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Altera_Forum
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19 years ago

50Mhz to 60Mhz

Dear everyone! I desig a nios2 system with EPC2C5Q208C8 ,DM9000A, running uClinux, when I test at 50Mhz, everything is OK, but when I chanhe it to 60 Mhz, the ethernet can'...
Altera_Forum's avatar
Altera_Forum
Icon for Honored Contributor rankHonored Contributor
19 years ago

the dm9000a only works with 25 MHz, if you cant generate this clock with a FPGA PLL tthen you must provide a 25 MHz cristal.

On the De2 board the clock for the dm9000a is derived from the 50 MHz system clock.

See the de2 brd verilog file.

reg ENET_CLK;

always@(posedge OSC_50) ENET_CLK=~ENET_CLK;