www.austriamicrosystems.com/AS3932

Revision 1.2

15 - 33

AS3932

8.3.3 Serial Data Interface (SDI)

This 4-wires interface is used by the Microcontroller (µC) to program the AS3932. The clock operation frequency of the SDI is 1MHz.

Note:

SDO is set to tristate if CS is low. In this way more than one device can communicate on the same SDO bus.

R4<7:6>

T_OFF

W

00

Off time in ON/OFF operation mode

T_OFF=00

1ms

T_OFF=01

2ms

T_OFF=10

4ms

T_OFF=11

8ms

R4<5:4>

D_RES

W

01

Antenna damping resistor (see Table 15)

R4<3:0>

GR

W

0000

Gain reduction (see Table 14)

R5<7:0>

TS2

W

01101001

2

R6<7:0>

TS1

W

10010110

1

R7<7:5>

T_OUT

W

000

Automatic time-out (see Table 20)

R7<4:0>

T_HBIT

W

01011

Bit rate definition (see Table 18)

R8<2:0>

T_AUTO

W

000

Artificial wake-up

T_AUTO=000

No artificial wake-up

T_AUTO=001

1 sec

T_AUTO=010

5 sec

T_AUTO=011

20 sec

T_AUTO=100

2 min

T_AUTO=101

15min

T_AUTO=110

1 hour

T_AUTO=111

2 hour

R9<6:0>

000000

Reserved

R10<4:0>

RSSI1

R

RSSI channel 1

R11<4:0>

RSSI3

R

RSSI channel 3

R12<4:0>

RSSI2

R

RSSI channel 2

R13<7:0>

F_WAK

WR

False wakeup register

Table 8. Serial Data Interface (SDI) pins

Name

Signal

Signal Level

Description

CS

Digital Input with pull down

CMOS

Chip Select

SDI

Digital Input with pull down

CMOS

Serial Data input for writing registers, data to

transmit and/or writing addresses to select

readable register

SDO

Digital Output

CMOS

Serial Data output for received data or read

value of selected registers

SCLK

Digital Input with pull down

CMOS

Clock for serial data read and write

Table 7. Default Values of Registers

Register

Name

Type

Default

Value

Description