ADC

LP55281

www.ti.com

SNVS458B – JUNE 2007 – REVISED JUNE 2007

Figure 17. Principle of LED Connection to ADC

Table 5. LED Multiplexing (Register 12h)

MUX_LED[3:0]

Connection

0000

R1

0001

G1

0010

B1

0011

R2

0100

G2

0101

B2

0110

R3

0111

G3

1000

B3

1001

R4

1010

G4

1011

B4

1100

ALED

1101

-

1110

-

1111

Boost Output

LED TEST PROCEDURE

The test sequence consists of the basic setup and measurement phases for all RGB LEDs and Boost voltage.

Basic setup phase for the device:

1. Give reset to LP55281 (by power on, NRST pin or write any data to register 60h)

2. Set the preferred value for RED1 (write 3Fh, 7Fh, BFh or FFh to register 00h)

3. Set the preferred value for GREEN1 (write 3Fh, 7Fh, BFh or FFh to register 01h)

4. Set the preferred value for BLUE1 (write 3Fh, 7Fh, BFh or FFh to register 02h)

5. Set the preferred value for RED2 (write 3Fh, 7Fh, BFh or FFh to register 03h)

6. Set the preferred value for GREEN2 (write 3Fh, 7Fh, BFh or FFh to register 04h)

7. Set the preferred value for BLUE2 (write 3Fh, 7Fh, BFh or FFh to register 05h)

8. Set the preferred value for RED3 (write 3Fh, 7Fh, BFh or FFh to register 06h)

9. Set the preferred value for GREEN3 (write 3Fh, 7Fh, BFh or FFh to register 07h)

10. Set the preferred value for BLUE3 (write 3Fh, 7Fh, BFh or FFh to register 08h)

11. Set the preferred value for RED4 (write 3Fh, 7Fh, BFh or FFh to register 09h)

12. Set the preferred value for GREEN4 (write 3Fh, 7Fh, BFh or FFh to register 0Ah)

13. Set the preferred value for BLUE4 (write 3Fh, 7Fh, BFh or FFh to register 0Bh)

14. Set the preferred value for ALED (write 01h - FFh to register 0Ch)

Copyright © 2007, Texas Instruments Incorporated

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