PRELIMINARY
PM4318 OCTLIU
DATASHEET
PMC- 2001578
ISSUE 3
OCTAL E1/T1/J1 LINE INTERFACE DEVICE
9.15 SBI Extracter and PISO
The SBI Extract block receives data from the SBI ADD BUS and converts it to serial bit streams
for transmission. The SBI Extract block may be configured to enable or disable extraction of
individual tributaries within the SBI ADD bus. It may also be configured to generate an all-1s
output to the transmit LIU when an alarm indication is signalled for a particular tributary via the
SBI bus.
9.16 SBI Inserter and SIPO
The SBI Insert block receives serial data from the LIU octants and inserts it on the SBI DROP
BUS. The SBI Insert block may be configured to enable or disable transmission of individual
tributaries on to the SBI DROP bus.
9.17 SBI to Clk/Data Converter
The OCTLIU may be configured (by setting the SBI_EN and SBI2CLK inputs) to operate in a
mode in which the LIUs are disabled and the device performs conversion between the SBI
interface and serial clock and data (see Figure 6). Up to eight tributaries may be converted to
serial format. The serial data streams are required to share a common clock and frame pulse. In
the egress direction (from SBI ADD BUS to egress clk/data), elastic stores are provided to align
the tributary outputs to a common clock and frame alignment.
9.18 Serial PROM Interface
The serial PROM interface is used to configure the OCTLIU in the absence of a microprocessor.
A single SPI-compatible serial PROM can be used to configure a number of OCTLIU devices
simultaneously (provided all such devices are intended to be configured identically) by connecting
the devices in a cascade as shown in Figure 15.
Figure 15 – Serial PROM Cascade Interface
VCC
SRCASC
SRCASC
VCC
CS
SREN
SRCLK
SRDI
SRCEN
SREN
SRCLK
SRDI
SRCEN
HOLD SCK
SRCCLK
SRCCLK
n.c.
WP
SI
SO
SRDO
SRCDO
SRDO
SRCDO
SPI PROM
OCTLIU -
Cascade Master
OCTLIU -
Cascade Slave
SPI-compatible PROMs are organised as n x 8-bit words. The contents of the PROM are read
sequentially starting at address 0 and continuing until a specially coded stop command is
encountered. Each configuration command is coded in 3-bytes as follows:
PROPRIETARY AND CONFIDENTIAL TO PMC-SIERRA, INC., AND FOR ITS CUSTOMERS’ INTERNAL USE
46
PMC [ PMC-SIERRA, INC ]
