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IXF1104 4-Port Gigabit Ethernet Media Access Controller
97 Datasheet
Document Number: 278757
Revision Number: 009
Revision Date: 27-Oct-2005
5.4.2 Timing Specifics
The IXF1104 MAC RGMII complies with RGMII Rev1.2a requirements. Table 27 provides the
timing specifics.
5.4.3 TX_ER and RX_ER Coding
To reduce interface power, the transmit error condition (TX_ER) and the receive error condition
(RX_ER) are encoded on the RGMII interface to minimize transitions during normal network
operation (refer to Table 28 on page 97 for the encoding method). Table 27 provides signal
definitions for RGMII.
The value of RGMII_TX_ER and RGMII_TX_EN are valid at the rising edge of the clock while
TX_ER is presented on the falling edge of the clock. RX_ER coding behaves in the same way (see
Table 28, Figure 19, and Figure 20).
Table 27. RGMII Signal Definitions
IXF1104
MAC Signal
RGMII
Standard
Signal
Source Description
TXC_0:3 TXC MAC
Depending on speed, the transmit reference clock is 125 MHz, 25
MHz, or 2.5 MHz +/– 50ppm.
TD[3:0]_n TD<3:0> MAC
Contains register bits 3:0 on the rising edge of TXC and register bits
7:4 on the falling edge of TXC.
TX_EN TX_CTL MAC
TXEN is on the leading edge of TXC.
TX_EN xor TX_ER is on the falling edge of TXC.
RXC_0:3 RXC PHY
Continuous reference clock is 125 MHz, 25 MHz, or 2.5 MHz +/– 50
ppm.
RD[3:0]_n RD<3:0> PHY
Contains register bits 3:0 on the leading edge of RXC and register bits
7:4 on the trailing edge of RXC.
RX_DV RX_CTL PHY
RX_DV is on the leading edge of RXC.
RX_DV or RXERR is the falling edge of RXC.
Table 28. TX_ER and RX_ER Coding Description
Condition Description
Receiving valid frame,
no errors
RX_DV = true
Logic High on rising edge of RXC
RX_ER = false
Logic High on the falling edge of RXC
Receiving valid frame,
with errors
RX_DV = true
Logic High on rising edge of RXC
RX_ER = true
Logic Low on the falling edge of RXC
Receiving invalid frame
(or no frame)
RX_DV = false
Logic Low on rising edge of RXC
RX_ER = false
Logic Low on the falling edge of RXC
Transmitting valid frame,
no errors
TX_EN = true
Logic High on rising edge of TXC
TX_ER =false
Logic High on the falling edge of TXC
Transmitting valid frame
with errors
TX_EN = true
Logic High on rising edge of TXC
TX_ER = true
Logic Low on the falling edge of TXC
Transmitting invalid
frame (or no frame)
TX_EN = false
Logic Low on rising edge of TXC
TX_ER = false
Logic low on the falling edge of TXC
NOTE: Refer to Figure 19 for TX_CTL behavior, and Figure 20 for RX_CTL behavior.