XRT91L34IV-F View Datasheet(PDF) - Exar Corporation
Part Name
Description
MFG CO.
'XRT91L34IV-F' PDF : 38 Pages View PDF
REV. 1.0.1
XRT91L34
QUAD CHANNEL MULTIRATE STS-12/3/1 AND STM-4/1/0 SONET/SDH CDR
SERIAL MICROPROCESSOR INTERFACE
NAME
HOST/HW
LEVEL
LVTTL,
LVCMOS
TYPE
I
CS
LVTTL,
I
LVCMOS
SCLK
LVTTL,
I
LVCMOS
DLOSDIS
LVTTL,
I
/SDI
LVCMOS
PIN
DESCRIPTION
122 Host or Hardware Mode Select Input
The XRT91L34 offers two modes of operation for interfacing to the
device. The Host mode uses a serial microprocessor interface for
programming individual registers. The Hardware mode is controlled
by the state of the hardware pins set by the user. When left uncon-
nected, by default, the device is configured in the Hardware mode.
"Low" = Hardware Mode
"High" = Host Mode
This pin is provided with an internal pull-down.
38 Chip Select Input (Host Mode)
Active "Low" signal. This signal enables the serial microprocessor
interface by pulling chip select "Low". The serial microprocessor is
disabled when the chip select signal returns "High".
NOTES:
1. The serial microprocessor interface does not support burst
mode. Chip Select must be de-asserted after each
operation cycle.
2. Chip Select is only active in Host Mode.
This pin is provided with an internal pull-up.
37 Serial Clock Input (Host Mode Only)
Once CS is pulled "Low", the serial microprocessor interface
requires 16 clock cycles for a complete Read or Write operation.
Serial Clock Input is only active in Host Mode.
This pin is provided with an internal pull-down.
39 Serial Data Input (Host Mode Only)
When CS is pulled "Low", the serial data input is sampled on the ris-
ing edge of SCLK.
Serial Data Input is only active in Host Mode.
This pin is provided with an internal pull-down.
SDO
INT
LVCMOS
O
LVCMOS
O
Hardware Mode This pin is functions as the DLOSDIS control pin.
40 Serial Data Output (Host Mode Only)
If a Read function is initiated, the serial data output is updated on
the falling edge of SCLK8 through SCLK15, with the LSB (D0)
updated first. This enables the data to be sampled on the rising
edge of SCLK9 through SCLK16.
Serial Data Output is only active in Host Mode.
41 Interrupt Output (Host Mode Only)
Active "Low" signal. This signal is asserted "Low" when a change in
alarm status occurs. Once the status registers have been read, the
interrupt pin will return "High".
Interrupt Output is only active in Host Mode.
NOTE: This open-drain output pin requires an external pull-up
resistor.
11
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