VA

VD

COMA

COMD

ERRB

C3

BASE

IN

OUT

GND

LM2936-3.3

22µ

22

100n

100n

20

100

100n

3.3µ

2.2n

2.2n

2.2n

DAC161S997

1µ

100n

LOOP+

LOOP-

PZT3904

INT

µC

MSP430G2553_PW_2

CSB

SDO

SDI

SCLK

C2

C1

OUT

SPI

CSB

SDI

SDO

SPI Write n

Register Load

SCLK

Addr n

Data n

Prior Data

Prior Addr

8

1 2

9

24

XFER_REG

0x00FF

Data n

Addr n

8

1 2

9

24

Communication Error

Error reported to MCU

NOP

Addr n

Data n

0x00FF?

XFER_REG?

8

1 2

9

24

SPI Write n

Register Load

Addr n

Data n

Prior Data

Prior Addr

8

1 2

9

24

XFER_REG

0x00FF

Data n

Addr n

8

1 2

9

24

NOP

NOP

0xXXXX

0x00FF

XFER_REG

8

1 2

9

24

CSB

SDI

SDO

SPI Write n

Register Load ± Error Detected

SCLK

Addr n

Data n

Prior Data

Prior Addr

8

1 2

9

24

XFER_REG

0x00FF

Data n

Addr n

8

1 2

9

24

Communication Error

Error reported to MCU

25 26

48

Addr n

Data n

0X00FF

XFER_REG

Resend Register Load

Data OK, pull CSB high to complete

operation

XFER_REG

0x00FF

Data n

Addr n

8

1 2

9

24

Repeat Write n

NOP

NOP

0xXXXX

0x00FF

XFER_REG

8

1 2

9

24

Do Not pull CSB high

DAC161S997

SNAS621 – JUNE 2013

www.ti.com

Figure 20. Detection of error in Register Load

If a communication error occurs in the XFER_REG command, it is detected during the trailing NOP command

(see Figure 21). Although the register load is incomplete, the device has not changed operations. Repeat the

original data and XFER_REG command.

Figure 21. Detection of Error in Register Readback

Application Circuit Examples

Figure 22.

22

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