Hello,

I am working with the SAM7A3 but being new to this something isn't clear. The datasheets point out that the maximum crystal frequency to be used is 20MHz, and that the maximum external clock frequency is 50MHz. However, the controller is rated up to 60MHz on the Atmel site. How is this possible?

Also, I am not too clear on the effect of the PLL block. Besides increasing the accuracy of the utilized clock signal, is it possible to multiple the frequency of the external crystal/clock? IE, Having a 20MHz crystal and somehow multiplying the frequency so as to run the processor at 60MHz?

Again, I am new, so minimize the flaming... Thank you.

Hi,
yes the PLL can be used to multiply the input frequency. This is done in the most cases. So you can reach 60 MHz with a 20 MHz crystal.

Take a look into the data sheet of the processor.

Best regards,
Edi

Thank you, about to dive into the datasheet.