Freescale S08 controllers have an internal clock generator (ICG) which allows the device to run without an external clock signal. But as devices differ, they need to be calibrated and trimmed. The microcontrollers are usually trimmed in the factory. How can I trim it myself if I need something better?

A good article on trimming can be found in Trimming the Internal Clock Generator on the 68HC908KX8 Microcontroller.

In MCU10.1, the trimming functionality is in the P&E top menu. For MCU10.2, this functionality is now in the debug/run configuration settings. To get there, open the launch/debug configuration (menu Run > Debug Configurations…).

Connection Settings in Run Configuration

Pressing the Edit… button gives me access to the connection settings:

Connection Settings with Advanced Programming Option

The trimming and other advanced options (see Programming part of flash) is behind the ‘Advanced Programming Options’ button:

Trimming in Advanced Options

Note: Looks like trimming is not supported for every S08 device. At least for the MC13213 I do not have the trimming feature in the P&E dialog. But I have it for other devices.

Happy trimming 🙂