The A/D Gain Channel Register; Bits 6 & 7. Gain Select. Read / Write; Figure 3-6. A/D Gain Channel Register - Brainboxes AD-593 User Manual

AD1200 Reference
____________________________

The A/D Gain Channel Register.

The A/D Gain Channel Register, ADGCR, is used to select
the input channel to the A/D converter and the gain applied to
the input signal by the programmable gain amplifier.
Note: The AD1221
programmable gain and ADGCR bits 6 & 7 always read
back as zero.
When in Mode 0, single conversion mode, then writing to the
A/D Gain Channel Register forces the A/D Converter to start its
next conversion. A short delay, 4uS, between writing the
ADGCR and the start of conversion signal is automatically
inserted by the AD12XX card to allow the channel select
circuitry and the Programmable Gain Amplifier output to
stabilise. This delay is not inserted in continuous A/D conversion
modes since the new channel information is written after the
sample and hold circuitry acquires the input voltage due to the
pacer clock strobe signal.
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Figure 3-6. A/D Gain Channel Register.

ADGCR A/D Gain Channel Register.
BIT 7
0219 Gain
Hex Select1 Select0 used
R/W
AD1221 & AD1220
DO NOT HAVE
PROGRAMMABLE
GAIN READ AS 0
Bits 6 & 7. Gain select. Read / Write. _______________________________ _
These two bits select the gain that the Programmable Gain
Amplifier applies to the input voltage. Thus the voltage applied
to the cards edge connector is multiplied by this gain value
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and
BIT 6 BIT 5 BIT 4
Gain not
R/W
AD1220 cards
BIT 3
not Channel Channel Channel Channel
used Select3 Select2 Select1 Select0
R/W
Register Map
do NOT
BIT 2 BIT 1
R/W R/W
Chapter 3
have
BIT 0
R/W