Dependency between S08RN's ICS_C3 register and the internal trimmed oscillator

[cristianstancu]

Hello,

What is the direct dependency between the ICS_C3 value from the register and the internal trimmed oscillator ?

How much is the frequency decreased with 1 increment in that register (best case and worst case) ?

I searched through application notes and the datasheet for S08RN microcontrollers and I couldn't find a specific value.

I need this figure in order to be able to calculate that I can reach a certain accuracy with the system oscillator.

Thanks in advance.

[vicentegomez]

Hi Cristian

I check it using PE on the S08PT ( I do not have the S08RN) and with 0x81 on ICS_C3  I got 31.25  KHz also you need to check the ICS_C4 due the fine trim is on that register. for this case ICS_C4 was 0

But while I was testing different value on the ICS_C3 I saw that this is no lineal, so I can not give you an spec for that.

Some data that I got was 39 KHz ICS_C3 = 0x43 ICS_C4 = 0

39 KHz ICS_C3 = 0x43 ICS_C4 = 0

31.50 KhZ  ICS_C3 = 0x7E ICS_C4 = 0x00

31.45 KhZ  ICS_C3 = 0x7E ICS_C4 = 0x01

Note I also was using the ciclone pro to debug the board.

Regards

Vicente Gomez