LP55231 datasheet(41/59 Pages) TI2

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LP55231

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SNOSCR5D – MARCH 2013 – REVISED DECEMBER 2016

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7.6.4.4 Wait

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

frozen.

NAME

VALUE (d)

DESCRIPTION

prescale

Divide master clock (32.7 kHz) 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 is = (time) × (prescale). Maximum 484 ms, minimum 0.488 ms.

7.6.5 LED Mapping Instructions

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

stored in the SRAM (program memory of the LP55231). LP55231 has three program execution engines which

can be mapped to 9 LED drivers. One engine can control one or multiple LED drivers. There are totally eleven

instructions for the engine-to-LED-driver control: mux_ld_start, mux_map_start, mux_ld_end, mux_sel, mux_clr,

mux_map_next, mux_map_prev, mux_ld_next, mux_ld_prev, mux_ld_addr and mux_map_addr.

7.6.5.1 MUX_LD_START; MUX_LD_END

Mux_ld_start and mux_ld_end define the mapping table location in the memory.

NAME

VALUE (d)

DESCRIPTION

SRAM address

0-95

Mapping table start/end address

7.6.5.2 MUX_MAP_START

Mux_map_start defines the mapping table start address in the memory, and the first row of the table is activated

(mapped) at the same time.

NAME

VALUE (d)

DESCRIPTION

SRAM address

0-95

Mapping table start address

7.6.5.3 MUX_SEL

With mux_sel instruction one, and only one, LED driver can be connected to a program execution engine.

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

from an LED, PWM register value still controls the LED brightness.

NAME

VALUE (d)

DESCRIPTION

LED select

0-16

0 = no drivers selected

1 = LED1 selected

2 = LED2 selected

...

9 = LED9 selected

7.6.5.4 MUX_CLR

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

value still controls the LED brightness.

7.6.5.5 MUX_MAP_NEXT

This instruction sets the next row active in the mapping table each time it is called. For example, if the 2nd row is

active at this moment, after mux_map_next instruction call the 3rd row is active. If the mapping table end

address is reached, activation rolls to the mapping table start address next time when the mux_map_next

instruction is called. The engine does not push a new PWM value to the LED driver output before set_pwm or

ramp instruction is executed. If the mapping has been released from an LED, the value in the PWM register still

controls the LED brightness.

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