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 지난번 올렸던 C언어로 라즈베리파이 3의 LED제어 했던 것에 이어서 글을 올립니다.









 C언어로 Raspberry Pi 3의 GPIO 레지스터 접근하여 LED켜보기




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 이번엔 버튼을 하나 추가하여 버튼을 누른 동안에는 LED가 켜지고 손을 떼면 LED가 꺼지게 됩니다.. 





 GPIO18번에 LED가 연결되어 있고 아래 사진처럼 GPIO17번에는 버튼을 연결하고 풀다운저항을 추가했습니다. 




<figure><img data-lazy-fallback="1" data-attachment-id="6132" data-permalink="https://webnautes.blog/6131/word-image-6131-1/" data-orig-file="https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-1.png?fit=172%2C261&amp;ssl=1" data-orig-size="172,261" data-comments-opened="1" data-image-meta="{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}" data-image-title="word-image-6131-1" data-image-description="" data-image-caption="" data-medium-file="https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-1.png?fit=172%2C261&amp;ssl=1" data-large-file="https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-1.png?fit=172%2C261&amp;ssl=1" decoding="async" width="172" height="261" src="https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-1.png?resize=172%2C261&amp;ssl=1" alt="" data-recalc-dims="1" data-old-src="https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-1.png?resize=172%2C261&amp;is-pending-load=1#038;ssl=1"></figure>



<figure><img data-lazy-fallback="1" data-attachment-id="6133" data-permalink="https://webnautes.blog/6131/word-image-6131-2/" data-orig-file="https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-2.jpeg?fit=1307%2C903&amp;ssl=1" data-orig-size="1307,903" data-comments-opened="1" data-image-meta="{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}" data-image-title="word-image-6131-2" data-image-description="" data-image-caption="" data-medium-file="https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-2.jpeg?fit=300%2C207&amp;ssl=1" data-large-file="https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-2.jpeg?fit=1024%2C707&amp;ssl=1" decoding="async" fetchpriority="high" width="1200" height="829" src="https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-2.jpeg?resize=1200%2C829&amp;ssl=1" alt="" sizes="(max-width: 1200px) 100vw, 1200px" data-recalc-dims="1" data-old-src="https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-2.jpeg?resize=1200%2C829&amp;is-pending-load=1#038;ssl=1" data-lazy-srcset="https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-2.jpeg?w=1307&amp;ssl=1 1307w, https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-2.jpeg?resize=300%2C207&amp;ssl=1 300w, https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-2.jpeg?resize=1024%2C707&amp;ssl=1 1024w, https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-2.jpeg?resize=768%2C531&amp;ssl=1 768w, https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-2.jpeg?resize=1200%2C829&amp;ssl=1 1200w"></figure>



<figure><img data-lazy-fallback="1" data-attachment-id="6134" data-permalink="https://webnautes.blog/6131/word-image-6131-3/" data-orig-file="https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-3.png?fit=1458%2C1538&amp;ssl=1" data-orig-size="1458,1538" data-comments-opened="1" data-image-meta="{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}" data-image-title="word-image-6131-3" data-image-description="" data-image-caption="" data-medium-file="https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-3.png?fit=284%2C300&amp;ssl=1" data-large-file="https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-3.png?fit=971%2C1024&amp;ssl=1" decoding="async" width="1200" height="1266" src="https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-3.png?resize=1200%2C1266&amp;ssl=1" alt="" sizes="(max-width: 1200px) 100vw, 1200px" data-recalc-dims="1" data-old-src="https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-3.png?resize=1200%2C1266&amp;is-pending-load=1#038;ssl=1" data-lazy-srcset="https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-3.png?w=1458&amp;ssl=1 1458w, https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-3.png?resize=284%2C300&amp;ssl=1 284w, https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-3.png?resize=971%2C1024&amp;ssl=1 971w, https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-3.png?resize=768%2C810&amp;ssl=1 768w, https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-3.png?resize=1456%2C1536&amp;ssl=1 1456w, https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-3.png?resize=1200%2C1266&amp;ssl=1 1200w"></figure>








 GPFSEL1레지스터를 접근하여 핀을 입력으로 쓸지 출력으로 쓸지 결정해주어야 합니다. 





 입력의 경우에 디폴드값이 000이므로 아래 FSEL17는 건드릴 필요가 없습니다. 





 LED를 켜야하므로 FSEL18은 001로 해주어 출력으로 해주어야 합니다. 




<figure><img data-lazy-fallback="1" data-attachment-id="6135" data-permalink="https://webnautes.blog/6131/word-image-6131-4/" data-orig-file="https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-4.png?fit=561%2C436&amp;ssl=1" data-orig-size="561,436" data-comments-opened="1" data-image-meta="{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}" data-image-title="word-image-6131-4" data-image-description="" data-image-caption="" data-medium-file="https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-4.png?fit=300%2C233&amp;ssl=1" data-large-file="https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-4.png?fit=561%2C436&amp;ssl=1" decoding="async" loading="lazy" width="561" height="436" src="https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-4.png?resize=561%2C436&amp;ssl=1" alt="" sizes="(max-width: 561px) 100vw, 561px" data-recalc-dims="1" data-old-src="https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-4.png?resize=561%2C436&amp;is-pending-load=1#038;ssl=1" data-lazy-srcset="https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-4.png?w=561&amp;ssl=1 561w, https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-4.png?resize=300%2C233&amp;ssl=1 300w"></figure>








 핀으로부터 입력을 읽어오는 레지스터의 오프셋은 0034입니다.





 따라서 이 레지스터의 위치는 GPIO레지스터 시작위치 + 0034가 되겠죠.





