DocID024501 Rev 2

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AN4290

Daisy chain

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Figure 9. Time diagram of a 3 slave daisy chain

The daisy chain configuration also allows a perfect synchronization in the execution of the

commands by the slave devices. Considering that all the devices acquire the respective

transmitted byte at the same time (raising edge of the CS line), the different devices can

start the execution of a command at the same time as shown in Figure 10.

Figure 10. Command synchronization example

MOSI

SDO

SDO

SDO

SDI

SDI

SDI

MISO

MOSI

SDO

SDO

SDO

SDI

SDI

SDI

MISO

MOSI

SDO

SDO

SDO

SDI

SDI

SDI

MISO

MOSI

SDO

SDO

SDO

SDI

SDI

SDI

MISO

CS

CK

CMD3

CMD3

CMD2

CMD2

ANS1

ANS1

CMD3

CMD3

ANS2

ANS2

Unknown

Don’t care

ANS1

ANS1

CMD2

CMD1

CMD1

ANS3

ANS3

ANS2

Master receives

answer byte

from device 2

Master receives

answer byte

from device 1

Slaves decodes the respective

SPI shift register content

Master receives

answer byte

from device 3

Device 1

SPI shift register

Device 2

SPI shift register

Device 3

SPI shift register

Master TX buffer

Master RX buffer

AM16753v1