4.4.1.2 Application CPU running

[Tom Chiang]

Hi,

I found I_APPCPU3 is 0.3mA higher than I_APPCPU5. I have no idea. How come CPU consumes more power utilizing HFXO64M, an external oscillator 64MHz, than utilizing  a basic 32 MHz crystal?

[Turbo J]

Only an external 32 MHz crystal is supported for the high frequency clocks, see the OSCILLATORS chapter in the PS.

APPCPU5 runs code on the internal 64MHz oscillator, which consumes less current but is also not nearly as stable as a crystal. Thus the 0.3mA difference for APPCPU3 is just running from crystal vs. running from internal oscillator (HFINT64M).