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AD1200 Reference
Register Types.
_____________ _
The registers fall into two types:-
1)
Control registers such as the ADCSR, ADGCR and the
TIMERXM register. The registers contain mainly read and
write bits. These registers determine the SOURCE of the
A/D converter input and the RATE at which data can be
read from, or written to, the other ports.
2)
Data input output ports such as the AD LO & HI input
registers, the DAC0 LO & HI output ports, the DAC1 LO
& HI output ports, the DIGITAL output port and the
DIGITAL input port. These registers are EITHER read OR
write.
In fact, the INPUT registers for the A/D converter are at
the same addresses as the OUTPUT registers for the D/A
converter DAC0. This causes no problem in practice since
the A/D converter is an input only device and DAC0 is an
output only device.
Read Write Assignments.
______________________
Not every register is a read and write register. The
DAC1LO register and the DAC1HI register are write only
registers. The Control Status Register is a mixture of read only
bits, write only bits and read & write bits. For example the A/D
Control Status Register has three read only bits giving the status
of the A/D converter, 1 write only bit to clear an A/D error and
4 read/write bits that determine how the A/D conversions are to
be performed.
The AD1200 register map has been chosen with the
following design considerations:-
i)
Efficient use of the PC's limited i/o space.
ii)
Compatibility with DT2811 card and its extensive software
support.
iii)
Compatibility with Asyst, Labtech and other third party
data acquisition packages.
Page 52
Register Map
Chapter 3
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