MicroComputerSystem

중앙대학교 창의ICT공과대학 전자전기공학부 - 마이크로컴퓨터시스템

ARM MircroProcesser Core Assembly Language with Raspi 3

Peripheral Device Control using Linux Kernel System Call with Virtual Memory Mapping
BumSoo Kim*
In 2021 MicroComputerSystem Lecture, CAU (* CAU A&T)

ARM Programming

Environment

• OS : Raspbian (Raspberry Pi 3)
• Compiler : gcc (Not Keil)
• Editor : nano
• language : ARM Assembly

	.data	@data area
string:	.asciz "Hello world\n"

	.text	@code area
	.global main
	
main:
	push {lr}	@push {r14}
	ldr r0, =string	@parameter
	bl printf
	pop {pc}	@pop {r15}
	.end	@end

Getting Started

make directory and source file

pwd
mkdir src
nano example.s

assemble source code and run

gcc example.s -o example
./exmaple

---

GPIO Programming

Environment

• OS : Raspbian (Raspberry Pi 3)
• Compiler : gcc (Not Keil)
• Editor : nano
• language : C

#include <stdio.h>
#include <wiringPi.h>

#define LED 18

void main(void){
	wiringPiSetupGpio();
	pinMode(LED, OUTPUT);
	
	for(;;){
		digitalWrite(LED, 1);
		delay(500);
		digitalWrite(LED, 0);
		delay(500);
	}
}

gpio -g mode [N] out
gpio -g write [N] 1
gpio -g write [N] 0

Getting Started

(High Level) Peripheral Device Controll with wiringPi

install WiringPi

sudo apt-get install git-core
git clone http://github.com/WiringPi/WiringPi
cd WiringPi
./build

compile c source code and run

nano example.c
gcc -o example example.c -lwiringPi
./example

(Low Level) Peripheral Device Controll with mmap

compile custom wiringPi to library file

nano gpmmlib.c
gcc -I./include -c gpmmlib.c
ar r libgpmm.a gpmmlib.o
ranlib libgpmm.a
mkdir lib
mv libgpmm.a ./lib

compile c source with custom library

nano example.c
gcc -I./include -L./lib -o example example.c -lgpmm
sudo ./example