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A1

B1

C1

D

A2

B2

C2

E

F or ALD

Intensity

I/O port

Voltage

V

OH

V

OL

100%

0%

8 ms

Approximately 25%

Approximately 75%

2 ms

8 ms

6 ms

Approximately

12.5%

Approximately 37.5%

1 ms

4 ms

8 ms

8 ms

8 ms

3 ms

Intensity

I/O port

Voltage

V

OH

V

OL

50%

0%

TCA6507

WITH INTENSITY CONTROL AND SHUTDOWN

SCPS164B – MAY 2007 – REVISED NOVEMBER 2007

Figure 7. LED Intensity Per Bank

Figure 8. Output Port Voltage vs LED Intensity, Maximum Intensity = 100%

Figure 9. Output Port Voltage vs LED Intensity, Maximum Intensity = 50%

The One-Shot / Master Intensity register (register 9) (see Table 16) is an 8-bit register with three functions.

Bits 0–3 set the master intensity value (ALD). It is a binary number between 0 and 15.

Bits 4–5 determine whether the maximum intensity of PWM0 and PWM1 is set by the programmed F value

(BRIGHT_F0 or BRIGHT_F1) or the master ALD value. The default value for these bits is 0. Bit 4 supports

PWM0 and bit 5 is for PWM1. If bit 4 (or bit 5) is 0, the maximum intensity value for PWM0 (or PWM1) is set by

the F value. If bit 4 (or bit 5) is 1, the maximum intensity value for PWM0 (or PWM1) is set by the master ALD

value. This allows the user to vary the brightness of all LEDs by changing a single register.

Bits 6–7 determine whether each PWM operates in normal or one-shot mode. Bit 6 supports PWM0 and bit 7 is

for PWM1. If bit 6 (or bit 7) is 0, PWM0 (or PWM1) operates in the normal mode where the LEDs goes through

the full intensity cycle defined by Table 15 and Figure 7. If bit 6 (or bit 7) is 1, PWM0 (or PWM1) operate in the

one-shot mode. In this mode, the LEDs can be used to create a single-shot lighting effect where the LED

intensity is valid for a particular segment of the cycle shown in Table 15 and Figure 7.

Copyright © 2007, Texas Instruments Incorporated

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