LP5521 datasheet(24/51 Pages) TI2

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LP5521

SNVS441I – JANUARY 2007 – REVISED NOVEMBER 2016

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Table 12. ENABLE Register (00H) (continued)

NAME

BIT

DESCRIPTION

B_EXEC

1:0

B channel program execution

00b = Hold: Wait until current command is finished then stop while EXEC mode is hold. PC can be read

or written only in this mode.

01b = Step: Execute instruction defined by current B channel PC value, increment PC and change

B_EXEC to 00b (Hold)

10b = Run: Start at program counter value defined by current B channel PC value

11b = Execute instruction defined by current B channel PC value and change B_EXEC to 00b (Hold)

EXEC registers are synchronized to 32-kHz clock. Delay between consecutive I2C writes to ENABLE register

(00H) need to be longer than 488 μs (typ.).

7.5.2.3.1

DIRECT Control

When R, G or B channel mode is set to 11b, the LP5521 drivers work in direct control mode. LP5521 LED

channels can be controlled independently through I2C. For each channel there is a PWM control register and a

output current control register. With output current control register is set what is the maximum output current with

8-bit resolution, step size is 100 μA. Duty cycle can be set with 8-bit resolution. Direct control mode resets

respective channel’s PC. PWM control bits are presented in Table 13:

Table 13. R_PWM Register (02H), G_PWM Register (03H), B_PWM Register (04H):

NAME

BIT

DESCRIPTION

PWM

7:0

LED PWM value during direct control operation mode

0000 0000b = 0%

1111 1111b = 100%

If charge pump automatic gain change is used in this mode, then PWM values need to be written 0 before

changing the drivers’ operation mode to disabled (00b) to ensure proper automatic gain change operation.

7.5.3 LED Controller Programming Commands

LP5521 has three independent programmable channels (R, G, B). Trigger connections between channels are

common for all channels. All channels have own program memories for storing complex patterns. Brightness

control and patterns are done with 8-bit PWM control (256 steps) to get accurate and smooth color control.

Program execution is timed with 32 768 Hz clock. This clock can be generated internally or external 32 kHz clock

can be connected to CLK_32K pin. Using external clock enables synchronization of LED timing to this clock

rather than internal clock. Selection of the clock is made with address 08H bits INT_CLK_EN and CLK_DET_EN.

See External Clock Detection for details.

Supported commands are listed in Table 14. Command compiler is available for easy sequence

programming. With Command compiler it is possible to write sequences with simple ASCII commands,

which are then converted to binary or hex format. See application note "LP5521 Programming

Considerations" for examples of Command compiler usage.

Table 14. LED Controller Programming Commands

Command

Ramp

Wait

Pre-

scale

Step time

Sign

Increment (number of steps)

Set PWM

PWM Value

Go to

Start

Branch

Loop count

Step / command number

End

Int

Reset

Trigger

Wait for trigger on channels 5-0

Send trigger on channels 5-0

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