Figure 3-9. Adc Low Byte Input Register - Brainboxes AD-593 User Manual

Register Map
Reading the ADCHI register resets the A/D Done bit and so the
A/D converter can be retriggered to start performing its next
conversion. Reading the ADCLO register does not effect the
A/D Done bit. Since reading ADCHI clears A/D Done and
another reading may be triggered it is best to read ADCLO first
and then read ADCHI.
The ADCHI and ADCLO registers are READ ONLY, data
written to them actually goes to the D/A converter, DAC0 which
occupies the same i/o address space, and will eventually appear
as an analogue output voltage from this converter.
The 12 bit ADC converter value is obtained from:-
ADCDATA= ADCHI*256 + ADCLO.
The ADC data is in the form of right justified offset binary, ie
the lowest voltage gives a value of 000hex whilst the highest
voltage gives a value of FFFhex.
For Unipolar signals, ie 0 to +FULL_SCALE_VOLTS, the actual
ADC voltage is obtained from:-
ADCVOLT= (ADCDATA * FULL_SCALE_VOLTS ) /4096
For Bipolar
+FULL_SCALE_VOLTS, the actual ADC voltage is obtained
from:-
ADCVOLT= (ADCDATA-2048) *FULL_SCALE_VOLTS /2048
____________________________________ _

Figure 3-9. ADC Low Byte Input Register.

ADCLO Input Register.
BIT 7
021A ADC
Hex 7
Read
Chapter 3
signals,
BIT 6 BIT 5
ADC ADC
6 5
Read Read
ie -FULL_SCALE_VOLTS
BIT 4 BIT 3
ADC ADC
4 3
Read Read
AD1200 Reference
BIT 2 BIT 1
ADC ADC
2 1
Read Read
Page 61
to
BIT 0
ADC
0
Read