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CR bit
HCLK clock
MDC clock
011
35-60MHz
AHB clock/26
100
150-180MHz
AHB clock/102
101
、
110
、
111
Reserved
-
SMI write operation
When MB bit and MW bit of MAC_ADDR are set to 1 by application program,
SMI will trigger write operation of PHY register by transmitting PHY address,
and register address in PHY, and writing data. When performing write operation,
the application program cannot modify MAC_ADDR and MAC_DATA registers.
After write operation is completed, SMI will reset MB bit.
SMI read operation
When MB bit of MAC_ADDR is set and MW bit is cleared to zero, SMI will
trigger read operation of PHY register by transmitting PHY address, and register
address in PHY. When performing read operation, the application program
cannot modify MAC_ADDR and MAC_DATA registers. After read operation is
completed, SMI will reset MB bit, and update the read data from PHY to
MAC_DATA register.
Media independent interface (MII)
MII defines the interconnection between MAC sublayer and PHY at data
transmission rate of 10 Mbit/s and 100 Mbit/s.
The signals are as follows:
MII_TX_EN: Transmit enable signal; MAC is currently transmitting half
byte for MII
MII_RX_DV: Data receiving effective signal; PHY is currently receiving
recovered and decoded half byte of MII
MII_TXD [3:0]: Data transmitting signal
MII_RXD [3:0]: Data receiving signal
MII_RX_ER: Receiving error signal
MII_TX_CLK: Continuous clock signal, providing reference timing for TX
data transmission
MII_RX_CLK: Continuous clock signal, providing reference timing for RX
data transmission
MII_CRS: Carrier sense signal
MII_COL: Conflict detection signal