User`s guide

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Operation Theorem

Vout Vref

DAn

= − ×

4096

Where the Vref is the reference voltage, the Vout is the output voltage,

and the DAn is the digital value in D/A data registers.

Before performing the D/A conversion, users should care about the

D/A reference voltage, which set by the JP1. Please refer section 2.6

for jumper setting. The reference voltage will effect the output voltage.

If the reference voltage is -5V, the D/A output scaling will be 0~5V. If the

reference voltage is -10V, the D/A output scaling will be 0~10V. The

relationship of reference voltage and output range is summary in the

following table.

Reference Voltage DA Output Voltage Range

-5 V 0V ~ +5V

-10 V 0V ~ +10V

Note that the D/A registers are "double buffered", so that the D/A

analog output signals will not be updated until the high byte is written.

When write 12 bits data to D/A registers of the ACL-8111, the low

byte must be written before the high byte. This procedure can insure

a single step transition when the D/A conversion.

Note: when writing digital data to D/A register, the low byte data should

be written first, because the register will temporarily hold and

not released to output. After the high byte is written, both high

and low will add and passed to A/D converter.

4.3 Digital Input and Output

The ACL-8111 provides 16 digital input and 16 digital output channels

through the connector CN2 and CN3 on board. The digital I/O signal

are fully TTL/DTL compatible. The detailed digital I/O signal

specification can be referred in section 1.3.