AS3930 AMSCO [austriamicrosystems AG], AS3930 Datasheet - Page 15

• Manufacturer Part Number: AS3930
• Description: Single Channel Low Frequency Wakeup Receiver
• Manufacturer: AMSCO [austriamicrosystems AG]

AS3930
Data Sheet - D e t a i l e d D e s c r i p t i o n
Table 7. Default Values of Registers
8.3.1.3
This 4-wire interface is used by the Microcontroller (µC) to program the AS3930. The maximum clock operation frequency of the SDI is 2 MHz.
Table 8. Serial Data Interface (SDI) pins
Note: SDO is set to tristate if CS is low. In this way more than one device can communicate on the same SDO bus.
SDI Command Structure
To program the SDI the CS signal has to go high. A SDI command is made up by a two bytes serial command and the data is sampled on the
falling edge of SCLK. The
the SDI from the MSB (B15) to the LSB (B0).
Table 9. SDI Command Structure
The first two bits (B15 and B14) define the operating mode. There are three modes available (write, read, direct command) plus one spare (not
used), as shown in
Table 10. SDI Command Structure
In case a write or read command happens the next 5 bits (B13 to B9) define the register address which has to be written respectively read, as
shown in
Table 11. SDI Command Structure
www.austriamicrosystems.com/AS3930
R12<4:0>
R13<7:0>
B15
Register
B13
Mode
0
0
0
0
Name
SCLK
Table
SDO
SDI
CS
Serial Data Interface (SDI)
B14
11.
B15
0
0
1
1
Table
F_WAK
B13
Name
B12
0
0
0
0
10.
Register address / Direct Command
Table 9
B12
shows how the command looks like, from the MSB (B15) to LSB (B0). The command stream has to be sent to
Digital Input with pull down
Digital Input with pull down
Digital Input with pull down
Type
WR
B11
0
0
0
0
B11
Digital Output
Signal
Default
B10
Value
B14
B10
0
1
0
1
0
0
0
0
B9
B8
B9
Revision 1.0
0
0
1
1
B7
Signal Level
CMOS
CMOS
CMOS
CMOS
B8
B6
0
1
0
1
False wakeup register
B5
Description
Reserved
DIRECT COMMAND
Serial Data input for writing registers, data to
Serial Data output for received data or read
transmit and/or writing addresses to select
NOT ALLOWED
Register Data
B4
Clock for serial data read and write
WRITE
READ
Mode
value of selected registers
Read/Write register
B3
readable register
Description
Chip Select
R0
R1
R2
R3
B2
B1
15 - 33
B0