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SOFTWARE CONSIDERATIONS FOR USING THE TCA6507

Operation

Auto-Increment Mode

Device Address:

,

,

,

Command byte:

B4 = 1 enables auto-increment mode

B3–B0 = 0000 points to Select0 register

Data byte write to Select0 register

Data byte write to Select1 register

Data byte write to Select2 register

LED Operation

Example of LED Operation

<command with auto-increment>,

<data>,

<data>,

<data>,

<stop>

<slave addr>,

<start>, …,

0001 0000,

0X02,

0X02,

0X02,

Stop

1000 1010,

Start,

TCA6507

WITH INTENSITY CONTROL AND SHUTDOWN

SCPS164B – MAY 2007 – REVISED NOVEMBER 2007

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.

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.

The registers are written to in the order shown in Table 3.

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).

Table 20. LED Operation

MSB

LSB

Select0

X

0

0

0

0

0

0

0

Select1

X

0

0

0

0

0

0

0

Select2

X

0

0

0

0

0

0

0

Output or

X

P6

P5

P4

P3

P2

P1

P0

LED affected

X

7th LED

6th LED

5th LED

4th LED

3rd LED

2nd LED

1st LED

Starting with a powerup/reset and all seven LEDs off, the following is an example of LED operationg(using

auto-increment):

Copyright © 2007, Texas Instruments Incorporated

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