Sensoray 421 - Manual (Page 19)

Sensoray Model 421 Instruction Manual Page 17
Appendix B: I/O Map Summary
Adrs Write Function Read Function
0 DAC0LSB
Loads DAC 0 LSB register without updating the DAC output.
LDAC
Transfers all DACxMSB and DACxLSB data to the DAC output
registers, updating all DAC outputs simultaneously. The returned
data value is random and has no significant meaning.
1 DAC0MSB
Loads DAC 0 MSB register without updating the DAC output.
2 DAC1LSB
Loads DAC 1 LSB register without updating the DAC output.
3 DAC1MSB
Loads DAC 1 MSB register without updating the DAC output.
4 DAC2LSB
Loads DAC 2 LSB register without updating the DAC output.
5 DAC2MSB
Loads DAC 2 MSB register without updating the DAC output.
6 DAC3LSB
Loads DAC 3 LSB register without updating the DAC output.
7 DAC3MSB
Loads DAC 3 MSB register without updating the DAC output.
8 RELAY0
Sets relay channels 0-7 simultaneously. All bits are active high.
RELAY0
Returns the states of relay channels 0-7. All bits are active high.
9 RELAY1
Sets relay channels 8-15 simultaneously. All bits are active high.
RELAY1
Returns the states of relay channels 8-15. All bits are active high.
A RELAY2
Sets relay channels 16-23 simultaneously. All bits are active high.
RELAY2
Returns the states of relay channels 16-23. All bits are active high.
B RESET
Force a local reset on the 421, returning it to its default power-up
state. All encoder counters are reset, and the watchdog timer and
DAC outputs are disabled. Relay channels are not affected.
STATUS
Returns 421 status. All status bits are active high. Status bits have
the following meanings: UN=A/D unipolar mode, DE=DAC chan-
nels enabled, BZ=A/D subsystem busy, FT=421 fault.
C CHCTRL
Select A/D channel or set hardware enables. M specifies opera-
tion: 0=select channel N
2
N
1
N
0
, 1=set enables: N
0
enables watch-
dog timer and N
1
enables DAC outputs.
ADLSB
Returns the least-significant data byte (lsb) from the last A/D con-
version. The lsb must be read before the msb to ensure proper
operation.
D ADSTART
Start an A/D conversion.
ADMSB
Returns the most-significant data nibble from the last A/D conver-
sion.
E CNTCTL
M
1
M
0
specifies counter operation: 00=latch counter S
1
S
0
,
01=reset counter S
1
S
0
, 1X=set mode M
0
S
1
S
0
. When S
1
S
0
selects
counter channel: 00=chan0, 01=chan1, 10=chan2, 11=not valid.
CNTLSB
Returns the least-significant byte from the encoder counter latch
register.
F HITDOG
Restart the watchdog timer.
CNTMSB
Returns the most-significant byte from the encoder counter latch
register.
d
7
d
6
d
5
d
4
d
3
d
2
d
1
d
0
x x x x x x x x
x x x x d
11
d
10
d
9
d
8
d
7
d
6
d
5
d
4
d
3
d
2
d
1
d
0
x x x x d
11
d
10
d
9
d
8
d
7
d
6
d
5
d
4
d
3
d
2
d
1
d
0
x x x x d
11
d
10
d
9
d
8
d
7
d
6
d
5
d
4
d
3
d
2
d
1
d
0
x x x x d
11
d
10
d
9
d
8
R
7
R
6
R
5
R
4
R
3
R
2
R
1
R
0
R
7
R
6
R
5
R
4
R
3
R
2
R
1
R
0
R
15
R
14
R
13
R
12
R
11
R
10
R
9
R
8
R
15
R
14
R
13
R
12
R
11
R
10
R
9
R
8
R
23
R
22
R
21
R
20
R
19
R
18
R
17
R
16
R
23
R
22
R
21
R
20
R
19
R
18
R
17
R
16
0 0 0 0 0 0 0 0 x x x x UN DE BZ FT
0 0 0 0 M N
2
N
1
N
0
d
7
d
6
d
5
d
4
d
3
d
2
d
1
d
0
0 0 0 0 0 0 0 0 0 0 0 0 d
11
d
10
d
9
d
8
0 0 0 0 M
1
M
0
S
1
S
0
c
7
c
6
c
5
c
4
c
3
c
2
c
1
c
0
0 0 0 0 0 0 0 0 c
15
c
14
c
13
c
12
c
11
c
10
c
9
c
8