### Project 13 8*16 dot matrix-turn on one line

**1.Project instruction** 

In previous program, we light up a coordinate point. In this project, we will light up a row of LEDs.

**2.Project Principle**

![](media/31.png)

To light a row of LEDs, we need to make use of function matrix.drawLine. Lighting up the start and terminal point on a row of LEDs indicates all LEDs on this row are on, therefore, we need to decide the start and terminal point of this row of LEDs.

![](media/32.png)

Seeing from the above picture, the start point locates (5,0) and the end one is（5,15). Next, we place the value in the below code.

**3.Project circuit**

![](media/33.png)

**4.Project code**

```c
/*
keyestudio Max Development Board
Project 13
 8*16 dot matrix-turn on one line
http://www.keyestudio.com
*/
#include <Wire.h>
#include "Keyestudio_LEDBackpack.h"
#include "Keyestudio_GFX.h"
Keyestudio_8x16matrix matrix = Keyestudio_8x16matrix();

void setup() 
{
 matrix.begin(0x70);  // pass in the address
}

void loop() 
{
 matrix.clear();
 matrix.drawLine(5,0, 5,15, LED_ON);
 matrix.writeDisplay();  // write the changes we just made to the display
}
```