PRELIMINARY
PM4318 OCTLIU
DATASHEET
PMC- 2001578
ISSUE 3
OCTAL E1/T1/J1 LINE INTERFACE DEVICE
Pin Name
Type
Pin
No.
Function
INTB/LEN6[0]
Open-
drain
Output
D17
Active low Open-Drain Interrupt (INTB). This signal goes 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.
INTB shares the same pin as the LEN6[0] input. INTB is selected
when HW_ONLY is tied low.
D[0]/LEN6[1]
D[1]/LEN6[2]
D[2]/LEN7[0]
D[3]/LEN7[1]
D[4]/LEN7[2]
D[5]/LEN8[0]
D[6]/LEN8[1]
D[7]/LEN8[2]
I/O
B19
A20
A19
B18
A18
D15
B17
C15
Bidirectional Data Bus (D[7:0]). This bus provides OCTLIU
register read and write accesses.
D[7:0] share the same pins as some of the LENx[2:0] inputs.
D[7:0] are selected when HW_ONLY is tied low.
Hardware-Only Control Interface
HW_ONLY
Input
B1
The Hardware Only mode enable signal (HW_ONLY) selects
between the microprocessor-controlled and hardware-only modes
of operation. When HW_ONLY is tied low, the microprocessor
interface is enabled. When HW_ONLY is tied high, the hardware-
only control interface is enabled and the microprocessor interface
is unused.
SRCASC
Input
B3
Serial PROM Cascade Control (SRCASC). When SRCASC is
tied low, the OCTLIU acts as the Serial PROM master controller
and the SREN, SRCLK, SRDI and SRDO pins should be
connected to the serial PROM. When SRCASC is tied high, the
OCTLIU acts as a Serial PROM cascade slave and the SREN,
SRCLK and SRDO pins should be connected to the SRCEN,
SRCCLK and SRCDO pins of another OCTLIU device upstream
in the cascade.
SREN
I/O
C4
Serial PROM Enable (SREN). When operating as a Serial PROM
master (SRCASC tied low), the SREN pin functions as an output
and generates an active low chip select signal for the serial
PROM. When operating as a Serial PROM slave (SRCASC tied
high), the SREN pin functions as an input and indicates the
validity of cascade data on the SRDO input.
When configured as an output, SREN is updated on the falling
edge of SRCLK. When configured as an input, SREN is sampled
on the rising edge of SRCLK.
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS’ INTERNAL USE
25
PMC [ PMC-SIERRA, INC ]
