Using internal clock (68HC908QYx)

[eckhard · Accepted solution]

Hello,

you can use the User Monitor, see AN2305. It works with P&E or Metrowerks tools and uses the internal Oscillator. You can load it into the flash memory with forced monitor mode on empty devices using the internal oscillator. The Problem is to get the Oscillator Trim value first. You can read the trim value while in forced monitor mode and update the user monit code to write the correct trim value. A better way is to trim the internal oscillator in your application. To do that you have to run a little program, look at AN2317. You have to program the flash to do so and the next time you can´t use forced Monitor mode to load the user monitor. I think P&E have a small programm to trim the oscillator that runs from ram.

Eckhard

[Brancaloneda_No]

Hi

Thank you a lot, I have read this application note and I will perform somme tests now.

Brancaléone

[Brancaloneda_No]

Hi

I would like to know if it is possible to use only the internal clock of the 68HC908QY4 (especially during download). In other words, I want to download program and use this microcontrolleur whitout quartz or external clock.

Thank you

Brancaléone