MII address register
| GB | MII busy This register field can be read by the application (Read), can be set to 1 by the application with a register write of 1 (Write Set), and is cleared to 0 by the core (Self Clear). The application cannot clear this type of field, and a register write of 0 to this bit has no effect on this field. This bit should read a logic 0 before writing to this register and the MAC_MII_DATA register. This bit must also be set to 0 during a Write to this register. During a PHY register access, this bit will be set to 1 by the Application to indicate that a Read or Write access is in progress. The MAC_MII_DATA register should be kept valid until this bit is cleared by the MAC during a PHY Write operation. The MAC_MII_DATA register is invalid until this bit is cleared by the MAC during a PHY Read operation. This register should not be written to until this bit is cleared. |
| W | MII write When set, this bit tells the PHY that this will be a Write operation using the MII Data register. If this bit is not set, this will be a Read operation, placing the data in the MII Data register. |
| CR | CSR clock range The CSR Clock Range selection determines the frequency of the MDC clock. The suggested range of CLK_M4_ETHERNET frequency applicable for each value below (when Bit[5] = 0) ensures that the MDC clock is approximately between the frequency range 1.0 MHz - 2.5 MHz. When bit 5 is set, you can achieve MDC clock of frequency higher than the IEEE 802.3 specified frequency limit of 2.5 MHz and program a clock divider of lower value. For example, when CLK_M4_ETHERNET is of frequency 100 MHz and you program these bits as 1010, then the resultant MDC clock will be of 12.5 MHz which is outside the limit of IEEE 802.3 specified range. Program the values given below only if the interfacing chips supports faster MDC clocks. See Table 554 for bit values. |
| GR | MII register These bits select the desired MII register in the selected PHY device. |
| PA | Physical layer address This field tells which of the 32 possible PHY devices are being accessed. |
| RESERVED | Reserved |