PMC-Sierra, Inc.
PRELIMINARY
PM5381 S/UNI-2488
DATASHEET
PMC-2000489
ISSUE 1
SATURN USER NETWORK INTERFACE FOR 2488 MBIT/S
10.21.3 LVDS Transmit Reference (TXREF)
The TXLVREF provides an on-chip bandgap voltage reference (1.20V ±5%) and a precision
current to the TXLVs. The reference voltage is used to control the common-mode level of the
TXLV output, while the reference current is used to control the output amplitude. The precision
currents are generated by forcing the reference voltage across an external, off-chip 4.75kΩ (±1%)
resistor. The resulting current is then mirrored through several individual reference current
outputs, so each TXLV receives its own reference current.
10.21.4 Clock Synthesis Unit (CSU)
The CSU is a fully integrated clock synthesis unit. It generates low jitter multi-phase differential
clocks at 777.6 MHz for the usage by the transmitter.
10.22 JTAG Test Access Port Interface
The JTAG Test Access Port block provides JTAG support for boundary scan. The standard JTAG
EXTEST, SAMPLE, BYPASS, IDCODE and STCTEST instructions are supported. The
S/UNI-2488 identification code is 053810CD hexadecimal.
10.23 Microprocessor Interface
The Microprocessor Interface Block provides the logic required to interface the generic
microprocessor bus with the normal mode and test mode registers within the S/UNI-2488. The
normal mode registers are used during normal operation to configure and monitor the
S/UNI-2488. The test mode registers are used to enhance the testability of the S/UNI-2488. The
register set is accessed as shown below. The corresponding memory map address is identified
by the address column of the table. Addresses that are not shown are not used and must be
treated as Reserved.
Table 7: Register Memory Map
Address
Register Description
S/UNI-2488 Identity, and Global Performance Monitor Update
S/UNI-2488 Master Reset, Configuration, and Loopback
S/UNI-2488 Reserved
0000
0001
0002
0003
0004
0005
0006
0007
0008
0009
000A
000B
S/UNI-2488 Clock Monitors
S/UNI-2488 Master Interrupt Status #1
S/UNI-2488 Master Interrupt Status #2
S/UNI-2488 Master Interrupt Status #3
S/UNI-2488 Master Interrupt Status #4
S/UNI-2488 Master Interrupt Status #5
S/UNI-2488 Master Interrupt Status #6
S/UNI-2488 Master Interrupt Status #8
Unused
Proprietary and Confidentail to PMC-Sierra Inc., and for its Customer’s Internal Use
83
PMC [ PMC-SIERRA, INC ]
