2.7 A/D Conversion
This section explains how to use A/D conversions. The A/D conversion can
be triggered in any of 3 ways,
by software trigger, by pacer trigger or by
external trigger
to the A/D converter. At the end of A/D conversion, it is
possible to transfer data by one of 3 way, those are
polling, interrupt and
DMA.
Before using the A/D conversion function, user should notice the
following issue:
A/D data register, BASE+4/BASE+5, store the A/D conversion data
A/D gain control register, BASE+9, select gain
A/D multiplex control register, BASE+A, select analog input
A/D mode control register, BASE+B, select trigger type and transfer
type A/D software trigger control register, BASE+C
JP8 select internal/external trigger
JP5 select IRQ level
JP9 select internal/external clock for counter0
JP6, JP7 select DMA channel
3 trigger logic : software, pacer, external trigger
3 transfer logic : polling, interrupt, DMA
The block diagram is given below:
A-812PG
CN1
CN2
16 CH.
Multi-
plexer
Gain
Control
12 bits
A/D
Buffer
Memory
Transfer
Logic
CPU
Trigger
Logic
Base+9
Base+A
JP5
JP6
JP7
JP8
Base+B
Base+C
A-812PG Hardware Manual (Ver.1.2, Sep/2005, IPH-004-12) -----
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