908QT4 User Monitor

[Autotecnic]

Hello everyone, i made demonstartion board for 908QT4 as per AN2305 fig1. Also programmer as described in Datasheet Fig15-10 - page 140. This is monitor mode circuit with external oscilator and high voltage.

I use P&E Micro to program usermitor program from AN2305, then i program the M68DemoQTQY software. No errors during programing.

Then i take chip from programmer and put into demonstration board, Demo program works fine (led Blinks and so on) but when i close Sw1 to enter usermonitor i cant get to comunicate with P&E soft.

I swapped MAX232 chip from programmer to demo board same error, In comunication dialog box of P&E i get 1) Hardware loopback detected : Yes . All rest items are NO.

Anyone have an idea or can point me in the right direction ??

Thanks

[Autotecnic]

Hello, Thanks for your answers. To Mac, yes i tried both ways, after closing sw1 i do POR and nothing. i configure Class III board with 9600 baud but no comunication established. I also tried with other speeds and nothing, also tried with hyperterminal and i get the echo from the loopback but no response from chip (not even trash).

To "a", the document you mention EB16 refers to correct a problem with usermonitor soft that came preprogrammed in some demboards, but i got a blank part and made myself the circuit. So i downloaded the code from AN2305.

I also read the osctrim value as per AN2312, i found for my chip is 7EH, so i save at adress FFC0 cause user monitor uses this value as it runs on internal oscilator.. But again that did not work. So i run out of ideas.

Any help aprecciated.

Regards

[Nabla69]

Hello Autotecnic,

If you can program the part, you can access MON08.

The User Monitor is for user to use embedded flash programming routines = User accessing Monitor routines, am I right ?

May you please explain what you want to achieve ?

It could help me/us understand better.

Alberto.

[Autotecnic]

Thanks Alberto, it´s simpler than that, user mode monitor provides acces to monitor routines without requiring high voltage and external osc that would be required to enter normal monitor mode. This is very important in this low pin count chips, you only need one pin ,PTA0 for comunication. This is achieved by this small pogram that resides from adress FFB0 and monitors the state of PTA2 pin, if it´s low at power on then it jumps to $2CF9 wich is the mon08 SWI ISR for int osc. 

Better explained in AN2305.

Regards

Miguel

AN2305.pdf

Message Edited by t.dowe on 2009-09-16 10:19 AM

[Autotecnic]

Hello everyone, problem solved !!. It was my mistake as i was using 980QT4A not QT4 aside from other things this new version has changed internal rom routines, so ne adress are needed to get into those routines.

Just in case somoene would need attached is user mode monitor modified for QT4A.

Regards

[Alban]

Yo !

Thanks for keeping us posted (literally).
Much appreciated when subjects are neatly closed

Cheers,
Alban.

[bigmac]

Hello,

It is not clear from your post whether you do a POR while SW1 is closed.  My understanding of user mode monitor access is that, simply closing the switch does not gain access to monitor mode.

Regards,

Mac

[milan_madzarac]

Hi,

I had the same problem long time ago and
asked the same question, it should be somewhere on this forum.
The answer I got was fast but it did not help.
Then I found couple of month ago the document:
EB615: User Monitor CONFIG1 Register Error .
It is on the QT4 web page under Engineering Bulletins.
Probably that CONFIG1 is the reason for that behavior but I
did not like to waste time so I have never tried to fix it.

I switched to another controller.

Best regards,

Milan