CPU MC9S08AC16 clock out of range

[Spookydude]

Processor Expert error says my external crystal is out of range.  The MCU Specification Manual says I can go as high as 40Mhz with an external crystal.  The error says that the limit is 8Mhz however in the error message it states the range is 0-40Mhz butr it only gives me an option up to 8Mhz.  I want to use a 22.1184Mhz crystal oscillator.  How can I make this work?

[rocco]

Hi Spooky,

The difference in specs has to do with the difference between a crystal and an oscillator. The first sentence of your post states that you are using a crystal, but later you state that you are using an oscillator.

The AC16's internal oscillator circuitry can only drive a crystal up to 8 mHz. But the AC16 can accept an external clock up to 40 mHz. So an external oscillator of 22.1184 mHz should work.

What I can't help you with is how to tell Processor Expert whether you have a crystal or an external clock. That seems to be a separate problem.

[ProcessorExpert · Accepted solution]

Hello,

for more detals about settings of ICG module please see “Table A-11. ICG Frequency Specifications“ table in MC9S08AC16 datasheet (in Apendix A). I have also checked behaviour of AC16 CPU component and I think that it behaves according to this table and the PE documentation. Attached screen-shot shows how to set the CPU component to run from 22.1184 MHz oscillator.

best regards
Vojtech Filip
Processor Expert Support Team