TCA6507_10 Datasheet, PDF (23/32 Pages) Texas Instruments – LOW-VOLTAGE 7-BIT I2C AND SMBus LED DRIVER WITH INTENSITY CONTROL AND SHUTDOWN

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TCA6507
LOW-VOLTAGE 7-BIT I²C AND SMBus LED DRIVER
WITH INTENSITY CONTROL AND SHUTDOWN
SCPS164B – MAY 2007 – REVISED NOVEMBER 2007
SOFTWARE CONSIDERATIONS FOR USING THE TCA6507
Operation
The TCA6507 includes 11 registers that control the LED function and intensity. In general, the TCA6507 needs to
be operated/written this way to run LEDs (see Figure 11).
1. Master sends a START condition.
2. Master sends the slave address with a write operation (1000 1010).
3. Master sends a command byte that points 1 of the 11 registers in this device.
4. Master sends data to the TCA6507 register(s).
If auto-increment mode is used, the master can write to all 11 registers with 1 command byte being sent initially.
After all registers are written to (if needed), LEDs operate after the TCA6507 acknowledges the master’s
command.
Auto-Increment Mode
In auto-increment mode, the last four bits of the command byte are automatically incremented after the byte is
written and the next data byte is stored in the corresponding register.
Device Address:
0001 0000, 0X02, 0X02, 0X02
Command byte:
B4 = 1 enables auto-increment mode
B3–B0 = 0000 points to Select0 register
Data byte write to Select2 register
Data byte write to Select1 register
Data byte write to Select0 register
The registers are written to in the order shown in Table 3.
LED Operation
For LED states, see Figure 1 and Table 4.
It is the combination of Select2, Select1, and Select0 registers that gives the state of the LED or Px.
Bit 0 from the Select0 register, bit = 0 from Select1 register and bit=0 from the Select2 register provide the state
for P0 or the first LED. Similarly, bit = 1 from the Select0 register, bit 1 from Select1 register and bit = 1 from the
Select2 register provide the state for P1 or the second LED (see Table 20).
Select0
Select1
Select2
Output or
LED affected
MSB
X
X
X
X
X
Table 20. LED Operation
0
0
0
P6
7th LED
0
0
0
P5
6th LED
0
0
0
P4
5th LED
0
0
0
P3
4th LED
0
0
0
P2
3rd LED
0
0
0
P1
2nd LED
LSB
0
0
0
P0
1st LED
Example of LED Operation
Starting with a powerup/reset and all seven LEDs off, the following is an example of LED operationg(using
auto-increment):
<start>, …,
Start,
<slave addr>,
1000 1010,
<command with auto-increment>,
0001 0000,
<data>, <data>, <data>, <stop>
0X02, 0X02, 0X02, Stop
Copyright © 2007, Texas Instruments Incorporated
Product Folder Link(s): TCA6507
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