IS31FL3737 Driver

I²C 12x12 LED matrix driver by Lumissil. Supports a maximum of four drivers, each controlling up to 144 single-color LEDs, or 48 RGB LEDs.

IS31FL3737 Datasheet

Usage

The IS31FL3737 driver code is automatically included if you are using the LED Matrix or RGB Matrix feature with the is31fl3737 driver set, and you would use those APIs instead.

However, if you need to use the driver standalone, add this to your rules.mk:

COMMON_VPATH += $(DRIVER_PATH)/led/issi
SRC += is31fl3737-mono.c # For single-color
SRC += is31fl3737.c # For RGB
I2C_DRIVER_REQUIRED = yes

Basic Configuration

Add the following to your config.h:

Define	Default	Description
IS31FL3737_SDB_PIN	Not defined	The GPIO pin connected to the drivers' shutdown pins
IS31FL3737_I2C_TIMEOUT	100	The I²C timeout in milliseconds
IS31FL3737_I2C_PERSISTENCE	0	The number of times to retry I²C transmissions
IS31FL3737_I2C_ADDRESS_1	Not defined	The I²C address of driver 0
IS31FL3737_I2C_ADDRESS_2	Not defined	The I²C address of driver 1
IS31FL3737_I2C_ADDRESS_3	Not defined	The I²C address of driver 2
IS31FL3737_I2C_ADDRESS_4	Not defined	The I²C address of driver 3
IS31FL3737_PWM_FREQUENCY	IS31FL3737_PWM_FREQUENCY_8K4_HZ	The PWM frequency of the LEDs (IS31FL3737B only)
IS31FL3737_SW_PULLUP	IS31FL3737_PUR_0_OHM	The SWx pullup resistor value
IS31FL3737_CS_PULLDOWN	IS31FL3737_PDR_0_OHM	The CSx pulldown resistor value
IS31FL3737_GLOBAL_CURRENT	0xFF	The global current control value

I²C Addressing

The IS31FL3737 has four possible 7-bit I²C addresses, depending on how the ADDR pin is connected.

To configure this, set the IS31FL3737_I2C_ADDRESS_n defines to one of the following in your config.h, where n denotes the driver index:

Define	Value
IS31FL3737_I2C_ADDRESS_GND	0x50
IS31FL3737_I2C_ADDRESS_SCL	0x55
IS31FL3737_I2C_ADDRESS_SDA	0x5A
IS31FL3737_I2C_ADDRESS_VCC	0x5F

PWM Frequency

The PWM frequency can be adjusted (for IS31FL3737B only) by adding the following to your config.h:

#define IS31FL3737_PWM_FREQUENCY IS31FL3737_PWM_FREQUENCY_8K4_HZ

Valid values are:

Define	Frequency
IS31FL3737_PWM_FREQUENCY_8K4_HZ	8.4 kHz (default)
IS31FL3737_PWM_FREQUENCY_4K2_HZ	4.2 kHz
IS31FL3737_PWM_FREQUENCY_26K7_HZ	26.7 kHz
IS31FL3737_PWM_FREQUENCY_2K1_HZ	2.1 kHz
IS31FL3737_PWM_FREQUENCY_1K05_HZ	1.05 kHz

De-Ghosting

These settings control the pullup and pulldown resistor values on the SWy and CSx pins respectively, for the purposes of eliminating ghosting. Refer to the datasheet (p. 23) for more information on how and why this occurs.

To adjust the resistor values, add the following to your config.h:

#define IS31FL3737_SW_PULLUP IS31FL3737_PUR_0_OHM
#define IS31FL3737_CS_PULLDOWN IS31FL3737_PDR_0_OHM

Valid values for IS31FL3737_SW_PULLUP are:

Define	Resistance
IS31FL3737_PUR_0_OHM	None (default)
IS31FL3737_PUR_0K5_OHM	0.5 kΩ
IS31FL3737_PUR_1K_OHM	1 kΩ
IS31FL3737_PUR_2K_OHM	2 kΩ
IS31FL3737_PUR_4K_OHM	4 kΩ
IS31FL3737_PUR_8K_OHM	8 kΩ
IS31FL3737_PUR_16K_OHM	16 kΩ
IS31FL3737_PUR_32K_OHM	32 kΩ

Valid values for IS31FL3737_CS_PULLDOWN are:

Define	Resistance
IS31FL3737_PDR_0_OHM	None (default)
IS31FL3737_PDR_0K5_OHM	0.5 kΩ
IS31FL3737_PDR_1K_OHM	1 kΩ
IS31FL3737_PDR_2K_OHM	2 kΩ
IS31FL3737_PDR_4K_OHM	4 kΩ
IS31FL3737_PDR_8K_OHM	8 kΩ
IS31FL3737_PDR_16K_OHM	16 kΩ
IS31FL3737_PDR_32K_OHM	32 kΩ

Global Current Control

This setting controls the current sunk by the CSx pins, from 0 to 255. By default, the value is the maximum (255), but if you need to lower it, add the following to your config.h:

#define IS31FL3737_GLOBAL_CURRENT 0xFF

ARM/ChibiOS Configuration

Depending on the ChibiOS board configuration, you may need to enable and configure I²C at the keyboard level.

