LP8501 datasheet(23/51 Pages) TI1

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LP8501

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SNVS548D – SEPTEMBER 2008 – REVISED AUGUST 2013

SET_PWM

This instruction is used for setting the PWM value on the outputs D1 to D9 without any ramps. Set PWM output

value from 0 to 255 with PWM value bits [7:0]. Instruction execution takes sixteen 32 kHz clock cycles (=488 µs).

Name

Value (d)

Description

PWM value

0 to 255

PWM output duty cycle 0 to 100%

WAIT

When a wait instruction is executed, the engine is set in a wait status, and the PWM values on the outputs are

frozen.

Name

Value (d)

Description

prescale

Divide master clock (32 768 Hz) by 16 which

means 0.488 ms cycle time

Divide master clock (32 768 Hz) by 512

which means 15.625 ms cycle time

time

1 — 31

Total wait time will be = (time) x (prescale).

Maximum 484 ms, minimum 0.488 ms

LED MAPPING INSTRUCTIONS

These commands define the engine-to-LED mapping. The mapping information is stored in a table, which is

stored in the SRAM (program memory of the LP8501). Mapping information can be located anywhere in SRAM

memory. LP8501 has three lighting engines (Engines) which can be mapped to 9 LED drivers or to one GPO pin.

One engine can control one or multiple LED drivers. There are totally seven commands for the engine-to-LED

driver control: mux_ld_start, mux_ld_end, mux_sel, mux_clr, mux_inc, mux_dec, mux_set. Note: the LED

mapping instructions do not update PWM values to LED outputs. PWM values are updated after ramp or

set_pwm instructions.

MUX_LD_START; MUX_LD_END

Mux_ld_start and mux_ld_ end define the mapping table location in the memory. With mux_ld_start instruction

the mapped row can be activated at the same time by setting map = 1.

Name

Value (d)

Description

map

Mapped row inactive

Set the mapped row active. MUX_LD_START only

SRAM address

0 - 95

Mapping table start/end address

MUX_SEL

With mux_sel instruction one, and only one, LED driver (or the GPO pin) can be connected to a lighting engine.

Connecting multiple LEDs to one engine is done with the mapping table. After the mapping has been released

from an LED, the PWM register value will still control the LED brightness. If the mapping is released from the

GPO pin, serial bus control takes over the GPO state.

Name

Value (d)

Description

LED select

0 - 16

0 = no drivers selected

1 = LED1 selected

2 = LED2 selected

...

9 = LED9 selected

16 = GPO

MUX _CLR

Mux_clr clears engine-to-driver mapping. After the mapping has been released from an LED, the PWM register

value will still control the LED brightness. If the mapping is released from the GPO pin, serial bus control takes

over the GPO state.

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