Datasheet
REV. 0–12–
AD7738
Table VII. Register Summary
Addr Dir Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Register 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 RDY FN 0 0 SYNC
P0 Pin P1 Pin 1 1 0 0 0 0
Revision 02 R Chip Revision Code Chip Generic Code
xxxx00 01
Test 03 R/W 24 Bits Manufacturing Test Register
ADC Status 04 R RDY7 RDY6 RDY5 RDY4 RDY3 RDY2 RDY1 RDY0
000000 00
Checksum 05 R/W 16-Bit Checksum Register
ADC ZS Calibration 06 R/W 24-Bit ADC Zero-Scale Calibration Register
800000h
ADC FS 07 R/W 24-Bit ADC Full-Scale Register
800000h
Channel Data
1
08-0F R 16-/24-Bit Data Registers
8000h
Channel ZS Calibration
1
10–17 R/W 24-Bit Channel Zero-Scale Calibration Registers
800000h
Channel FS Calibration
1
18–1F R/W 24-Bits Channel Full-Scale Calibration Registers
200000h
Channel Status
1
20–27 R CH2 CH1 CH0 0/P0 RDY/P1 NOREF SIGN OVR
Channel Number 0 0 0 0 0
Channel Setup
1
28–2F R/W BUF OFF COM1 COM0 Stat. Opt. ENABLE RNG2 RNG1 RNG0
000000 00
Channel Conv. Time
1
30–37 R/W CHOP FW (7-Bit Filter Word)
1 11h
Mode
2
38–3F R/W MD2 MD1 MD0 CLKDIS DUMP Cont. RD 24/16 Bits CLAMP
000000 00
NOTES
1
The three LSBs of the register address, i.e., Bit 2, 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 eight address locations The address used to write the Mode register specifies
the ADC channel on which the mode will be applied. Address 38h only must be used for reading from the Mode register.
Table VIII. Operational Mode Summary
MD2 MD1 MD0 Mode
000 Idle Mode
001 Continuous Conversion Mode
010 Single Conversion Mode
011 Power-Down (Standby) Mode
100 ADC Zero-Scale Self Calibration
101 For Future Use
110 Channel Zero-Scale System Calibration
111 Channel Full-Scale System Calibration
Table IX. Input Range Summary
RNG2 RNG1 RNG0 Nominal Input Voltage Range
100± 2.5 V
1010 V to +2.5 V
000± 1.25 V
0010 V to +1.25 V
010± 0.625 V
0110 V to +0.625 V