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--- products:sbc:common:applications:gpio:wiringpi [2022/06/30 00:04]
nick
+++ products:sbc:common:applications:gpio:wiringpi [2022/09/23 23:31]
frank [Using via C program]
@@ Line 1: / Line 1: @@
 ====== WiringPi ======
+===== Introduction =====
+This document mainly introduces the WiringPi. You will learn how to use the WiringPi to control the GPIO on the 40-Pin Header.
+<WRAP info >
+WiringPi is a C++ library for Raspberry Pi. With this library you can use many of the functionalities provided by the GPIO header: digital pins, SPI, I2C, UART, etc.
+</WRAP>
+===== WiringPi Instructions =====
+There are two methods here, via command line or C program.
+==== Get Pin Info ====
+Run ''gpio readall'', and it will print a table about the status of all GPIO pins.
+''GPIO'' –> GPIO native number \\
+''wPi'' –> WiringPi number \\
+''Mode'' –> GPIO Mode ,''ALT'' mean that this pin defined as a special function \\
+''V'' –> 1:HIGH 0:LOW \\
+''PU/PD'' –> ''PU'':pull up ''PD'':pull down ''DSBLD'':disabled ''PU''/''PD''
+==== Using via Command Line ====
+Here’s an example of controlling wpi number 1.
+  * Set GPIO mode to output
+```shell
+$ gpio mode 1 out
+```
+  * Set output low level
+```shell
+$ gpio write 1 0
+```
+  * Set output high level
+```shell
+$ gpio write 1 1
+```
+==== Using via C Program ====
+The test program changes the level value every 5S.
+```c wiringpi.c
+// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
+/*
+ * Copyright (c) 2022 Wesion Technology Co., Ltd.
+ *
+ * Author: Yan <yan-wyb@foxmail.com>
+ *
+ */
+#include <stdio.h>
+#include <wiringPi.h>
+const int gpio_pin = 1;
+int main()
+{
+    if(-1 == wiringPiSetup()){
+        printf("set up error");
+        exit(1);
+    }
+    pinMode(gpio_pin,OUTPUT);
+    while(1){
+        digitalWrite(gpio_pin,HIGH);
+        printf("wPi Pin %d now is GIGH\n",gpio_pin);
+        delay(5000);
+        digitalWrite(gpio_pin,LOW);
+        printf("wPi Pin %d now is LOW\n",gpio_pin);
+        delay(5000);
+    }
+    exit(0);
+}
+```
+Compile
+```shell
+$ gcc -o wiringpi wiringpi.c -lwiringPi -lpthread -lrt -lm -lcrypt
+```
+Run
+```shell
+sudo ./wiringpi
+wPi Pin 1 now is GIGH
+wPi Pin 1 now is LOW
+wPi Pin 1 now is GIGH
+wPi Pin 1 now is LOW
+```
+You can use ''gpio read 1'' to observe the pin level changes.
+==== Special Pin Functions ====
+Special pin functions of wiringpi include ''SPI'',''I2C'',''ADC'',''SoftPWM''.
+Please refer to the [[/products/sbc/common/applications/gpio/40pin-header|40-Pin Header]] for the corresponding physical pins.

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