I have built two prototype board, it seems the crystal doesn't startup. I use 16Mhz crystal with two 10pF load capacitor, I use scope to check the waveform, there is no 16Mhz signal at EXTAL, the IAR debuuger stop at
"while (MCG_S & MCG_S_IREFST_MASK){}; // wait for Reference clock Status bit to clear".
I check the reference manual, in Chapter 26, it mention that "Rf" maybe required, but it doesn't say how much should be the value, 10M? 5M? ..
Regards
Samuel
Hi Samuel, I recommend you change the XTAL oscillator components to:
C= 20-27pF
R=10M
I put 10M resistor, still the same, without 16Mhz signal.
This is a new board, without program the MCU.
My question is: is the external clock by default on? or need enable the external clock by softwrae?
Regards
Samuel
If the mcu has not been programmed the MCG is not configured, thus the XTAL will not start up, you need to program the mcu and configure the MCG for this to happen.
I try several combinations, the external 16Mhz oscilation doesn't exist.
The MCU is from Freescale sample IC, I am not sure something wrong with those IC or there is some requirement of crystal?
Regards
Samuel