I am trying to use a 16 Mhz external oscillator for both the CPU clk and the BUSCLK, but am having difficulty in getting it to operate correctly. The reason for wanting to use the external oscillator is so that no trimming of the internal clock would be required.
Using the internal clock, some chips exhibit baud rate errors without trimming. I tried to use the initializer, to use the FBE mode, but the debug module fails displaying "frequency change to ~0 hz, repeatedly.
The setting from the initializer that works is
ICGC1 = 0x46
ICGC2 = 0x00
The setting that I tried to change to is
ICGC1 = 0x52
ICGC2 = OX03