Hi,
what are the drawbacks on setting XTAL field to 0x15 (as if I had a 16MHz crystal), but the actual crystal is 12.288MHz to have a system clock of 61.44MHz (I need a clock multiple of 12.288MHz)
best regards
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Hi,
what are the drawbacks on setting XTAL field to 0x15 (as if I had a 16MHz crystal), but the actual crystal is 12.288MHz to have a system clock of 61.44MHz (I need a clock multiple of 12.288MHz)
best regards
Perhaps I have not explained.
If I set XTAL to 0x12, I get a sysclock of 80MHz.
I need to generate 192KHz, 384KHz and 768KHz as exact as possible. I need 0% error. timers cannot generate those frequency with requested precision starting from 80MHz sysclock.
That's why I want to generate 61.44MHz sysclock. 61.44 = 5 x 12.288.
Another way is to use 24.576MHz crystal and bypass PLL.
best regards
mastupristi said:what are the drawbacks
How about instant loss of JTAG - resulting from mismatch between "actual xtal freq" and your xtal field SW entry.
It is inventive/clever idea - but don't believe tolerated by the Stellaris function. Your idea of 24.xxx MHz xtal - and entry of that value w/in xtal field - should work nicely...
Thank you - appreciated. However - not all Stellaris will accept > 20MHz xtal - be sure to check electrical specs. (your MCU datasheet)
We use M4F w/25 MHz xtal - works fine - but seem to recall earlier/lesser MCUs may not accept that high a Fxtal...