Datasheet

AD7734 Data Sheet
Rev. A | Page 16 of 32
I/O PORT REGISTER
8 Bits, Read/Write Register, Address 01h, Default Value 30h + Digital Input Value × 40h
The bits in this register are used to configure and access the digital I/O port on the AD7734.
Bit Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Mnemonic P0 P1 P0 DIR P1 DIR RDYFN 0 0 SYNC
Default P0 Pin P1 Pin 1 1 0 0 0 0
Bit Mnemonic Description
7, 6 P0, P1
When the P0 and P1 pins are configured as outputs, the P0 and P1 bits determine the pins’ output level. When
the P0 and P1 pins are configured as inputs, the P0 and P1 bits reflect the current input level on the pins.
5, 4 P0 DIR, P1 DIR These bits determine whether the P0 and P1 pins are configured as inputs or outputs. When set to 1, the
corresponding pin will be an input; when reset to 0, the corresponding pin will be an output.
3 RDYFN This bit is used to control the function of the
RDY
pin on the AD7734. When this bit is reset to 0, the
RDY
pin
goes low when any channel has unread data. When this bit is set to 1, the
RDY
pin will only go low if all
enabled channels have unread data.
2, 1 0 These bits must be 0 for proper operation.
0
SYNC
This bit enables the
SYNC
pin function. By default, this bit is 0 and
SYNC
/P1 can be used as a digital I/O pin.
When the SYNC bit is set to 1, the
SYNC
pin can be used to synchronize the AD7734 modulator and digital
filter with other devices in the system.
REVISION REGISTER
8 Bits, Read-Only Register, Address 02h, Default Value 02h + Chip Revision × 10h
Bit Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Mnemonic Chip Revision Code Chip Generic Code
Default x x x x 0 0 1 0
Bit Mnemonic Description
7–4 Chip Revision Code 4-Bit Factory Chip Revision Code
3–0 Chip Generic Code On the AD7734, these bits will read back as 02h.
TEST REGISTER
24 Bits, Read/Write Register, Address 03h
This register is used for testing the part in the manufacturing process. The user must not change the default configuration of this register.