LS1043A 中EMI1_MDC/MDIO接口时序问题:
根据手册147页的示意图,写时序:EMI1在MDC上升沿延迟tMDKHDX后数据翻转,但是示波器实际测量MDC是在下降沿打出数据,如下图:这是手册描述问题还是有什么配置呢?
另外,读时序时:PHY在MDC的上升沿经过一段延迟后扇出数据,CPU也是利用这个上升沿采样吗?还是可以配置CPU使用下降沿采样?
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Please refer to the QorIQ LS1043A Data Path Acceleration Architecture (DPAA) Reference Manual.
MDIO behaviour in the provided trace is valid.
Please check MDC to MDIO delay tMDKHDX controlled by the MDIO_CFG[MDIO_HOLD].
Please check whether MDIO_CFG[NEG]=1 then LS1043A will transmit data on falling edge of the clock.
This implies with MDIO_CFG[NEG]=1 the tMDKHDX should be measured with respect to the falling edge of clock.
> can I configure the CPU to use falling edge sampling?
No.
where could I find these registers in the doc: QorIQ LS1043A Reference Manual Rev. 4, 6/2018.
Thanks.
Please refer to the QorIQ LS1043A Data Path Acceleration Architecture (DPAA) Reference Manual.