A/D Mode Control Register - Omega Engineering OME-A8111 Hardware Manual

2.4.8 A/D Mode Control Register

(WRITE) Base+B : A/D Mode Control Register Format
Bit 7 Bit 6
X SI2
X=don't care
Mode Select
D2 D1 D0 Software Trig
0 0 0
0 0 1
0 1 0
1 1 0
X=disable
SI2 SI1
0 0
0 0
0 1
0 1
1 0
1 0
1 1
1 1
The A/D conversion operation can be divided into 2 stages, trigger stage and transfer
stage. The trigger stage will generate a trigger signal to the A/D converter and the transfer
stage will transfer the results to the CPU.
The trigger method may be an internal trigger or an external trigger. The internal
trigger can be a software trigger or a pacer trigger. The software trigger is very simple
but can not control the sampling rate very precisely. In software trigger mode, the
program issues a software trigger command (sec. 2.4.9) any time needed. Then the program
will poll the A/D status bit until the ready bit is 0 (sec. 2.4.2).
OME-A-8111 Hardware Manual (ver.1.1, Jul/2003)
Bit 5 Bit 4
SI1 SI0
Trigger Type
Pacer Trig
Select X
Select X
X Select
X Select
SI0 IRQ Level
0 IRQ2
1 Not used
0 IRQ2
1 IRQ3
0 IRQ4
1 IRQ5
0 IRQ6
1 IRQ7
Bit 3 Bit 2
X D2
Transfer Type
Software Interrupt
Select
Select
X
Select
Bit 1 Bit 0
D1 D0
X
X
X
Select
16