Products, Inc Computer Hardware User Manual

2.8 D/A Conversion

The OME-A-822PGL/PGH provides two 12 bit D/A converters. Before

using the D/A converter function, you should address the following items:

z D/A output register, BASE+4/BASE+5/BASE+6/BASE+7, (sec. 2.4.3)

z JP1 jumper set to internal reference voltage -5V or -10V (sec. 2.3.1)

z JP2 jumper set to internal or external reference voltage (sec. 2.3.2)

z If JP2 is set to internal and JP1 is set to -5V, the D/A output range is 0 to 5V

z If JP2 is set to internal and JP1 is set to -10V, the D/A output range is 0 to 10V

z If JP2 is set to external, the external reference voltage can be AC/DC +/- 10V

The block diagram is given below:

OME-A-822PGL/PGH

D/A channel 0

Base+4/+5

Ref

JP1

JP2

-5/-10 V

Internal

Reference

D/A channel 1

Base+6/+7

Ref

CN3

D0..D7

9,10,14,28,29

Analog

Gnd

V0+ V0-

Vref0+ Vref0-

V1+ V1-

Vref1+

Vref1-

NOTE : The D/A output latch registers use a “double buffer” structure. The user must

send the low byte data first, then send the high byte data. If the user

only sends the high byte, the low byte data will be the previous value.

OME-A-822PGL/PGH Hardware Manual ---- 31