Matrix - LED

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Introduction

LED
LED
LED

The Matrix-LED is an LED module with three 2.54 mm spacing pins: V(supply voltage),G(ground) and S(signal) which is connected to a triode to turn the LED on or off. You can write high or low, or PWN signals(3.3V or 5V) to S. When you write high to S the LED will turn on and become brightest. When you write low to S the LED will turn off. If you write PWM signals to S the LED's brightness will vary depending on the PWM's signal variances.

Features

  • GPIO/PWM interface, 3.3/5V, PWM brightness control
  • Small, easy to be used in various situations
  • 2.54 mm spacing pin
  • PCB Dimension(mm): 8 x 24

LED-01.PCB

  • Pin Description:
Pin Description
S GPIO
V Supply Voltage 5V
G Ground

Basic Device Operation

The module has three 2.54 mm spacing pins: V(supply voltage),G(ground) and S(signal) which is connected to a triode to turn the LED on or off. You can write high or low, or PWN signals(3.3V or 5V) to S. When you write high to S the LED will turn on and become brightest. When you write low to S the LED will turn off. If you write PWM signals to S the LED's brightness will vary depending on the PWM's signal variances.

Applications

Connect to NanoPi M1

Refer to the following connection diagram to connect the module to the NanoPi M1:
Matrix-LED_nanopi_m1

Connection Details:

Matrix-LED NanoPi M1
S Pin7
V Pin4
G Pin6

Connect to NanoPi 2

Refer to the following connection diagram to connect the module to the NanoPi 2:
Matrix-LED_nanopi_2

Connection Details:

Matrix-LED NanoPi 2
S Pin7
V Pin4
G Pin6

Connect to NanoPi M2 / NanoPi 2 Fire

Refer to the following connection diagram to connect the module to the NanoPi M2/ NanoPi 2 Fire:
Matrix-LED_nanopi_m2

Connection Details:

Matrix-LED NanoPi M2
S Pin7
V Pin4
G Pin6

Connect to NanoPC-T2

Refer to the following connection diagram to connect the module to the NanoPC-T2:
Matrix-LED_NanoPC-T2

Connection Details:

Matrix-LED NanoPC-T2
S Pin15
V Pin29
G Pin30

Compile & Run Test Program

Boot your ARM board with Debian and copy the matrix code:

$ apt-get update && apt-get install git
$ git clone https://github.com/friendlyarm/matrix.git

If your cloning is done successfully a "matrix" directory will be generated.

Compile and install Matrix:

$ cd matrix
$ make && make install

Run test program:

$ matrix-gpio_out

Note: this module is not plug and play therefore before running the module please make sure it is connected to an ARM board.
Here is what you should observe:

1: gpio status change
2: gpio status change
3: gpio status change
4: gpio status change
5: gpio status change

The LED will be blinking continuously.

Code Sample

This Matrix code sample can work with all the ARM boards mentioned in this module's wiki. The name of this code sample is "matrix-gpio_out". Here is its source code:

int main(int argc, char ** argv) 
{
    int pin = GPIO_PIN(7); 
    int i, value, board;
    int ret = -1;
 
    if ((board = boardInit()) < 0) {
        printf("Fail to init board\n");
        return -1;
    }
    if (board == BOARD_NANOPI_T2)
        pin = GPIO_PIN(15);
 
    if (argc == 2)
        pin = GPIO_PIN(atoi(argv[1]));
    if ((ret = exportGPIOPin(pin)) == -1) {   
        printf("exportGPIOPin(%d) failed\n", pin);
    }
    if ((ret = setGPIODirection(pin, GPIO_OUT)) == -1) {
        printf("setGPIODirection(%d) failed\n", pin);
    }
    for (i = 0; i < STATUS_CHANGE_TIMES; i++) {
        if (i % 2) {
            value = GPIO_HIGH;
        } else {
            value = GPIO_LOW;
        }
        if ((ret = setGPIOValue(pin, value)) > 0) {
            printf("%d: GPIO_PIN(%d) value is %d\n", i+1, pin, value);
        } else {
            printf("setGPIOValue(%d) failed\n", pin);
        }
        sleep(1);
    }
    unexportGPIOPin(pin);
    return 0;
}

For more details about this APIs called in this code sample refer to Matrix API reference manual

Resources

Update Log

Feb-18-2016

  • Added the description for "NanoPi 2 branch" in Section 4
  • Added Section 5: Connect to NanoPi 2

June-21-2016

  • Re-organized and simplified wiki