as2574b austriamicrosystems, as2574b Datasheet - Page 6

• Manufacturer Part Number: as2574b
• Description: 20 Number One Touch Dialler With Serial Bus For Display Driver
• Manufacturer: austriamicrosystems

Data Sheet
Serial Interface
The AS2574B supports a serial bus. The protocol
defines device that sends data onto the bus as a
transmitter, and the receiving device as the receiver. The
AS2574B is controlling the transfer and hence the
master. The display driver, AS2590, being controlled is
the slave.
Clock and Data Conventions
Data states on the SDA line can change only during SCL
Figure 1: Data Transmission
Rev. 1
SDA
SCL
START
BIT
No
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
1
2
3
4
5
6
7
8
9
Symbol/command
Temporary MF select
LS on
LS off
MT on
MT off
2nd on
2nd off
Set Clock
Start
Start copy
Start FIFO
Start timer
Blank all
Test mode
BIT 0
Pause
Recall
0
1
2
3
4
5
6
7
8
9
a
b
c
d
#
*
BIT 1 …
MSB
1
0
0
0
1
1
1
0
0
0
0
1
0
1
1
1
1
1
0
0
0
1
0
0
1
0
0
0
1
1
1
1
6
B3
1
0
0
0
0
0
0
1
1
0
0
1
1
0
0
0
0
1
0
1
1
1
1
1
1
1
1
1
0
0
1
0
low. SDA state changes during SCL high are reserved
for indicating start and stop conditions (see figure 1).
Start Condition
All commands are preceded by the start condition, which
is a high to low transition of SDA when SCL is high.
Stop Condition
All communications are terminated by a stop condition,
which is low to high transition of SDA when SCL is high.
… BIT 4
B2
1
0
1
0
0
1
0
0
1
0
1
1
1
1
0
0
0
0
0
1
0
0
0
1
1
0
1
1
0
1
1
1
B1
0
0
0
1
0
0
1
0
0
1
1
1
1
1
0
1
1
0
0
0
1
0
0
1
1
1
0
1
1
0
0
1
STOP BIT
LSB
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
HEX
1C
0C
0A
0E
1E
1A
1B
0B
0D
1D
00
04
02
10
14
12
08
06
16
18
19
01
05
03
11
09
07
1F
0F
13
15
17
AS2574B
WORD
GAP
Jan. 1995