Matrix - Button

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1 Introduction

Button

• The Matrix-Button module is used to detect button events.
• If the button is not pressed S will output high otherwise S will output low.

2 Features

• 3 PIN interface
• PCB dimension (mm): 8 x 24

• Pin Description:

Pin	Description
S	GPIO
V	Supply Voltage 5V
G	Ground

3 Basic Device Operation

• The Matrix-Button is an instant(non self-lock) button. The button's status can be read from pin S in the 3-pin 2.54 mm spacing pin header.
• If the button is not pressed S will output high otherwise S will output low.

4 硬件连接

4.1 连接NanoPi M1

参考下图连接模块：

连接说明：

Matrix-Button	NanoPi M1
S	Pin7
V	Pin4
G	Pin6

4.2 连接NanoPi 2

参考下图连接模块：

连接说明：

Matrix-Button	NanoPi 2
S	Pin7
V	Pin4
G	Pin6

4.3 连接NanoPi M2 / NanoPi 2 Fire

NanoPi M2和NanoPi 2 Fire的40 Pin引脚定义是一模一样的，所以它们操作Matrix配件的步骤是一样的，这里仅以NanoPi M2为例。
参考下图连接模块：

连接说明：

Matrix-Button	NanoPi M2
S	Pin7
V	Pin4
G	Pin6

4.4 连接NanoPC-T2

参考下图连接模块：
Matrix-Button_NanoPC-T2

连接说明：

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

5 编译运行测试程序

启动开发板并运行Debian系统，进入系统后克隆Matrix代码仓库：

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

克隆完成后会得到一个名为matrix的目录。

编译并安装Matrix：

$ cd matrix
$ make && make install

运行测试程序：

$ matrix-gpio_int

注意：此模块并不支持热插拔，启动系统前需要确保硬件连接正确。
运行效果如下：

Waiting event...
Device[0] value is 1

按下按键时会检测到事件。

6 代码说明

所有的开发板都共用一套Matrix代码，本模块的测试示例代码为matrix-gpio_int，内容如下:

int main(int argc, char ** argv)
{
    int i, board;
    int retSize = -1;
    char value[ARRAY_SIZE(dev)];
 
    if ((board = boardInit()) < 0)
        printf("Fail to init board\n");
 
    if (argc == 2) {
        dev[0].pin = atoi(argv[1]);
    }
    printf("Using GPIO_PIN(%d)\n", dev[0].pin);
    system("modprobe "DRIVER_MODULE);
    signal(SIGINT, intHandler);
    if (board == BOARD_NANOPI_T2)
        dev[0].pin = GPIO_PIN(15);
    if ((devFD =sensorInit(dev, ARRAY_SIZE(dev))) == -1) {
        printf("Fail to init sensor\n");
        return -1;
    }
    printf("Waiting event...\n");
    if ((retSize = sensorRead(devFD, value, ARRAY_SIZE(dev))) == -1) {
        printf("Fail to read sensors\n");
    }
    if (retSize > 0) {
        i = 0;
        for (i=0; i<retSize; i++) {
            printf("dev[%d] value: %d\n", i, value[i]);
        }
    }
    sensorDeinit(devFD);
    system("rmmod "DRIVER_MODULE);
    return 0;
}

API说明参考维基：Matrix API reference manual

8 Update Log

8.1 Feb-19-2016

• In section 4 added NanoPi 2 branch
• In section 5.2 added the driver and its source code's locations