Datasheet

Data Sheet AD7294
Rev. H | Page 29 of 48
ADC Channel Allocation
The three channel address bits indicate which channel the result
in the result register represents. Table 13 details the channel ID bits
(S.E. indicates single-ended and DIFF indicates differential).
Table 13. ADC Channel Allocation
Function
Channel ID
CH
ID2
CH
ID1
CH
ID0
V
IN
0 (S.E.) or
V
IN
0 − V
IN
1 (DIFF)
0 0 0
V
IN
1 (S.E.) or
V
IN
1 − V
IN
0 (DIFF)
0 0 1
V
IN
2 (S.E.) or
V
IN
2 − V
IN
3 (DIFF)
0 1 0
V
IN
3 (S.E.) or
V
IN
3 − V
IN
2 (DIFF)
0 1 1
I
SENSE
1 1 0 0
I
SENSE
2 1 0 1
T
SENSE
1 1 1 0
T
SENSE
2 1 1 1
T
SENSE
1, T
SENSE
2 RESULT REGISTERS (0x02 AND 0x03)
Register T
SENSE
1 and Register T
SENSE
2 are 16-bit read only registers.
The MSB, D15 is the alert_flag bit whereas Bit D14 to Bit D12
contain the three ADC channel allocation bits. D11 is reserved
for flagging diode open circuits. The temperature reading from
the ADC is stored in an 11-bit twos complement format, D10 to
D0 (see Table 14 and Table 15). Conversions take place approx-
imately every 5 ms.
Table 14. T
SENSE
Register (First Read)
MSB LSB
D15 D14 D13 D12 D11 D10 D9 D8
Alert_Flag CH
ID2
CH
ID1
CH
ID0
B11 B10 B9 B8
Table 15. Register (Second Read)
MSB LSB
D7 D6 D5 D4 D3 D2 D1 D0
B7 B6 B5 B4 B3 B2 B1 B0
T
SENSE
INT RESULT REGISTER (0x04)
The T
SENSE
INT register is a 16-bit read-only register used to
store the ADC data generated from the internal temperature
sensor. Similar to the T
SENSE
1 and T
SENSE
2 result registers, this
register stores the temperature readings from the ADC in an 11-
bit twos complement format, D10 to D0, and uses the MSB as a
general alert flag. Bits[ D14:D11] are not used and are set to
zero. Conversions take place approximately every 5 ms. The
temperature data format in Table 16 also applies to the internal
temperature sensor data.
Temperature Value Format
The temperature reading from the ADC is stored in an 11-bit
twos complement format, D10 to D0, to accommodate both
positive and negative temperature measurements. The temper-
ature data format is provided in Table 16.
Table 16. T
SENSE
Data Format
Input D10 (MSB) D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 (LSB)
Value (°C)
−256 +128 +64 +32 +16 +8 +4 +2 +1 +0.5 +0.25