1. Is it possible to test and trace K64 clocks using oscilloscope connected to test point?
2. What are the default clocks values for bare-metal MCU after the power up?
Of course, you can route the FlexBus clock to a pin so that you can test it with scope.You can deduce the core/cyctem clock from FlexBus clock frequency by checking the SIM_CLKDIV1 reg.
The FRDM-K64F uses MK64FN1M0VLL12 chip with 100 pin LQFP, the PTC3 is the CLKOUT pin.
This is the PTC3 function:PTC3/LLWU_P7/CMP1_IN1/SPI0_PCS1/UART1_RX/FTM0_CH2/CLKOUT/I2S0_TX_BCLK, the PTC3 is connected to pin16 of J1 connector on FRDM-K64F
I suppose you can use the code to configure the PTC3 as CLKOUT function:
SIM_SCGC5|=0x800; //enable GORTC gated clock
PORTC_PCR3|=0x500; //select ALT5
You can write the CLKOUTSEL bits to select the CLKOUT in SIM_SOPT2
SIM_SOPT2&=0xE0; //select FlexBus clock
Hope it can help you
CLKOUT select in section 12.2.3 System Options Register 2 (SIM_SOPT2) in RM of K64.
Selects the clock to output on the CLKOUT pin.000 FlexBus CLKOUT001 Reserved010 Flash clock011 LPO clock (1 kHz)100 MCGIRCLK101 RTC 32.768kHz clock110 OSCERCLK0111 IRC 48 MHz clock
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