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AS3931

Datasheet - Configuring the Product

9 Configuring the Product

9.1 Serial Programming Interface

The AS3931 is programmed via an unidirectional three wire Serial Programming Interface.The 3 lines are:

CS: Chip Select, used for selecting AS3931 and for data latching

SCL: Serial Clock

SDA: Serial Data

A block of 8 bit data starting with the LSB is sent according to the diagram shown in Figure 19. The received block of 8 bit data is shifted into an

8 bit latch. The two LSBs are register address bits and the remaining 6 bits are data bits. The register address bits A1 and A0 are decoded and

the 6 data bits are stored into one of three 6 bit registers with the falling edge of CS.

Figure 19. Protocol of 8 Bit Data Serial Transmission

9.2 Power On Register

Table 4. Register Data

Bit

POR state

Description

P0

1

Enable Channel 1

P1

1

Enable Channel 2

P2

1

Enable Channel 3

P3

1

Enable Regulator

P4

0

Antenna Rotator Bit 1

P5

0

Antenna Rotator Bit 2

Table 5. Register Address

Bit

Value

A0

0

A1

0

CS

SDA

ADDRESS

DATA

A0

A 1

D 0

D1

D 2

D3

D4

D5

D =T : TEST MODE REGISTER

SCL

D =P : POWER ON REGISTER

D =C : CHANNEL SELECT REGISTER

D = M: CORRELATOR MODE REGISTER