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LPC54608 Ethernet MDIO CSR clock range for 180MHz

Question asked by hlsamts on Aug 28, 2017
Latest reply on Aug 31, 2017 by jeremyzhou

I am using the LPC54608 evaluation board OM13092 and want to get Ethernet running using a system core clock of 180 MHz. The examples of the SDK2.2 use only 48 MHz system core clock.

 

In the MAC_MDIO_ADDR register I have to select a CSR clock range (Bits 11:8). According to the user manual Rev2.0, I can set CSR values for clock ranges up to 150 MHz. How can I set a clock range for 180 MHz?

 

Best regards,

Holger

 

Source: UM10912 User Manual Rev. 2.0

(Source: NXP UM10912 User Manual Rev. 2.0, Table 800)

 

P.S. The OM13092 uses a LAN8720 phy, which allows for a maximum MDC clock period of 400ns -> 2.5 MHz. If I would use the register value 1, I would get a clock of 180MHz / 62 = 2.9 MHz. Therefore I need the possibility to get a lower MDIO clock.

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