RS08LA8 use of ICSIRCLK

[gosa]

Hi

I'm new in freescale microcontrollers and I start with RS08LA. I check and test what clocksource I have for system, timer, etc and I woundering that I can not found supported ICSIRCLK from internal clock source (ICS) for system clock distribution (figure 1-2 in datasheet). So what is the use of ICSIRCLK?

KR

[Monica]

Hello KR

I found this paragraph in the Data Sheet that might reply to your question:

10.4.5 Internal Reference Clock

When IRCLKEN is set the internal reference clock signal will be presented as ICSIRCLK, which can be used as an additional clock source. The ICSIRCLK frequency can be re-targeted by trimming the period of the internal reference lock. This can be done by writing a new value to the TRIM bits in the ICSTRM register. Writing a larger value will slow down the ICSIRCLK frequency, and writing a smaller value to the ICSTRM register will speed up the ICSIRCLK frequency. The TRIM bits will effect the ICSOUT frequency if the ICS is in FLL engaged internal (FEI), FLL bypassed internal (FBI), or FLL bypassed internal low power (FBILP) mode. The TRIM and FTRIM value will not be affected by a reset.

Let me know if it does address your question, I will be around!

Regards.

[gosa]

Hi Monica

Your link of data sheet reference to S08SH8 but I use the RS08LA8. In the RS08LA8 I can not found any usage of ICSIRCLK. It will be distributed in the Internal Clock Source ICS (figure 9-2) but does not appear in the clock connection diagramm (figure 1-2). I just wondering about that issue.

Regards

[bigmac · Accepted solution]

Hello KR,

The ICS module is present in many MCU derivatives, from both S08 and RS08 families.  I guess the answer to your query is that the ICSIRCLK signal is present within the module itself, but is never used for the RS08 device that you are using.  It would seem an unfortunate omission if this is not clarified in the introductory paragraphs of the ICS chapter within the specific datasheet.

Regards,

Mac