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Introduction
____________________________
Figure 1-9. Extended Mode Bits.
TIMER Extended Mode Bits
BIT 7
BIT 6
0
0
0
1
1
0
1
1
The AD1200 card only has the ability to use the DAC0,
DAC1, DIGIN and DIGOUT ports with interrupt driven or
DMA outputs modes. The XMODE bits in the TIMER register
can be set to select one of these ports instead of the ADC
converter to be strobed by the pacer clock. The A/D modes are
selected when bits 6 & 7 of the TIMER register are both 0.
A/D Modes 0, 1, 2 & 3.
___________________ _
Mode 0, Single Conversions.
________________________ _
In Mode 0, each write to the ADGCR, the A/D Gain
Channel Register, register 1, generates an A/D strobe. The
following method should be used.
i)
The mode bits in the ADCSR, A/D Control Status
Register, register 0, should be set to 00, ie Mode 0.
This stops the pacer clock if it is running.
ii)
The channel and gain required is written into the ADGCR,
A/D Gain Channel register, register 1. This generates an
A/D strobe so starting an A/D conversion.
iii)
When the A/D Done bit is set the ADCLO and and then
the ADCHI data bytes may be read, either by programmed
i/o, an interrupt service routine or by the DMA controller.
iv)
The next A/D conversion may be started by generating an
A/D strobe by writing a new gain and channel to the
ADGCR register.
Chapter 1
Continuous Conversion Performed On
A/D Converter
DAC0
DAC1
DIGITAL I/O PORT
AD1200 Reference
AD1200 Card Only
Compatible Mode
Page 17
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