Cubieboard1显示DS18B20温度信息到LED
Cubieboard1的内核已经支持w1温度传感器DS18B20 (依赖的内核选项和模块包括dallas's 1-wire support, gpio_sunxi, w1_sunxi, w1_gpio, w1_slave_therm )。 下图的DIY是在8位8段LED显示模块上同时显示当前时间和气温的实验。
jarry大侠在很久前的帖子(http://forum.cubietech.com/forum.php?mod=viewthread&tid=474)中介绍了DS18B20在cubieboard1上的使用，现在已经不需要打补丁或者另外编译内核模块了。只要按内核配置的说明改好script.bin即可：
本例中的script.fex相关设置如下：
[gpio_para]
gpio_used = 1
gpio_num = 31
...
gpio_pin_28 = port:PB10<0><default><default><0>
gpio_pin_29 = port:PB11<1><default><default><default>
gpio_pin_30 = port:PB13<1><default><default><default>
gpio_pin_31 = port:PH07<1><default><default><default>
[w1_para]
gpio = 28
[color=rgb(46, 166, 255) !important] 复制代码
最后是本例的C代码
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <signal.h>
#include <pthread.h>
#include "gpio_lib.h"
#define LSBFIRST 0
#define MSBFIRST 1
#define DISPBUF_LEN 8
typedef unsigned char byte;
// w1-thermal(DS18B20) device file, change it in your case.
const char* DS18B20_DEVICE="/sys/bus/w1/devices/28-000004f0230d/w1_slave";
/*
* 74HC595 relative stuff
*/
// Cubieboard pin connected to ST_CP of 74HC595 (RCK)
unsigned int latchPin = SUNXI_GPB(11);
// Cubieboard pin connected to SH_CP of 74HC595 (SCK)
unsigned int clockPin = SUNXI_GPB(13);
// Cubieboard pin connected to DS of 74HC595 (DIN)
unsigned int dataPin = SUNXI_GPH(7);
/*
* Display relative stuff
*/
// Digits: "0,1,2,....,9" for common anode 8-segment-LED
unsigned int digit_tab[] = { 0xc0, 0xf9, 0xa4, 0xb0, 0x99, 0x92,
0x82, 0xf8, 0x80, 0x90};
// Digits with a 'dot' at the right-bottom corner
unsigned int digitdot_tab[] = { 0xc0&0x7f, 0xf9&0x7f, 0xa4&0x7f,
0xb0&0x7f, 0x99&0x7f, 0x92&0x7f, 0x82&0x7f,
0xf8&0x7f, 0x80&0x7f, 0x90&0x7f};
// Symbols: 'clear', 'dot', '-'
unsigned int symbol_tab[]={ 0xff, 0x7f, 0xbf};
// LED display buffer
static char dispbuf[DISPBUF_LEN];
/**
* Set Cubieboard's GPIO port-D pin I/O mode: INPUT/OUTPUT
*/
void pinMode(unsigned int pin, unsigned int io_mode)
{
if (SETUP_OK != sunxi_gpio_set_cfgpin(pin, io_mode))
{
printf("Failed to config GPIO pin\n");
}
}
/**
* Set Cubieboard's GPIO port-D pin value(LOW/HIGH)
*/
void digitalWrite(int pin, int hl)
{
if (sunxi_gpio_output(pin, hl))
{
printf("Failed to set GPIO pin value\n");
}
}
/**
* Arduino shiftOut:
* https://github.com/arduino/Ardui ... uino/wiring_shift.c
*/
void shiftOut(unsigned int dataPin, unsigned int clockPin, int bitOrder, byte val)
{
byte i;
for (i = 0; i < 8; i++)
{
if (bitOrder == LSBFIRST)
digitalWrite(dataPin, ! !(val & (1 << i)));
else
digitalWrite(dataPin, ! !(val & (1 << (7 - i))));
digitalWrite(clockPin, HIGH);
digitalWrite(clockPin, LOW);
}
}
/**
* Initialize the GPIO & relative pins
*/
void init_gpio()
{
if (SETUP_OK != sunxi_gpio_init())
{
printf("Failed to initialize GPIO\n");
}
pinMode(latchPin, OUTPUT);
pinMode(clockPin, OUTPUT);
pinMode(dataPin, OUTPUT);
}
/**
* Get current temperature from the w1-thermal device
*/
void get_temperature(char* tempbuf, int len)
{
FILE* fp=fopen(DS18B20_DEVICE,"r");
char* line=NULL;
char* temperature_tok=NULL;
int temperature=0;
int n;
if(!fp){
fprintf(stderr,"Failed to open device(%s) file!\n", DS18B20_DEVICE);
return;
}
// skip the first line
getline(&line, &n, fp);
free(line);
line=NULL;
// get the temperature line
getline(&line, &n, fp);
strtok(line,"=");
temperature_tok=strtok(NULL,"\n");
strncpy(tempbuf, temperature_tok, len);
free(line);
fclose(fp);
}
/**
* Thread of filling the time infomation into display buffer
*/
void* time_to_dispbuf()
{
time_t timep;
struct tm *p;
char timebuf[4];
int interval=1; // in seconds
while(1){
// get localtime
time(&timep);
p = localtime(&timep);
sprintf(timebuf, "%02d%02d", p->tm_hour, p->tm_min);
dispbuf[0]=digit_tab[timebuf[0] - '0'];
dispbuf[1]=digitdot_tab[timebuf[1] - '0'];
dispbuf[2]=digit_tab[timebuf[2] - '0'];
dispbuf[3]=digit_tab[timebuf[3] - '0'];
dispbuf[4]=symbol_tab[2]; // '-'
sleep(interval);
}
}
/**
* Thread of filling the temperature into display buffer
*/
void* temp_to_dispbuf()
{
char tempbuf[3];
int interval=5; // in seconds;
while(1){
get_temperature(tempbuf, sizeof tempbuf);
dispbuf[5]=digit_tab[tempbuf[0]-'0'];
dispbuf[6]=digitdot_tab[tempbuf[1]-'0'];
dispbuf[7]=digit_tab[tempbuf[2]-'0'];
sleep(interval);
}
}
int main(int argc, char **argv)
{
pthread_t get_time_thread, get_temp_thread;
void * thread_ret;
init_gpio();
pthread_create( &get_time_thread, NULL, time_to_dispbuf, NULL);
pthread_create( &get_temp_thread, NULL, temp_to_dispbuf, NULL);
while (1)
{
int i;
for(i=0;i<DISPBUF_LEN;i++){
digitalWrite(latchPin, 0);
shiftOut(dataPin, clockPin, MSBFIRST, 1<<i);
shiftOut(dataPin, clockPin, MSBFIRST, dispbuf);
digitalWrite(latchPin, 1);
usleep(2000);
}
}
pthread_join(get_time_thread,&thread_ret);
pthread_join(get_temp_thread,&thread_ret);
return 0;
}
原文作者：soloforce
原文链接：http://forum.cubietech.com/forum ... 1545&extra=page%3D1