Output Transfer Functions - Measurement Computing CIO-DAC08/16 User Manual

In summary form, the registers and functions are listed in Table 4-2. Each register has
eight bits which may constitute a byte of data or eight individual bit functions.
ADDRESS
BASE + 0 D/A 0 Least Significant Byte
BASE + 1 D/A 0 Most Significant Byte
BASE + 2 D/A 1 Least Significant Byte
BASE + 3 D/A 1 Most Significant Byte
BASE + 4 D/A 2 Least Significant Byte
BASE + 5 D/A 2 Most Significant Byte
BASE + 6 D/A 3 Least Significant Byte
BASE + 7 D/A 3 Most Significant Byte
BASE + 8 D/A 4 Least Significant Byte
BASE + 9 D/A 4 Most Significant Byte
BASE + 10 D/A 5 Least Significant Byte
BASE + 11 D/A 5 Most Significant Byte
BASE + # And so on for each DAC
The DAC16 contains 32 registers (16 register pairs). The DAC08 contains 16
registers. Each register pair controls 1 D/A output.
Each DAC has two 8-bit registers which are used to control it. The first register
contains the least significant eight bits of D/A code and should be written first.
7 6
D8 D9
The second register contains the most significant eight bits of D/A code and should be
written to last. A write to this register will update the output of the D/A with all 16
bits of the D/A code contained in the two registers. If the simultaneous update jumper
is set for XFER, no update will occur until a read of any one of the DAC registers is
executed. Upon a read, all DACs will update together.
7 6
MSB D1

4.2 OUTPUT TRANSFER FUNCTIONS

To program a DAC, you must select the output you desire in volts, then apply a
transfer function to that value. The transfer function for code = output is:
The UNIPOLAR transfer function of the DAC is:
Table 4-2. Register Summary
WRITE FUNCTION
5 4
D10 D11
5 4
D2 D3
10
READ FUNCTION
Initiate simultaneous update.
Initiate simultaneous update.
Initiate simultaneous update.
Initiate simultaneous update.
Initiate simultaneous update.
Initiate simultaneous update.
Initiate simultaneous update.
Initiate simultaneous update.
Initiate simultaneous update.
Initiate simultaneous update.
Initiate simultaneous update.
Initiate simultaneous update.
Same.
3 2
D12 D13
3 2
D4 D5
1 0
D14 LSB
1 0
D6 D7