Revision 0:8fe7d36af056, committed 2014-03-17

Comitter:

JENG

Date:

Mon Mar 17 12:35:48 2014 +0000

Commit message:

basic interface read dht11 show on clcd

Changed in this revision

diff -r 000000000000 -r 8fe7d36af056 main.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Mon Mar 17 12:35:48 2014 +0000
@@ -0,0 +1,221 @@
+
+#include "mbed.h"
+
+DigitalOut LCD_RS(D8);
+DigitalOut LCD_EN(D9);
+DigitalOut LCD_D4(D4);
+DigitalOut LCD_D5(D5);
+DigitalOut LCD_D6(D6);
+DigitalOut LCD_D7(D7);
+
+
+//########################################
+// LCD Library
+//########################################
+
+//send data to lcd
+void write_lcd(uint8_t d){
+
+    LCD_D4 = (d & 0x10)?1:0;
+    LCD_D5 = (d & 0x20)?1:0;
+    LCD_D6 = (d & 0x40)?1:0;
+    LCD_D7 = (d & 0x80)?1:0;
+
+    wait_us(2);
+    LCD_EN = 1;
+    wait_us(2);
+    LCD_EN = 0;
+
+}
+
+//lcd write byte
+void lcd_write_byte(uint8_t byte){
+
+    write_lcd(byte);
+    write_lcd(byte << 4);
+
+}
+
+//write command
+void lcd_putcmd(uint8_t c){
+
+    wait_ms(5);
+    lcd_write_byte(c);
+    
+}
+
+//write one char
+void lcd_putc(uint8_t d){
+
+    wait_ms(1);
+    LCD_RS = 1;
+    lcd_write_byte(d);
+    LCD_RS = 0;
+
+}
+
+
+
+//print string
+void lcd_puts(char * p){
+
+    while(* p)lcd_putc(* p++);
+
+}
+
+//lcd initial interface
+void lcd_initial(void){
+    
+    uint8_t x = 3;
+    
+    LCD_RS = 0;
+    LCD_EN = 0;
+
+    LCD_D4 = 0;
+    LCD_D5 = 0;
+    LCD_D6 = 0;
+    LCD_D7 = 0;
+
+    wait_ms(50);
+    
+    while(x--){
+        
+        write_lcd(0x30);
+        wait_ms(5);
+        
+    }
+
+    write_lcd(0x20);            //4bit interface
+
+    lcd_putcmd(0x28);           //function set
+    lcd_putcmd(0x08);           //display off
+    lcd_putcmd(0x01);           //display clear
+    lcd_putcmd(0x06);           //entry mode set
+    lcd_putcmd(0x0c);           //display on
+
+}
+//########################################
+// End of LCD Library
+//########################################
+
+#define DHTLIB_OK                0
+#define DHTLIB_ERROR_CHECKSUM   -1
+#define DHTLIB_ERROR_TIMEOUT    -2
+
+Timer tmr;
+
+DigitalInOut data_pin(A1);
+
+int humidity;
+int temperature;
+
+//########################################
+// DHT11 Library
+//########################################
+int dht_read(void){
+    
+    // BUFFER TO RECEIVE
+    uint8_t bits[5];
+    uint8_t cnt = 7;
+    uint8_t idx = 0;
+    
+    tmr.stop();
+    tmr.reset();
+
+    // EMPTY BUFFER
+    for(int i=0; i< 5; i++) bits[i] = 0;
+
+    // REQUEST SAMPLE
+    data_pin.output();
+    data_pin.write(0);
+    wait_ms(18);
+    data_pin.write(1);
+    wait_us(40);
+    data_pin.input();
+
+    // ACKNOWLEDGE or TIMEOUT
+    unsigned int loopCnt = 10000;
+    
+    while(!data_pin.read())if(!loopCnt--)return DHTLIB_ERROR_TIMEOUT;
+
+    loopCnt = 10000;
+    
+    while(data_pin.read())if(!loopCnt--)return DHTLIB_ERROR_TIMEOUT;
+
+    // READ OUTPUT - 40 BITS => 5 BYTES or TIMEOUT
+    for(int i=0; i<40; i++){
+        
+        loopCnt = 10000;
+        
+        while(!data_pin.read())if(loopCnt-- == 0)return DHTLIB_ERROR_TIMEOUT;
+
+        //unsigned long t = micros();
+        tmr.start();
+
+        loopCnt = 10000;
+        
+        while(data_pin.read())if(!loopCnt--)return DHTLIB_ERROR_TIMEOUT;
+
+        if(tmr.read_us() > 40) bits[idx] |= (1 << cnt);
+        
+        tmr.stop();
+        tmr.reset();
+        
+        if(cnt == 0){   // next byte?
+        
+            cnt = 7;    // restart at MSB
+            idx++;      // next byte!
+            
+        }else cnt--;
+        
+    }
+
+    // WRITE TO RIGHT VARS
+    // as bits[1] and bits[3] are allways zero they are omitted in formulas.
+    humidity    = bits[0]; 
+    temperature = bits[2]; 
+
+    uint8_t sum = bits[0] + bits[2];  
+
+    if(bits[4] != sum)return DHTLIB_ERROR_CHECKSUM;
+    
+    return DHTLIB_OK;
+    
+}
+
+char buffer[17];
+
+//########################################
+// End of DHT11 Library
+//########################################
+
+int main(void){
+    
+    lcd_initial();
+    
+    lcd_puts("=Nucleo - DHT11=");
+    
+    for(;;){
+        
+        if(!dht_read()){
+            
+            //sprintf(buffer, "Temp %2d C     ", temperature);
+            //lcd_putcmd(0x80);
+            //lcd_puts(buffer);
+            sprintf(buffer, "Hum %2d%%  Tmp %2dc", humidity, temperature);
+            lcd_putcmd(0xc0);
+            lcd_puts(buffer);
+            wait(0.5);
+            
+        }else{
+            
+            lcd_putcmd(0x80);
+            lcd_puts("Sensor Error !!!");
+            lcd_putcmd(0xc0);
+            lcd_puts("                ");
+            
+        }
+    
+    }
+    
+}

diff -r 000000000000 -r 8fe7d36af056 mbed.bld
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed.bld	Mon Mar 17 12:35:48 2014 +0000
@@ -0,0 +1,1 @@
+http://mbed.org/users/mbed_official/code/mbed/builds/8e73be2a2ac1
\ No newline at end of file