AAT1236 Analogic Corporation, AAT1236 Datasheet - Page 12

• Manufacturer Part Number: AAT1236
• Manufacturer: Analogic Corporation

I
Programmability
The current sink magnitude of each group and the
on/off status of each channel is controlled via an
I
which requires a master to initiate all the commu-
nications with the device. I
two active wire SDA (serial data line) and SCL
(serial clock line). Both wires are open drain and
require an external pull-up resistor to V
SDA pin serves the I/O function, and the SCL pin
controls and references the I
tocol is a bidirectional bus which allows both read
and write actions to take place; the AAT1236 sup-
ports the write protocol only. Since the protocol
has a dedicated bit for Read or Write (R/W), when
communicating with the AAT1236, this bit must be
set to "0."
I
and Register Data
After sending the device address, the I
should send an 8-bit register address and 8-bit data
for programming. The AAT1236 has two registers;
The Brightness Control Register determines the
percentage of the maximum current set by R
applied to each channel and the Channel Control
Register determines which channels are enabled or
disabled. The programming is as follows:
BR_CRTL – LED Brightness Control Register
(Address: 00h)
Control register BR_CRTL can be used to control
LED brightness for each group. Control bits BX3,
BX2, BX1, BX0 set the percentage of the maximum
LED level in Group B. Control bits AX3, AX2, AX1,
AX0 set the percentage of the maximum LED level
in Group A.
12
2
2
2
C serial interface. I
C Programming Register Address
C Serial Interface and
BR _ CTRL
Bit name
BX3
D7
BX2
D6
2
BX1
C is a widely used interface
D5
BX0
D4
2
C protocol consists of
2
C bus. The I
AX3
D3
AX2
D2
2
AX1
C master
D1
CC
2
. The
C pro-
AX0
D0
SET
High Efficiency White LED Drivers
CH_CRTL – Channel ON/OFF Control Register
(Address: 01h)
Control register CH_CRTL can be used to disable
(OFF) or enable (ON) individual channels.
Table 1: LED Current Setting as Percentage of
CH _ CTRL
Bit name
CH _ CTRL [BY1:BY2]
[BX3:BX0], [AX3:AX0]
[AY1:AY3]
CH _ CTRL
the Maximum Level Set by R
000
001
010
011
100
101
110
111
BR _ CTRL
for Backlight and Keypad
0000
0001
0010
0100
0101
1000
1001
1010
0011
0110
0111
1011
1100
1101
1110
D7
1111
00
01
10
11
–
D6
–
D5
–
OFF
OFF
OFF
OFF
A1
ON
ON
ON
ON
BY1
D4
BY2
All Outputs (%)
D3
OFF
OFF
ON
ON
B1
OFF
OFF
OFF
OFF
A2
ON
ON
ON
ON
AY1
D2
1236.2007.01.1.0
13.5
12.0
10.5
100
9.0
84
71
60
51
43
35
31
26
21
18
15
SET
AY2
D1
.
OFF
OFF
OFF
OFF
OFF
OFF
ON
ON
B2
A3
ON
ON
ON
ON
AY3
D0