STANDARD PRODUCT
PM4351 COMET
DATA SHEET
PMC-1970624
ISSUE 10
COMBINED E1/T1 TRANSCEIVER
Pin Name
Type
Pin No.
Function
-RI
-NI
TVREF
RVREF
Analog
I/O
76
A4
Transmit Voltage Reference (TVREF). This pin is reserved for a precision
analog voltage or current reference.
Analog
I/O
60
D7
C8
Receive Voltage Reference (RVREF). This pin is reserved for a precision
analog voltage or current reference. This pin must be connected to an external
RC network consisting of a 100 kohm resistor connected in parallel with a
10 nF capacitor to analog ground.
TRIMF
Input
58
Trim Fuse. This pin is reserved for production purposes. The TRIMF signal is
used during COMET production test to control the trimming of fuses. This pin
must be tied low for normal operation.
Table 7
- JTAG (IEEE 1149.1) Boundary Scan Test Interface (5 pins)
Pin Name
Type
Pin No.
Function
-RI
-NI
TCK
TMS
Input
Input
16
F1
Test Clock (TCK). The test clock (TCK) signal provides timing for test
operations that are carried out using the IEEE P1149.1 test access port.
17
E2
G2
H1
Test Mode Select (TMS). The test mode select (TMS) signal controls the test
operations that are carried out using the IEEE P1149.1 test access port. TMS
is sampled on the rising edge of TCK. TMS has an integral pull-up resistor.
TDI
Input
18
19
Test Data Input (TDI). The test data input (TDI) signal carries test data into the
COMET via the IEEE P1149.1 test access port. TDI is sampled on the rising
edge of TCK. TDI has an integral pull-up resistor.
TDO
Output
with
Test Data Output (TDO). The test data output (TDO) signal carries test data
out of the COMET via the IEEE P1149.1 test access port. TDO is updated on
the falling edge of TCK. TDO is a tristate output which is tristated except when
scanning of data is in progress.
Tristate
TRSTB
Input
20
F3
Active Low Test Reset (TRSTB). The test reset (TRSTB) signal provides an
asynchronous COMET test access port reset via the IEEE P1149.1 test access
port. TRSTB is a Schmitt triggered input with an integral pull-up resistor.
The JTAG TAP controller must be initialized when the COMET is powered up.
If the JTAG port is not used, TRSTB should be connected to the RSTB input.
Table 8
- Microprocessor Interface (23 pins)
Pin Name
Type
Pin No.
Function
-RI
21
-NI
CSB
Input
J1
Active Low Chip Select (CSB). CSB must be low to enable COMET register
accesses. CSB must go high at least once after power up to clear internal test
modes. If CSB is not used, it should be tied to an inverted version of RSTB, in
which case, RDB and WRB determine register accesses.
PROPRIETARY AND CONFIDENTIAL
26
PMC [ PMC-SIERRA, INC ]
