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Diffstat (limited to 'docs/library')
| -rw-r--r-- | docs/library/pyb.rst | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/docs/library/pyb.rst b/docs/library/pyb.rst index d221e9720..8bb08215b 100644 --- a/docs/library/pyb.rst +++ b/docs/library/pyb.rst @@ -103,6 +103,18 @@ Power related functions supported and the largest supported frequency not greater than the given sys_freq will be selected. + Supported frequencies are (in MHz): 8, 16, 24, 30, 32, 36, 40, 42, 48, + 54, 56, 60, 64, 72, 84, 96, 108, 120, 144, 168. + + 8MHz uses the HSE (external crystal) directly and 16MHz uses the HSI + (internal oscillator) directly. The higher frequencies use the HSE to + drive the PLL (phase locked loop), and then use the output of the PLL. + + Note that if you change the frequency while the USB is enabled then + the USB may become unreliable. It is best to change the frequency + in boot.py, before the USB peripheral is started. Also note that + frequencies below 36MHz do not allow the USB to function correctly. + .. function:: wfi() Wait for an interrupt. |