Rack Interface Card; Specifications; Baud Rate - HP M2350A Service Manual

Understanding the Computer Module
The Function Cards
bit 1 (databit9) This is used to reset the SIC Chip. Sometimes it is necessary to reset the SIC
Chip and not the whole system.
bit 2
(databitlo)
This is used to disable the Multiplexer before control of the SIC-RAM is passed
between the UTIL-CPU and the SIC Chip and then enable it after the switch.
This suppresses spikes and protects the contents of the SIC-RAM.
bit 3
(databit1 1)
This is used to switch on the error'LED while tests are performed on the SDN
interface card. When all tests are successfully completed the error LED is
switched off.
n
Translates MPB parallel data broadcast on an 8-bit bus to serial SDN data broadcast on a
2-wire bus.
H Receives all SDN messages, alarms and data (parameters and waves).
H Synchronizes the system frame interrupt with the SDN poll cycle (performed by the
UTILXPU card.)
n
Detects primary bedside unit mode, either SDN or "Auto-poll" and terminates the line as
necessary.
n
Controls transmit data from primary bed unit and another instrument for example, a local
recorder using a priority wire.
n
Data can be selectively acquired, with no CPU intervention by placing "tune" headers in the
SIGN-RAM of the SIC Chip.
4 Incoming data synchronized using 28.8MBz oscillator.
n
SIC-RAM consists of two 2kB buffers (1 transmit, 1 receive).
w Latch controls, error LED, SIC-Chip reset, multiplexer switch and multiplexer disable/enable.
Rack Interface Card
The Rack Interface card supports the frontend link protocol (frontend mode) for
communication between the system, via the Utility CPU, and the integral rack housing up to
two recorder modules. The function of the card is to acquire data and status from the recorder
modules in the rack and send control signals to
the
modules, using the Front End high-speed
serial link (FE-LINK).
Note
No RS232 protocol is provided by this card: Any communication with RS232
1
devices is routed via a level converter.
Specifications
Baud Rate.
Transmit and receive channels both operate at the following baud rates:
Frontend mode: 500000 Bd
Tool Mode:
9600
Bd
-422 Drive.
OFF/ON = as recommended with RS422 standard, OV to 5V differential. No
termination.
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