Matrix - LED
Contents
Introduction
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
- 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.
Download Matrix Source Code
All the matrix modules' code samples are open source. They are maintained on GitHub - https://github.com/friendlyarm/matrix.git
Each branch in this hub contains the matrix modules' code samples for a board that the matrix modules can work with.
- The nanopi branch contains the matrix modules' code samples for the NanoPi
- The tiny4412 branch contains the matrix modules' code samples for the Tiny4412
- The raspberrypi branch contains the matrix modules' code samples for the RaspberryPi
Please follow the steps below to get the source code:
Install the git utility on a PC running Ubuntu14.04
$ sudo apt-get install git
Clone the matrix code from GitHub
$ git clone https://github.com/friendlyarm/matrix.git
If this is successful a "matrix" directory will be generated, which will contain all the matrix modules' code samples.
Connect to NanoPi
Preparations
Please install a Debian on a NanoPi and an appropriate cross compiler on a PC. Please refer to wiki:NanoPi
Compile a NanoPi kernel. Note: please use the kernel's source code from the nanopi-v4.1.y-matrix branch.
$ git clone https://github.com/friendlyarm/linux-4.x.y.git
$ cd linux-4.x.y
$ git checkout nanopi-v4.1.y-matrix
$ make nanopi_defconfig
$ touch .scmversion
$ make
Hardware Connection
Please refer to the following connection diagram to connect the Matrix-LED to the NanoPi
Connection Details:
Matrix-LED | NanoPi |
S | Pin7 |
V | Pin4 |
G | Pin6 |
Compile Test Program
Please login the matrix hub and enter the nanopi branch
$ cd matrix
$ git checkout nanopi
Compile the matrix code
$ make CROSS_COMPILE=arm-linux- clean
$ make CROSS_COMPILE=arm-linux-
$ make CROSS_COMPILE=arm-linux- install
Note: please make sure to install the cross compiler "arm-linux-gcc-4.4.3" on your PC, which is used to compile files for the NanoPi-Debian.
Generated library files are under the "install/lib" directory. Applications are under the "install/usr/bin" directory. The test program for the "Matrix-LED" module is "matrix-led".
Run Test Program
Please copy the library files and test program to the NanoPi
$ cp install/usr/bin/* nanopi_rootfs/usr/bin/
$ cp install/lib/* nanopi_rootfs/lib/ -d
Power on the NanoPi and run the following command in Debian's terminal
$ matrix-led
Code Sample
int main(int argc, char ** argv)
{
int ledPin = GPIO_PIN1;
int i = 0;
int ret = -1;
if ((ret = exportGPIOPin(ledPin)) == -1) {
printf("exportGPIOPin(%d) failed\n", ledPin);
}
if ((ret = setGPIODirection(ledPin, GPIO_OUT)) == -1) {
printf("setGPIODirection(%d) failed\n", ledPin);
}
for (i = 0; i < LED_BLINK_TIMES; i++) {
if (i % 2) {
ret = setGPIOValue(ledPin, GPIO_HIGH);
} else {
ret = setGPIOValue(ledPin, GPIO_LOW);
}
if (ret == -1) {
printf("setGPIOValue(%d) failed\n", ledPin);
}
printf("LED blinking times %d\n", i);
sleep(1);
}
unexportGPIOPin(ledPin);
return 0;
}
Connect to Tiny4412
Preparations
Please refer to the Tiny4412's user's manual to install a UbuntuCore on the Tiny4412 and install an appropriate cross compiler on a PC.
Note: only the Tiny4412SDK-1506 carrier board can work with this module.
Hardware Connection
Please refer to the following diagram to connect the Matrix-LED to the Tiny4412
Connection Details:
Matrix-LED | Tiny4412 |
S | GPIO1 S |
V | GPIO1 5V |
G | GPIO1 GND |
Compile Test Program
Please login the Matrix hub and enter the matrix-tiny4412 branch
$ cd matrix
$ git checkout tiny4412
Compile the matrix code
$ make CROSS_COMPILE=arm-linux-gnueabihf- clean
$ make CROSS_COMPILE=arm-linux-gnueabihf-
$ make CROSS_COMPILE=arm-linux-gnueabihf- install
Note: please make sure to install the cross compiler "arm-linux-gnueabihf-gcc-4.7.3" on your PC, which is used to compile files for the Tiny4412-UbuntuCore.
Generated library files are under the "install/lib" directory. Applications are under the "install/usr/bin" directory. The test program for the "Matrix-LED" module is "matrix-led".
Run Test Program
Please copy the library files and test program to the Tiny4412
$ cp install/usr/bin/* tiny4412_rootfs/usr/bin/
$ cp install/lib/* tiny4412_rootfs/lib/ -d
Power on the Tiny4412 and run the following command in UbuntuCore's terminal
$ matrix-led
Code Sample
int main(int argc, char ** argv)
{
int ledPin = GPIO_PIN1;
int i = 0;
int ret = -1;
if ((ret = exportGPIOPin(ledPin)) == -1) {
printf("exportGPIOPin(%d) failed\n", ledPin);
}
if ((ret = setGPIODirection(ledPin, GPIO_OUT)) == -1) {
printf("setGPIODirection(%d) failed\n", ledPin);
}
for (i = 0; i < LED_BLINK_TIMES; i++) {
if (i % 2) {
ret = setGPIOValue(ledPin, GPIO_HIGH);
} else {
ret = setGPIOValue(ledPin, GPIO_LOW);
}
if (ret == -1) {
printf("setGPIOValue(%d) failed\n", ledPin);
}
printf("LED blinking times %d\n", i);
sleep(1);
}
unexportGPIOPin(ledPin);
return 0;
}