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Revision 1.00

17 - 29

AS1520/AS1521

Starting a Conversion

A conversion is started by clocking a control byte into pin DIN.

With CSN low, each rising edge on SCLK clocks a bit from DIN into the internal shift register, starting with the MSB. A

conversion will only start when a logic 1 is written to the START bit of the 8-bit control register.

Figure 21. Single Conversion Timing Waveforms

Figure 22. Continuous 16-Clock Conversion Timing Waveforms

RANGE

B9

B8

B7

B6

B5

S0

S1

B0

B1

B2

B3

B4

RB1

RB2

RB3

Single Conversion

Acquire

Idle

Idle

1

4

8

9

12

20

16

24

Start

High-Z

High-Z

High-Z

High-Z

CSN

SCLK

DIN

SSTRB

DOUT

SEL2 SEL1 SEL0

MODE

PD0

PD1

High-Z

CSN

DIN

SSTRB

SCLK

B9

B9

B0

B4

B4

B4

B0

...

Conversion Result 0

Conversion Result 1

Control Byte 0

Control Byte 1

Control Byte 2

High-Z

B9

112

816 1

12

816 1

12

816

SS

S

S

DOUT

Conversion Result 2