Datasheet
AD7734 Data Sheet
Rev. A | Page 14 of 32
REGISTER DESCRIPTION
Table 11. Register Summary
Register Addr Dir Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
(hex) Default Value
Communications 00 W 0
R/
W
6-Bit Register Address
I/O Port 01 R/W P0 P1 P0 DIR P1 DIR RDYFN 0 0 SYNC
P0 Pin P1 Pin 1 1 0 0 0 0
Revision 02 R Chip Revision Code Chip Generic Code
x x x x 0 0 1 0
Test 03 R/W 24-Bit Manufacturing Test Register
ADC Status 04 R – – – – RDY3 RDY2 RDY1 RDY0
0 0 0 0 0 0 0 0
Checksum 05 R/W 16-Bit Checksum Register
ADC Zero-Scale Calibration 06 R/W 24-Bit ADC Zero-Scale Calibration Register
800000h
ADC Full-Scale
07
R/W
24-Bit ADC Full-Scale Register
800000h
Channel Data
1
08–0B R 16-/24-Bit Data Registers
8000h
Channel Zero-Scale Cal.
1
10–13 R/W 24-Bit Channel Zero-Scale Calibration Registers
800000h
Channel Full-Scale Cal.
1
18–1B R/W 24-Bit Channel Full-Scale Calibration Registers
200000h
Channel Status
1
20–23 R 0 CH1 CH0 0/P0 RDY/P1 NOREF SIGN OVR
Channel Number 0 0 0 0 0
Channel Setup
1
28–2B R/W 0 0 0 Stat OPT ENABLE 0 RNG1 RNG0
0 0 0 0 0 0 0 0
Channel Conversion Time
1
30–33 R/W CHOP FW (7-Bit Filter Word)
1 11h
Mode
2
38–3B R/W MD2 MD1 MD0 CLKDIS DUMP Cont RD 24/16 BIT CLAMP
0 0 0 0 0 0 0 0
1
The two LSBs of the register address, i.e., Bit 1 and Bit 0 in the communication register, specify the channel number of the register being accessed.
2
There is only one mode register, although the mode register can be accessed in one of four address locations. The address used to write the mode register specifies
the ADC channel on which the mode will be applied. Only address 38h must be used for reading from the mode register.
Table 12. Operational Mode Summary
MD2 MD1 MD0 Mode
0
0
0
Idle Mode
0 0 1 Continuous Conversion Mode
0 1 0 Single Conversion Mode
0 1 1 Power-Down (Standby) Mode
1 0 0 ADC Zero-Scale Self-Calibration
1 0 1 For Future Use
1 1 0 Channel Zero-Scale System Calibration
1 1 1 Channel Full-Scale System Calibration
Table 13. Input Range Summary
RNG1 RNG0 Nominal Input Voltage Range
0
0
±10 V
0 1 0 V to +10 V
1 0 ±5 V
1 1 0 V to +5 V