D/a conversion, 8 d/a conversion – Omega ISA- BUS MULTI-FUNCTIONAL BOARD OME-A822PG User Manual

Page 33

Advertising
background image

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

30

31

32

9,10,14,28,29

Analog
Gnd

V0+ V0-

Vref0+ Vref0-

V1+ V1-

Vref1+

12

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

Advertising