STANDARD PRODUCT
PM4351 COMET
DATA SHEET
PMC-1970624
ISSUE 10
COMBINED E1/T1 TRANSCEIVER
Pin Name
Type
Pin No.
Function
-RI
-NI
G3
RDB
Input
23
24
45
Active Low Read Enable (RDB). RDB is pulsed low to enable a COMET
register read access. The COMET drives the D[7:0] bus with the contents of
the addressed register while RDB and CSB are both low.
WRB
ALE
Input
Input
I/O
J2
Active Low Write Strobe (WRB). WRB is pulsed low to enable a COMET
register write access. The D[7:0] bus contents are clocked into the addressed
normal mode register on the rising edge of WRB while CSB is low.
G9
Address Latch Enable (ALE). This signal latches the address bus contents,
A[8:0], when low, allowing the COMET to be interfaced to a multiplexed
address/data bus. When ALE is high, the address latches are transparent.
D[0]
D[1]
D[2]
D[3]
D[4]
D[5]
D[6]
D[7]
A[0]
A[1]
A[2]
A[3]
A[4]
A[5]
A[6]
A[7]
A[8]
RSTB
26
27
28
29
32
33
34
35
36
37
38
39
40
41
42
43
44
22
H3
J4
Bi-directional Data Bus (D[7:0]). This bus is used during read and write
accesses to internal COMET registers.
H4
F4
G5
F5
H6
J7
Input
J6
Address bus (A[8:0]). This bus selects specific registers during COMET
register accesses.
H5
H7
J8
G6
J9
H8
G7
H9
H2
Input
Active Low Reset (RSTB). When forced low, RSTB will asynchronously reset
the COMET. RSTB is a Schmitt-trigger input with integral pull-up. When
resetting the device, RSTB must be asserted for a minimum of 100 ns to
ensure that the COMET is completely reset.
INTB
OD
25
J3
Active Low Open-drain Interrupt (INTB). INTB drives low when an unmasked
interrupt event is detected on any of the internal interrupt sources. Note that
INTB will remain low until all active, unmasked interrupt sources are
acknowledged at their source at which time, INTB will tristate.
Output
PROPRIETARY AND CONFIDENTIAL
27
PMC [ PMC-SIERRA, INC ]