LED Mapping

In order to use this driver, each output must be mapped to an LED index, by adding the following to your <keyboardname>.c:

const is31fl3737_led_t PROGMEM g_is31fl3737_leds[IS31FL3737_LED_COUNT] = {
/* Driver
 *   |  R         G         B */
    {0, SW1_CS1,  SW1_CS2,  SW1_CS3},
    // etc...
};

In this example, the red, green and blue channels for the first LED index on driver 0 all have their cathodes connected to the SW1 pin, and their anodes on the CS1, CS2 and CS3 pins respectively.

For the single-color driver, the principle is the same, but there is only one channel:

const is31fl3737_led_t PROGMEM g_is31fl3737_leds[IS31FL3737_LED_COUNT] = {
/* Driver
 *   |  V */
    {0, SW1_CS1},
    // etc...
};

These values correspond to the register indices as shown in the datasheet on page 15, figure 9.

API

struct is31fl3737_led_t

Contains the PWM register addresses for a single RGB LED.

Members

• uint8_t driver
  The driver index of the LED, from 0 to 3.
• uint8_t r
  The output PWM register address for the LED's red channel (RGB driver only).
• uint8_t g
  The output PWM register address for the LED's green channel (RGB driver only).
• uint8_t b
  The output PWM register address for the LED's blue channel (RGB driver only).
• uint8_t v
  The output PWM register address for the LED (single-color driver only).

---

void is31fl3737_init(uint8_t index)

Initialize the LED driver. This function should be called first.

Arguments

• uint8_t index
  The driver index.

---

void is31fl3737_write_register(uint8_t index, uint8_t reg, uint8_t data)

Set the value of the given register.

Arguments

• uint8_t index
  The driver index.
• uint8_t reg
  The register address.
• uint8_t data
  The value to set.

---

void is31fl3737_select_page(uint8_t index, uint8_t page)

Change the current page for configuring the LED driver.

Arguments

• uint8_t index
  The driver index.
• uint8_t page
  The page number to select.

---

void is31fl3737_set_color(int index, uint8_t red, uint8_t green, uint8_t blue)

Set the color of a single LED (RGB driver only). This function does not immediately update the LEDs; call is31fl3737_update_pwm_buffers() after you are finished.

Arguments

• int index
  The LED index (ie. the index into the g_is31fl3737_leds array).
• uint8_t red
  The red value to set.
• uint8_t green
  The green value to set.
• uint8_t blue
  The blue value to set.

---

void is31fl3737_set_color_all(uint8_t red, uint8_t green, uint8_t blue)

Set the color of all LEDs (RGB driver only).

Arguments

• uint8_t red
  The red value to set.
• uint8_t green
  The green value to set.
• uint8_t blue
  The blue value to set.

---

void is31fl3737_set_value(int index, uint8_t value)

Set the brightness of a single LED (single-color driver only). This function does not immediately update the LEDs; call is31fl3737_update_pwm_buffers() after you are finished.

Arguments

• int index
  The LED index (ie. the index into the g_is31fl3737_leds array).
• uint8_t value
  The brightness value to set.

---

void is31fl3737_set_value_all(uint8_t value)

Set the brightness of all LEDs (single-color driver only).

Arguments

• uint8_t value
  The brightness value to set.

---

void is31fl3737_set_led_control_register(uint8_t index, bool red, bool green, bool blue)

Configure the LED control registers for a single LED (RGB driver only). This function does not immediately update the LEDs; call is31fl3737_update_led_control_registers() after you are finished.

Arguments

• uint8_t index
  The LED index (ie. the index into the g_is31fl3737_leds array).
• bool red
  Enable or disable the red channel.
• bool green
  Enable or disable the green channel.
• bool blue
  Enable or disable the blue channel.

---

void is31fl3737_set_led_control_register(uint8_t index, bool value)

Configure the LED control registers for a single LED (single-color driver only). This function does not immediately update the LEDs; call is31fl3737_update_led_control_registers() after you are finished.

Arguments

• uint8_t index
  The LED index (ie. the index into the g_is31fl3737_leds array).
• bool value
  Enable or disable the LED.

---

void is31fl3737_update_pwm_buffers(uint8_t index)

Flush the PWM values to the LED driver.

Arguments

• uint8_t index
  The driver index.

---

void is31fl3737_update_led_control_registers(uint8_t index)

Flush the LED control register values to the LED driver.

Arguments

• uint8_t index
  The driver index.