Datasheet

REV. 0–16–
AD7738
Channel Status Registers
8 Bits, Read-Only Register, Address 20h–27h, Default Value 20h  Channel Number
These registers contain individual channel status information and some general AD7738 status information. Reading the Status
registers can be associated with reading the Data registers in the Dump mode. Reading the Status registers is always associated with
reading the Data registers in the Continuous Read mode. See the Digital Interface Description section for more details.
Bit Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Mnemonic CH2 CH1 CH0 0/P0 RDY/P1 NOREF SIGN OVR
Default Channel Number 0 0 0 0 0
Bit Mnemonic Description
7–5 CH2–CH0 These bits reflect the channel number. This can be used for current channel identification and easier
operation in the Dump mode and Continuous Read mode.
40/P0 When the Status Option bit in the corresponding Channel Setup register is reset to 0, this bit is read
as a zero. When the Status Option bit in set to 1, this bit reflects the state of the P0 output pin.
3 RDY/P1 When the Status Option bit in the corresponding Channel Setup register is reset to 0, this bit reflects the
selected channel RDY bit in the ADC Status register. When the Status Option bit is set to 1, this
bit reflects the state of the P1 pin whether it is configured as an input or output.
2 NOREF This bit indicates the reference input status. If the voltage between the REFIN+ and REFIN– pins is less
than the NOREF trigger voltage, then the NOREF bit goes to a 1.
1 SIGN The voltage polarity at the analog input. Will be 0 for a positive voltage; will be 1 for a negative voltage.
0 OVR This bit reflects either overrange or underrange on an analog input. The bit is set to 1 when the analog
input voltage goes over or under the Nominal Voltage Range. See the Analog Inputs Extended Voltage
Range section.