RM0082
HS_Media independent interface (MII)
Doc ID 018672 Rev 1
541/844
●
GW
If this bit is set, the PHY is informed that the current operation will be a Write operation
using the MII Data register. Otherwise (bit cleared), this will be a Read operation
placing the data in the MII Data register.
●
GB
This bit should read a logic 1'b0 before writing to this register (Register4, MII Address)
and Register5 (MII Data, section 1.4.2.19). During a PHY register access, this bit will
be set to 1'b1 by the application to indicate that a Read or Write access is in progress.
This bit must be set to 1'b0 during a Write to this Register4. This Register4 should not
be written to until this bit is cleared.
Register5 should be kept valid until this bit GB is cleared by the MAC during a PHY
Write operation. Besides, the same Register5 is invalid until this bit is cleared by the
MAC during a PHY Read operation.
24.7.21
MII data register (Register5, MAC)
The MII data is a register which stores the 16 bit write data to be written to the PHY register
located at the address indicated in MII address register (
). It also stores the
16 bit read data from the PHY register located at the same address. The MII data bit
assignments are given in
.
24.7.22
Flow control register (Register6, MAC)
The Flow Control is a register which controls the generation and reception of the Control
(pause command) frames by the MAC. The flow control bit assignments are given in
Table 449.
CR field bit assignments
Value
CSR Frequency Range
MDC Clock
3‘b000
60-100 MHz
CSR clock/42
3‘b001
100-150 MHz
CSR clock/62
3‘b010
20-35 MHz
CSR clock/16
3‘b011
35-60 MHz
CSR clock/26
3‘b100
150-250 MHz
CSR clock/102
3‘b101
250-300 MHz
CSR clock/122
3‘b110
Reserved
-
3‘b111
Reserved
-
Table 450.
MII data register bit assignments
Bit
Name
Reset value Type
Description
[31:16]
Reserved
-
RO
Read: undefined.
[15:00]
GD
16’h0
RW
MII data.