Diamond Systems 16-Channel 12-Bit Analog Output PC/104 Module 사용자 설명서

11. HOW TO GENERATE AN ANALOG OUTPUT

This chapter describes how to generate an analog output directly (without the use of the driver software).
Ruby-MM-1612 has 12-bit resolution analog outputs. However, data is written to the board in 8-bit bytes.
Therefore two bytes must be written to the board to generate a single analog output. In addition, many
applications require several channels to be updated simultaneously. In order to provide this ability, the
update operation is separate from the data write operation.
Thus there are three steps required to generate an analog output. Each step is described in detail. The
steps must be completed in the sequence shown below.

To generate an analog output on one or more channels:

1. Write the LSB (least significant byte) to the board at register Base + 0.
2. Write the channel number to the board at register Base + 2..
3. Write the MSB (most significant byte) to the board.
4. Repeat steps 1-3 for each channel to be changed

5. Update all changed channels by reading Base + 0 or Base + 1.

Hardware Update Command

A hardware update command can occur with a falling edge on the external trigger, pin 48 of J3.
To use hardware updating, or triggering, you must program the TRIGEN bit at Base + 3. See Chapter 3
for details.

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Note: When a channel is updated, its output will change only if new data has been written to it since

the last update. For example, if you do a simultaneous update on all channels but you only wrote data to
channel 0, then only channel 0 will change, and channels 1 - 15 will stay the same.

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Note: If hardware updating is enabled, software updating will still work.