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xjtuecho / EBAZ4205

A 5$ Xilinx ZYNQ development board.
MIT License
627 stars 164 forks source link

Frequency info #7

Closed doppioandante closed 3 years ago

doppioandante commented 3 years ago

If I can correctly interpret the pics, the external crystal is at 25MHz, is this correct? Does the FPGA run at this frequency?

tpecar commented 3 years ago

The 25MHz crystal (Y3) is for the ethernet phy.

Zynq uses the 33.333MHz crystal (X8), which can then be internally multiplied by a PLL - this depends on your design, the firmware already present on the flash chip seems to use 666.66 MHz for the ARM core (judging from the BogoMIPS).

The overview datasheet specifies max frequency 667MHz for grade 1 Z-7010 used on these boards. But again, the actual frequency you can use will be determined by your design.

doppioandante commented 3 years ago

Thank you, that's exactly what I needed to know