User Manual Part 1

CIRCUIT ANALYSIS
38 MM101271V1 R2A
Access to various board inputs/outputs is made available through Electronically
Programmable Logic Device (EPLD) U27. The EPLD contains numerous read/write
latches with a simple 8-bit interface to the microprocessor.
The EPLD is in-circuit programmable via the JTAG port using an Altera Byte-blaster
cable. A 10-Pin header J10 is made available for this purpose. The EPLD JTAG port is
also brought to microprocessor I/O pins to allow the microprocessor to load the EPLD
configuration.
The JTAG port is routed to Modem board (A2-A1). This allows a future modem board to
be designed with an Altera EPLD. If that future EPLD modem board is used, resistor
R187 (0 ohms) must be removed from the board.
In addition to being an interface to the discrete I/O, the EPLD also divides clocks and
provides the output enable logic for the 8-bit data bus transceiver. It also derives the FSL
pulse stream from RFTXDAT and RFTXCLK in the Control Channel mode.
7.3.7 Ethernet Ports
There are two Ethernet Port circuits for the Controller Board shown on Schematic
Diagram WD-CB101069V1, Sheets 12 & 13 as:
• 10 Base-T (10 Mbit PHY) • 10/100 Base-T (10/100 Mbit PHY)
The 10/100 Mbit port (10/100 Base-T Transceiver U5) uses the Fast Ethernet Controller
(FEC) inside the microprocessor and supports full duplex (10/100 Base-T). The 10 Mbit
port (10 Base-T Transceiver U12) uses SCC1 and only supports half-duplex (10 Base-T).
The ethernet physical layer transceivers are the same for both ports, but the 10/100 Mbit
port uses a Media Independent Interface (MII), whereas the 10 Mbit uses a
“7-wire”
interface. The ethernet transceivers support 10/100 Base-T with full auto-negotiation
capability, while the 10 Mbit port only advertises 10 Mbit capability.
The RJ-45 ethernet connectors are actually located on Interconnect Board A1. The
ethernet physical layer chips and transformers reside on the Controller Board with the
ethernet differential RX/TX signals brought to the RJ-45 connectors through the
Interconnect Board connector. A single LINK OK status LED is provided for each
ethernet port on the front of the Controller Board.
The 10Mbit Ethernet port uses the
“7-wire”
interface to connect the Ethernet physical
transceiver to the microprocessor SCC1 serial channel. When SCC1 is in Ethernet mode,
the SCC pins have different functions (refer to the following table).
Table 6 - 10 Mbit Ethernet Connections
SCC ETHERNET SIGNAL SCC PIN NAME PHY SIGNAL
TX TXD1 10TXD
TENA RTS1 10TXEN
TCLK CLKx 10TXCLK
CLSN CTS1 10COL
RENA CD1 10CRS
RX RXD1 10RXD
TCLK CLKx 10RXCLK