LTC3208 no-OS driver

See drivers/led/ltc3208 (doxygen) for the Doxygen documentation.

Supported Devices

LTC3208

Overview

The LTC3208 is a highly integrated multidisplay LED controller. The part contains a 1A high efficiency, low noise charge pump to provide power to the MAIN, SUB, RGB, CAM and AUX LED displays. The LTC3208 requires only small ceramic capacitors and one current set resistor to form a complete LED power supply and current controller

The maximum display currents are set by a single external resistor. Current for each LED is controlled by a precision internal current source. Dimming and On/Off for all displays is achieved via the I2C serial interface. 256 brightness levels are available for the MAIN and SUB displays. 16 levels are available for the RGB and CAM displays. Four AUX current sources can be independently assigned via the I2C port to the CAM, SUB, MAIN or AUX DAC controlled displays.

Applications

  • Video/Camera Phones with QVGA + Displays

LTC3208 Device Configuration

Driver Initialization

In order to be able to use the device, you will have to provide the support for the communication protocol (I2C) as mentioned above.

The first API to be called is ltc3208_init. Make sure that it returns 0, which means that the driver was initialized correctly.

4-bit LED Configuration

The following pairs share one register each pair to control the current level:

RED and GREEN - GREEN uses the hight bits and RED uses the low bits. BLUE and AUX - AUX uses the hight bits and BLUE uses the low bits.

The current level for cam is also split between the high current and low with CAM_HIGH using the hight bits and CAM_LOW using the low bits.

These current level can be controlled using ltc3208_set_4_bit_dac, where it selects which register to change using an enumeration of the registers.

8-bit LED Configuration

The MAIN and SUB LEDS uses 255 levels to control current.

These current level can be controlled using ltc3208_set_8_bit_dac, where it selects which register to change using an enumeration of the registers.

Device Options Configuration

The device can be forced to operate on a specific charge pump configuration, enable dropout signal, choose if cam high or low is used, and choose if ENRGBS pin controls RGB or SUB. This can be set individually via ltc3208_set_cpo_2x, ltc3208_set_1p5x, ltc3208_set_droupout_enable, ltc3208_set_cam_enable, ltc3208_set_sub_enable, or directly to the register via ltc3208_update_options.