The flyleaf page of the MC9S08SH8 data book says that with the internal clock source the MPU should "support bus frequencies from 2 MHz to 20 MHz". When I tried setting the ICSTRM to get 20 or 16 MHz the chip failed. No problem setting to 8 MHz. When I tried to load a simple test program into the chip at a 12 MHz it seemed to work. At 8 MHz the ICSTRM value for this particular chip was $BC and to get 12 MHz the value need was $3E.
The little test program sends out a message at 9600 baud and blinks a LED works at 12 MHz but now I can no longer communicate with the chip with my OSBDM. Does anyone have any idea why that may be?
Has anyone got the faster bus frequencies with the SH8?