Electronics > Microcontrollers

Does blank HCS08 micro default to xtal osc?

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Circlotron:
Got an older board that I have to update to HCS08 micros. Several micros on the board. The first has a crystal oscillator and the osc output feeds the next micro osc input and so on. That all works fine because these older micros are programmed externally then plugged into a socket on the board. The newer ones though will be programmed in circuit.

What about the newer HCS08 micros? If any particular micro is blank, will the osc section still feed the clock signal to the next micro? I ask this because these micros have the option of using a given pin as an xtal osc connection or as a GPIO. What is the default for a blank chip?

dbator:
Hello,

did you find the answer? If not, what is the P/N of the HCS08 you asked?

Circlotron:
  No, I never found, but turns out it didn’t matter for several reasons. If I programmed the micros in the order they received the clock signal it would probably have been okay. Or they might actually use their internal oscillator during programming. Don’t know. I ended up using a 4MHz oscillator module and fed that to an inverter, then fanned out to four inverters, then sent the clock on its way to the micros.

The micro I used was a 9S08PA16. Not many people here seem to use S08 micros, it would appear. Me using those and assembly language makes help thin on the ground.

pgo:
This is definitely necromancy!

For what it is worth - HCS08 are usually reset into special mode for programming and default to the internal clock source.  The clock may be reprogrammed to a higher speed to speed up communication but would not use the crystal since its frequency would be unknown to the programmer.

bye

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