MK60DX256 Crystal doesn't startup

[rabbit]

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

[apanecatl]

Hi Samuel, I recommend you change the XTAL oscillator components to:

C= 20-27pF

R=10M

[rabbit]

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

[apanecatl]

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.

[rabbit]

I try several combinations, the external 16Mhz oscilation doesn't exist.

1. The crystal is good part, because I swap crystal with crystal at an other product (MCU is not from Freescale), the 16Mhz exists in the other product.
2. Remove both load capacitor(Connection1), only the crystal connected to XTAl and EXTAL, no 16Mhz oscillation.
3. Add 10Mohm resistor with crystal (Connection 2), no 16Mhz oscillation.

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