AD5174

Rev. 0 | Page 14 of 20

SHUTDOWN MODE

The AD5174 can be shut down by executing the software

shutdown command, Command 9 (see Table 6), and setting

the LSB to 1. This feature places the RDAC in a zero-power-

consumption state where Terminal A is open circuited and

the wiper terminal, W, remains connected. It is possible to

execute any command from Table 6 while the AD5174 is in

shutdown mode. The parts can be taken out of shutdown

mode by executing Command 9 and setting the LSB to 0

or by a software reset, Command 4 (see Table 6).

RESET

The AD5174 can be reset through software by executing Com-

mand 4 (see Table 6). The reset command loads the RDAC

register with the contents of the most recently programmed 50-TP

memory location. The RDAC register loads with midscale if no

50-TP memory location has been previously programmed.

Table 7. Write and Read to RDAC and 50-TP Memory

DIN

SDO1

Action

0x1C03

0xXXXX

Enable update of the wiper position and the 50-TP memory contents through the digital interface.

0x0500

0x1C03

Write 0x100 to the RDAC register; wiper moves to ¼ full-scale position.

0x0800

0x0500

Prepares data read from RDAC register.

0x0C00

0x100

Stores RDAC register content into the 50-TP memory. A 16-bit word appears out of SDO, where the last 10 bits contain

the contents of the RDAC register (0x100).

0x1800

0x0C00

Prepares data read of the last programmed 50-TP memory monitor location.

0x0000

0xXX19

NOP Instruction 0 sends a 16-bit word out of SDO, where the six LSBs (that is, last six bits) contain the binary address of

the last programmed 50-TP memory location, for example, 0x19 (see Table 10).

0x1419

0x0000

Prepares data read from Memory Location 0x19.

0x2000

0x0100

Prepares data read from the control register. Sends a 16-bit word out of SDO, where the last 10 bits contain the

contents of Memory Location 0x19.

0x0000

0xXXXX

NOP Instruction 0 sends a 16-bit word out of SDO, where the last four bits contain the contents of the control register.

If Bit C2 = 1, the fuse program command was successful.

Table 8. Control Register Bit Map

D9

D8

D7

D6

D5

D4

D3

D2

D1

D0

0

0

0

0

0

0

C2

0

C1

C0

Table 9. Control Register Bit Description

Bit Name

Description

C0

50-TP program enable

0 = 50-TP program disabled (default)

1 = enable device for 50-TP program

C1

RDAC register write protect

0 = wiper position frozen to value in 50-TP memory (default)1

1 = allow update of wiper position through digital interface

C2

50-TP memory program success bit

0 = fuse program command was unsuccessful (default)

1 = fuse program command was successful