DESCRIPTION AND OPERATION
SLAVE EXPANDER BUS INTERFACE
I-E96-315B
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SLAVE EXPANDER BUS INTERFACE
The slave expander bus interface enables communication
between the processor module and the HSS. This communica-
tion channel is a an eight bit parallel data bus with two control
lines. A Bailey Controls designed integrated circuit performs
the communications protocol for interfacing the data and sta-
tus information to the processor module. It performs address
compare, R/W strobe generation and contains bus drivers and
receivers.
The user selects the slave expander bus address by setting a
dipswitch on the HSS. The address byte precedes every data
transfer. The slave expander bus integrated circuit does an
address comparison before allowing data to transfer on the
slave expander bus. If the addresses match, the MFP can
strobe data to or from the slave expander bus.
The MFP sends the following information and commands to the
HSS by way of the slave expander bus interface:
Position demand
Calibrate/operate mode select
Calibrate go/hold status
Calibration stroke time
Number of calibration cycles
Null check request
The HSS sends the following information and status to the
MFP by way of the slave expander bus interface:
Actuator position
Actuator at LVDT null
New calibration data
Slave, mode = normal/emergency manual
Calibration status
Good/bad status for:
Positioning
A/D and D/A
Oscillator
LVDT secondaries
Output 1
Output 2
Microprocessor/hardware
Communications
