IP2022 User’s Manual—Peripherals www.ubicom.com 267 implementation of protocol conversion or bridging functions, such
as a USB to 10Base-T Ethernet bridge. Each SERDES unit uses up to 8 digital signals: SxCLK, SxRXD,
SxRXM, SxRXP, SxTXM, SxTXME, SxTXP, and SxTXPE/SxOE.
The signals for SERDES1 are multiplexed with the Port E pins,
and the signals for SERDES2 are multiplexed with the Port F pins.
The port direction bits must be set appropriately for each pin that
is used. The SxOE signal is multiplexed with the SxTXPE signal.
Port pin usage is shown in Table 4-4. Not all signals are used in all
protocol modes (see Table 4-7 for details). Table 4-4  SERDES Digital Port Pin Usage SERDES1 Signal Port Pin SERDES2 Signal Port Pin Description S1CLK RE0 S2CLK RF0 Serial clock S1RXP RE1 S2RXP RF1 Plus-side differential input S1RXM RE2 S2RXM RF2 Minus-side differential input S1RXD RE3 S2RXD RF3 Serial data S1TXPE S1OE RE4 S2TXPE S1OE RF4 Plus-side differential output with
pre-emphasis, or output enable
for external transceiver S1TXP RE5 S2TXP RF5 Plus-side differential output S1TXM RE6 S2TXM RF6 Minus-side differential output S1TXME RE7 S2TXME RF7 Minus-side differential output
with pre-emphasis