Sensoray 425 - Manual (Page 6)

Sensoray Model 425 Instruction Manual Page 4
Reset
The 425 may be reset by either “hard reset” from the ISAbus
system reset signal or “soft reset” under software control of
the ISAbus master. A reset may be performed at any time.
Soft Reset
A “soft reset” causes a local reset on only the 425 board and
will not reset any other devices on the ISAbus. A soft reset is
invoked by writing to the Reset port at the board base
address + 62.
The value written to the Reset port should be all zeros to
ensure compatibility with future product enhancements.
Board State During Reset
The board’s fault indicator will activate upon receipt of a soft
or hard reset command. The indicator will remain active
until the reset command is released and the board completes
an initialization sequence. During this initialization
sequence, the board exhibits the following behavior:
• Only the Status and Reset ports are accessible.
• The Status port FLT flag is valid; all other Status port flags
are meaningless.
Default State Following a Reset
When the initialization sequence is completed, the fault
indicator will turn off, all board I/O ports become accessible
and the board defaults to the following condition:
• Watchdog Timer
Disabled
Fast mode (630 milliseconds)
• D/A Converters
Outputs are disabled
Setpoints are indeterminate
• Encoder Counters
Reset to zero counts
Forced to Mode 0
Event captures disabled
Index capture type selected
• Relay Channels
Switched to off (open-collector, pulled up) state
Event captures disabled
Negative edge capture is selected
• A/D Converter
Forced to unipolar mode
Input channel 0 selected
• Interrupts
Board master interrupt enabled
Encoder counter interrupts disabled
Relay interrupts disabled
Reset port (base + 62, write only):
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Fault Indicator
A red light-emitting diode located near the top edge of the
circuit board indicates reset and fault conditions. In normal
operation, the indicator emits only during system or local
(board) reset. The indicator should be off at all other times.
When the indicator is emitting, the board is said to be in a
“fault” condition, regardless of whether a true fault condition
exists or the board is simply being reset.
Functional Limitations During Fault
While the fault indicator is active, only the Status and Reset
ports are available to the ISAbus master. Consequently, the
host should limit itself to accessing these two ports during a
fault condition.
The state of the fault indicator may be read by the host
processor through the status port.
Persistent Fault
If the fault indicator remains on for more than one-half
second following a reset, a genuine fault condition may exist
on the board that requires servicing.
Before servicing the unit, make sure that your ISAbus master
is not invoking repeated soft resets. Also, verify that there
are no addressing conflicts between 425 and system board or
other expansion boards in your system.
Status Register
A status port, located at board base address + 22, makes
available status bits to the ISAbus host. Unless otherwise
specified, all status bits are active high.
FLT — reflects state of the Fault LED. *
CP2 — counter 2 event captured
CP1 — counter 1 event captured
CP0 — counter 0 event captured
RQR — relay interrupt service request.
RQ2 — counter 2 interrupt service request.
RQ1 — counter 1 interrupt service request.
RQ0 — counter 0 interrupt service request.
IE# — board master interrupt enabled (active low).
WDI — watchdog slow timeout interval.
WDR — watchdog timer timed out.
BSY — ADC is busy digitizing.
AE — DAC outputs are enabled.
WDE — watchdog timer is enabled.
BIP — ADC is programmed for unipolar operation.
* After a reset, verify that FLT is false before attempting to
access other registers on the board. Only the Status and Reset
ports are functional while FLT is active.
Status port (base + 22, read only):
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
FLT CP2 CP1 CP0 RQR RQ2 RQ1 RQ0 x IE# WDI WDR BSY AE WDE BIP