I have nothing to do, bought a Raspberry Pi 3B on the second-hand market and turned on the first LED
Raspberry Pi 3B+ lights up the first LED, beginners can make a comparison
Node.js and rpio have been installed on the Raspberry Pi in the previous article. The next thing to do is to use rpio to light up the first LED.
1. Raspberry Pi pin diagram
In this picture, you can see that there is a row of pins on it. This is the GPIO and some power pins exposed by the Raspberry Pi. So what exactly does each pin header do? In fact, we don't know what this board is when we look at it.
execute gpio readall
+-----+-----+---------+------+---+---Pi 3B+-+---+------+---------+-----+-----+
| BCM | wPi | Name | Mode | V | Physical | V | Mode | Name | wPi | BCM |
+-----+-----+---------+------+---+----++----+---+------+---------+-----+-----+
| | | 3.3v | | | 1 || 2 | | | 5v | | |
| 2 | 8 | SDA.1 | ALT0 | 1 | 3 || 4 | | | 5v | | |
| 3 | 9 | SCL.1 | ALT0 | 1 | 5 || 6 | | | 0v | | |
| 4 | 7 | GPIO. 7 | IN | 0 | 7 || 8 | 1 | ALT5 | TxD | 15 | 14 |
| | | 0v | | | 9 || 10 | 1 | ALT5 | RxD | 16 | 15 |
| 17 | 0 | GPIO. 0 | IN | 0 | 11 || 12 | 0 | IN | GPIO. 1 | 1 | 18 |
| 27 | 2 | GPIO. 2 | IN | 0 | 13 || 14 | | | 0v | | |
| 22 | 3 | GPIO. 3 | IN | 0 | 15 || 16 | 0 | IN | GPIO. 4 | 4 | 23 |
| | | 3.3v | | | 17 || 18 | 0 | IN | GPIO. 5 | 5 | 24 |
| 10 | 12 | MOSI | ALT0 | 0 | 19 || 20 | | | 0v | | |
| 9 | 13 | MISO | ALT0 | 0 | 21 || 22 | 0 | IN | GPIO. 6 | 6 | 25 |
| 11 | 14 | SCLK | ALT0 | 0 | 23 || 24 | 1 | OUT | CE0 | 10 | 8 |
| | | 0v | | | 25 || 26 | 1 | OUT | CE1 | 11 | 7 |
| 0 | 30 | SDA.0 | IN | 1 | 27 || 28 | 1 | IN | SCL.0 | 31 | 1 |
| 5 | 21 | GPIO.21 | IN | 1 | 29 || 30 | | | 0v | | |
| 6 | 22 | GPIO.22 | IN | 1 | 31 || 32 | 0 | IN | GPIO.26 | 26 | 12 |
| 13 | 23 | GPIO.23 | IN | 0 | 33 || 34 | | | 0v | | |
| 19 | 24 | GPIO.24 | IN | 0 | 35 || 36 | 0 | IN | GPIO.27 | 27 | 16 |
| 26 | 25 | GPIO.25 | IN | 0 | 37 || 38 | 0 | IN | GPIO.28 | 28 | 20 |
| | | 0v | | | 39 || 40 | 0 | IN | GPIO.29 | 29 | 21 |
+-----+-----+---------+------+---+----++----+---+------+---------+-----+-----+
| BCM | wPi | Name | Mode | V | Physical | V | Mode | Name | wPi | BCM |
+-----+-----+---------+------+---+---Pi 3B+-+---+------+---------+-----+-----+
Through this command, you can see the specific function of each pin header. Following the pin headers on the board above, the first one in the upper right corner is Pin 1 corresponding to Physical. Since I use the rpio library, I actually need to look at the two columns Name and Physical.
In fact, the best picture is this one:
But in the next experiment we only need to use a GND pin and a GPIO.0 pin, which are the physical pins 9 and 11 of the physical pins on the board.
2. Circuit diagram for lighting up the LED
serial number
Raspberry Pi pins
LED pins
1
9
LED negative
2
11
LED positive
3. The procedure to light up the LED
a. Create a new node_led.js file: touch node_led.js
b. Write the following code
letrpio=require('rpio');//Introduce the rpio library letled_pin=11;//Define the pin number rpio.open(led_pin,rpio.OUTPUT,rpio.LOW);//Set the output to a low level initially functionblink(){
while(1){
rpio.write(led_pin,rpio.HIGH);//output high level rpio.msleep(500);//delay 500msrpio.write(led_pin,rpio.LOW);//output low level rpio.msleep (500);//Delay 500ms}}blink();//Execute this method
c. Execute this program: node node_led.js
d. The actual LED light starts blinking.