 하지만 mmap할때 레지스터의 시작위치부터 0이 되버리므로 0034만 알고 있으면 됩니다. 




<figure><img data-lazy-fallback="1" data-attachment-id="6136" data-permalink="https://webnautes.blog/6131/word-image-6131-5/" data-orig-file="https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-5.png?fit=700%2C68&amp;ssl=1" data-orig-size="700,68" data-comments-opened="1" data-image-meta="{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}" data-image-title="word-image-6131-5" data-image-description="" data-image-caption="" data-medium-file="https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-5.png?fit=300%2C29&amp;ssl=1" data-large-file="https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-5.png?fit=700%2C68&amp;ssl=1" decoding="async" loading="lazy" width="700" height="68" src="https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-5.png?resize=700%2C68&amp;ssl=1" alt="" sizes="(max-width: 700px) 100vw, 700px" data-recalc-dims="1" data-old-src="https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-5.png?resize=700%2C68&amp;is-pending-load=1#038;ssl=1" data-lazy-srcset="https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-5.png?w=700&amp;ssl=1 700w, https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-5.png?resize=300%2C29&amp;ssl=1 300w"></figure>








 GPIO17번으로 부터 값을 읽어 올거기 때문에 17번 비트의 값이 1인지 여부를 체크하면 됩니다.





 버튼을 누르게 되면 5V가 핀으로 입력되기 때문에 해당 핀에 대응되는 비트는 1로 바뀌기 때문입니다. 




<figure><img data-lazy-fallback="1" data-attachment-id="6137" data-permalink="https://webnautes.blog/6131/word-image-6131-6/" data-orig-file="https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-6.png?fit=700%2C230&amp;ssl=1" data-orig-size="700,230" data-comments-opened="1" data-image-meta="{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}" data-image-title="word-image-6131-6" data-image-description="" data-image-caption="" data-medium-file="https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-6.png?fit=300%2C99&amp;ssl=1" data-large-file="https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-6.png?fit=700%2C230&amp;ssl=1" decoding="async" loading="lazy" width="700" height="230" src="https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-6.png?resize=700%2C230&amp;ssl=1" alt="" sizes="(max-width: 700px) 100vw, 700px" data-recalc-dims="1" data-old-src="https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-6.png?resize=700%2C230&amp;is-pending-load=1#038;ssl=1" data-lazy-srcset="https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-6.png?w=700&amp;ssl=1 700w, https://i0.wp.com/webnautes.blog/wp-content/uploads/2023/09/word-image-6131-6.png?resize=300%2C99&amp;ssl=1 300w"></figure>








 실행시켜보면 버튼 누를때 마다 LED가 켜집니다. 





 pi@raspberrypi:~ $ gcc button.c -o button





 pi@raspberrypi:~ $ sudo ./button









 아래는 전체 소스 코드 입니다.




<pre><code>#include &lt;stdlib.h&gt; 
#include &lt;stdio.h&gt; 
#include &lt;sys/types.h&gt; 
#include &lt;sys/stat.h&gt; 
#include &lt;fcntl.h&gt; 
#include &lt;sys/mman.h&gt; 
 
 
#define GPIO_BASE 0x3F200000 
#define GPFSEL1 0x04 
#define GPLEV0 0x34 
#define GPSET0 0x1C 
#define GPCLR0 0x28 
 
 
int main() 
{ 
 int fd = open( "/dev/mem", O_RDWR|O_SYNC ); 
 if ( fd &lt; 0 ){ 
 printf( "can't open /dev/mem \n" ); 
 exit(-1); 
 } 
 
 
 char *gpio_memory_map = (char *)mmap( 0, 4096, PROT_READ|PROT_WRITE, 
 MAP_SHARED, fd, GPIO_BASE ); 
 
 if ( gpio_memory_map == MAP_FAILED ) 
 { 
 printf( " Error : mmap \n" ); 
 exit(-1); 
 } 
 
 
 volatile unsigned int* gpio = (volatile unsigned int*)gpio_memory_map; 
 
 gpio[GPFSEL1/4] |= (1&lt;&lt;24); 
 
 while(1) 
 { 
 int input = gpio[GPLEV0/4] &amp; (0x01&lt;&lt;17); 
 
 if ( input &gt; 0 ) 
 gpio[GPSET0/4] |= (1&lt;&lt;18); 
 else 
 gpio[GPCLR0/4] |= (1&lt;&lt;18); 
 } 
 
 munmap( gpio_memory_map, 4096); 
 
 return 0; 
} </code></pre>








 마지막 업데이트 2019. 2. 18






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멈춤보단 천천히라도

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지난번 올렸던 C언어로 라즈베리파이 3의 LED제어 했던 것에 이어서 글을 올립니다. C언어로 Raspberry Pi 3의 GPIO 레지스터 접근하여 LED켜보기 이번엔 버튼을 하나 추가하여 버튼을 누른 동안에는 LED가 켜지고 손을 떼면 LED가 꺼지게 됩니다.. GPIO18번에 LED가 연결되어 있고 아래 사진처럼 GPIO17번에는 버튼을 연결하고 풀다운저항을 추가했습니다. GPFSEL1레지스터를 접근하여 핀을 입력으로 쓸지 출력으로 쓸지 결정해주어야 합니다. 입력의 경우에… 더 보기 »C언어로 Raspberry Pi 3의 GPIO 레지스터 접근하여 버튼값 읽어오기
The post C언어로 Raspberry Pi 3의 GPIO 레지스터 접근하여 버튼값 읽어오기 first appeared on 멈춤보단 천천히라도.

C언어로 Raspberry Pi 3의 GPIO 레지스터 접근하여 버튼값 읽어오기

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