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Configuring the I/O of the CDS-3310
The 40 extended I/O points of the CDS-3310 series controller can be configured in banks of 8. The
extended I/O is denoted as banks 2-6 or bits 17-56.
The command, CO, is used to configure the extended I/O as inputs or outputs. The CO command has
one field:
where n is a decimal value which represents a binary number. Each bit of the binary number
represents one bank of extended I/O. When set to 1, the corresponding bank is configured as an
output.
The least significant bit represents bank 2 and the most significant bit represents bank 9. The decimal
value can be calculated by the following formula. n = n
represents the bank. If the n
output. If the n
example, if bank 4 and 5 is to be configured as an output, CO 12 is issued.
8-Bit I/O Bank
The simplest method for determining n:
Step 1. Determine which 8-bit I/O banks to be configured as outputs.
Step 2. From the table, determine the decimal value for each I/O bank to be set as an output.
Step 3. Add up all of the values determined in step 2. This is the value to be used for n.
For example, if banks 2 and 3 are to be outputs, then n is 3 and CO3 should be issued. NOTE: This
calculation is identical to the formula: n = n
bank.
Saving the State of the Outputs in Non-Volatile Memory
The configuration of the extended I/O and the state of the outputs can be stored in the EEPROM with
the BN command. If no value has been set, the default of CO 0 is used (all banks are inputs).
Accessing Extended I/O
When configured as an output, each I/O point may be defined with the SBn and CBn commands
(where n=1 through 8 and 17 through 56). Outputs may also be defined with the conditional
command, OBn (where n=1 through 8 and 17 through 56).
The command, OP, may also be used to set output bits, specified as banks of data. The OP command
accepts 5 parameters. The first parameter sets the values of the main output port of the controller
(Outputs 1-8, bank 0). The additional parameters set the value of the extended I/O as outlined:
OP m,a,b,c,d
54 • Chapter 7 Application Programming
CO n
value is a one, then the bank of 8 I/O points is to be configured as an
x
value is a zero, then the bank of 8 I/O points will be configured as an input. For
x
Bank
17-24
2
25-32
3
33-40
4
41-48
5
49-56
6
+ 2*n
+ 4*n
2
3
Binary
Representation
0
2
1
2
2
2
3
2
4
2
+ 2*n
+ 4*n
+ 8*n
2
3
4
5
+ 8*n
+16* n
where n
4
5
6
Decimal Value for
Bank
1
2
4
8
16
+16* n
where n
represents the
6
x
x
CDS-3310
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