GP32 Questions Re. Clocks

[velvetfr]

Hi,

I am currently designing some functions to set the clock registers of the GP32. When reading the Samsung Arm920T manual, I see that there is a limit for HCLK and PCLK of 66MHz, which in fact limit also FCLK (due to the fact that FCLK is used as a master clock for HCLK and PCLK) to 132MHz ... what is about this 166MHz overclocking, and I assume that this trick do not respect this limit of 66MHz for HCLK and PCLK ? Am I right, or miss something ?

Thanks,
velvetfr

 

[Robster]

You are right.

To run the CPU at 166MHz, you set FCLK (also known as MCLK) to 166MHz, and the H-divider is 2, so HCLK is 83MHz. This is outside the specified range, which is why it's called overclocking

Note that you can also set the PCLK divider (from HCLK) to 1 or 2, so at 166MHz PCLK can be 83MHz or 41MHz. Most programs that I've seen set it to 83MHz.