在上文中,按照guide, 在樹莓派目標板上install bcm2835.
因爲bcm2835是用戶空間應用,所以可以在宿主機上交叉編譯,生成binary後在樹莓派執行
按照guide:
- Installation
This library consists of a single non-shared library and header file, which will be installed in the usual places by make install
這裏我們不需要安裝,只要make生成.a庫就可以。
交叉編譯:
./configure -host=arm CC=arm-linux-gnueabihf-gcc-4.9.3 ar=arm-linux-gnueabihf-ar
make
在make時出現錯誤
Bcm2835-1.45$ make
CDPATH="${ZSH_VERSION+.}:" && cd . && aclocal-1.13 -I m4
/bin/bash: aclocal-1.13: command not found
Makefile:327: recipe for target 'aclocal.m4' failed
make: *** [aclocal.m4] Error 127
解決:
1. sudo apt-get install automake
2. sudo autoreconf -ivf
然後make,無報錯
在src下生成了.a文件
~/Raspberry/bcm2835-1.56/src$ ls
bcm2835.c bcm2835.o Makefile Makefile.in
bcm2835.h libbcm2835.a Makefile.am test.c
將bcm2835.a 以及頭文件 bcm2835.h, copy到led.c目錄下,編譯LED測試文件
led.c 如下
#include <bcm2835.h>
#define PIN 26
int main(int argc, char **argv)
{
if (!bcm2835_init())return 1;
bcm2835_gpio_fsel(PIN, BCM2835_GPIO_FSEL_OUTP);
while (1)
{
bcm2835_gpio_write(PIN, HIGH);
bcm2835_delay(500);
bcm2835_gpio_write(PIN, LOW);
bcm2835_delay(500);
}
bcm2835_close();
return 0;
}
makefile
CC = arm-linux-gnueabihf-gcc-4.9.3
LD = arm-linux-gnueabihf-ld
led:led.c
$(CC) -Wall -I./ led.c -o led -L./lib -lbcm2835
clean:
rm led
將生成的led binary文件copy到樹莓派執行, LED閃爍
http://www.airspayce.com/mikem/bcm2835/