AD7280ABSTZ datasheet(43/48 Pages) AD

43 / 48 page

AD7280A

Rev. 0 | Page 43 of 48

Example 7: Self-Test Conversion on All Parts

Example 7 shows a self-test conversion routine for all parts in a

daisy chain.

To select the self-test conversion, set Bits[D15:D14] of the

control register to 1, and set Bits[D13:D12] of the control

0x01B81092 (see Table 29, Write 1).

Set Bit D0 of the control register to 1 on all parts. This

setting enables the daisy-chain register read operation on

all parts. The 32-bit write command is 0x01C2B6E2 (see

Table 29, Write 2).

The register address corresponding to the self-test

conversion should be written to the read register of all

parts (see Table 13 for register addresses). The 32-bit write

command is 0x038617CA (see Table 29, Write 3).

Program the CNVST control register to 0x02 on all parts

to allow conversions to be initiated using the CNVST pin.

The 32-bit write command is 0x03A0546A (see

Write 4).

Table 29

Initiate conversions through the falling edge of CNVST.

Allow sufficient time for the self-test conversions to be

completed plus tWAIT.

The CNVST control register should be programmed to

gate the CNVST signal on all parts. The 32-bit write

command is 0x03A0340A (see

, Write 5). This

write prevents unintentional conversions from being

initiated by noise or glitches on the

Table 29

CNVST pin. This write

also updates the on-chip output registers of all devices in

the daisy chain.

Apply a CS low pulse that frames 32 SCLKs to read back

the desired voltage. This frame should simultaneously

write the 32-bit command 0xF800030A, as described in

the

section (see

, Write 6).

Serial Interface

Table 29

Example 8: Software Reset on All Parts

Example 8 shows a software reset routine for all parts in a

daisy chain.

Set Bit D7 of the control register to 1 on all parts to place

the AD7280A into software reset. The 32-bit write command

is 0x01D2B412 (see Table 30, Write 1).

Set Bit D7 of the control register to 0 on all parts to take the

AD7280A out of software reset. The 32-bit write command

is 0x01C2B6E2 (see Table 30, Write 2).

Table 29. Example 7: Self-Test Conversion on All AD7280A Devices

Write Command

Device Address

Data

Write All

D11

8-Bit CRC

D2 to D0

32-Bit Write

Command

Write 1

00000

001101

11000000

00010010

010

0x01B81092

Write 2

00000

001110

00010101

11011100

010

0x01C2B6E2

Write 3

00000

011100

00110000

11111001

010

0x038617CA

Write 4

00000

011101

00000010

10000101

010

0x03A0546A

Write 5

00000

011101

00000001

10000001

010

0x03A0340A

Write 6

11111

000000

00000000

01100001

010

0xF800030A

Table 30. Example 8: Software Reset for All AD7280A Devices

Write Command

Device Address

Data

Write All

D11

8-Bit CRC

D2 to D0

32-Bit Write

Command

Write 1

00000

001110

10010101

10000010

010

0x01D2B412

Write 2

00000

001110

00010101

11011100

010

0x01C2B6E2

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