCM.

Aliester — Mon, 14 Jul 2008 19:33:41 GMT

I am communicating with the hyperterminal but a just receive garbage.
I used even the processor expert to set the baud rate to the transmission (9600) but I keep getting trash (not all the time).
So after reading in a manual I am trying to discover how to obtain the internal oscillator frequency, if there is a pin to measure it.
Thank you in advance.

Re: MC9S08GT60 SCM.

Aliester — Mon, 14 Jul 2008 20:09:15 GMT

BTW,

I am using a SARD board (MC13192) with a MC9S08GT60CFB MCU
Thanks for any help.

Re: MC9S08GT60 SCM.

Aliester — Mon, 14 Jul 2008 21:47:39 GMT

The board I was using was "busted". When I got another board the same program worked without a problem.
Now I saw, one board has a "04/26" numeration, while the other have a "04/27".
Any ideas?
Thank you in advance.

Re: MC9S08GT60 SCM.

peg — Tue, 15 Jul 2008 03:19:21 GMT

Hi,
Possibly you are running of the internal oscillator and it is not trimmed.
It is possibly the working board is very close to correct and works OK without any trim whereas the first one needs trimming to be good enough for serial comms.
With a SARD you would normally use the clock from the radio though.

Re: MC9S08GT60 SCM.

Aliester — Tue, 15 Jul 2008 03:36:59 GMT

Hello, can you explain to me how do I do this "trim" you are taking?
Thank you for your time.

Aliester.

Re: MC9S08GT60 SCM.

peg — Tue, 15 Jul 2008 17:12:34 GMT

Hi Aliester,

To do that easily I need to know how you are programming your device.
Perhaps you are using Codewarrior on a PC and connecting via a P&E USB Multilink?
Let us know.

Re: MC9S08GT60 SCM.

Aliester — Tue, 15 Jul 2008 20:14:09 GMT

Hello Peg.
I am doing exacty as you said, I am using codeWarrior and a usb multilink to load the boards.
Thanks for your help.

Re: MC9S08GT60 SCM.

peg — Wed, 16 Jul 2008 03:08:00 GMT

Hi,

Here is one reference.
Basically you tell your programmer to do it for you. It will burn the value in to flash at NVTRIM $FFBE.
Your programme must transfer this value to ICGTRM $4E upon every reset.
Note this only applies if you are using the ICG internal clock.
There are many other references on how to do this in this forum.

Re: MC9S08GT60 SCM.

Aliester — Wed, 16 Jul 2008 21:07:36 GMT

Hi peg.

I did like in the other thred but it did'nt work for one of the boards, maybe it's broken after all?
Thanks.