13

®

DAC1221

OUT MSB

OUT0

t

12

t

10

t

9

SDIO is an input

SDIO is an output

IN7

t

13

t

11

IN0

CS

SCLK

SDIO

Start

Writing

Start

Reading

External device

generates 8

serial clock cycles

and transmits

instruction register

data via SDIO

CS taken HIGH

for t

15 periods

minimum

(or CS tied LOW)

External device

generates n

serial clock cycles

and transmits

specified

register data

via SDIO

CS

state

More

instructions?

End

HIGH

Yes

No

LOW

No

Is next

instruction

a read?

Yes

CS

state

From Read

flowchart

HIGH

LOW

To Read

flowchart

External device

generates 8 serial

clock cycles and

transmits instruction

register data

via SDIO

SDIO input to

output transition

CS

state

More

instructions?

End

HIGH

Yes

No

LOW

No

Is next

instruction

a Write?

Yes

CS

state

To Write

flowchart

HIGH

LOW

To Write

flowchart

External device

generates n serial

clock cycles and

receives specified

register data via SDIO

SDIO transitions to

tri-state condition

CS taken HIGH

for t

15 periods

minimum

(or CS tied LOW)

FIGURE 9. SDIO Input to Output Transition Timing.

FIGURE 10. Flowchart for Writing and Reading Register Data.