Diff: main.cpp

Revision:

0:7b99226f4969

Child:

1:f77e8ece5ad9

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Thu Sep 28 03:31:46 2017 +0000
@@ -0,0 +1,241 @@
+#include "mbed.h"
+
+struct UART_buf
+{ 
+    uint8_t STA;
+    uint8_t MODE; 
+    uint8_t CMD;
+    uint8_t LEN;
+    uint8_t DATA[32];
+    uint8_t END; 
+     
+};
+ 
+
+#define DHTLIB_OK                0
+#define DHTLIB_ERROR_CHECKSUM   -1
+#define DHTLIB_ERROR_TIMEOUT    -2
+
+PinName pin_DHT11 = PA_15;
+
+Serial SerialUART(PA_2, PA_3);
+
+uint8_t Buffer[37];
+
+DigitalInOut data_pin(pin_DHT11);
+
+UART_buf RX_BUF;
+
+Timer tmr;
+Timer tmr1;
+
+int humi;
+int temp;
+
+void SerialUARTRX_ISR(void);
+void Timer_setting(uint8_t cmd, uint8_t value);
+void Sensor_Read(void);
+int dht_read(void);
+
+uint32_t T_period = 2000;
+uint32_t timer_check = 0;
+
+int main() {
+    
+    SerialUART.baud(115200);
+    
+    SerialUART.attach(&SerialUARTRX_ISR);
+    
+    Timer_setting(0x06, 2);
+    
+    while(1)
+    {
+        if((timer_check + T_period) < tmr1.read_ms())
+        {
+            Sensor_Read();
+            timer_check += T_period;
+        }
+    }
+}
+
+void SerialUARTRX_ISR(void)
+{
+    static uint8_t RX_count = 0, RX_Len = 32, RX_Status = 0;
+    uint8_t rx_da = SerialUART.getc();
+    switch(RX_Status)
+    {
+        case 0:
+            if(rx_da == 0x76)
+            {
+                RX_BUF.STA = rx_da;
+                RX_Status++;
+            }
+            break;
+        case 1:
+            RX_BUF.MODE = rx_da;
+            RX_Status++;
+            break;
+        case 2:
+            RX_BUF.CMD = rx_da;
+            RX_Status++;
+            break;
+        case 3:
+            RX_BUF.LEN = rx_da;
+            RX_Len = RX_BUF.LEN;
+            RX_Status++;
+            if(RX_Len == 0)
+                RX_Status++;
+            break;
+        case 4:
+            RX_BUF.DATA[RX_count] = rx_da;
+            RX_count++;
+            if(RX_count == RX_Len)
+            {
+                RX_Status++;
+                RX_count = 0;
+                RX_Len = 32;
+            }
+            break;
+        case 5:
+            if(rx_da == 0x3E)
+            {
+                RX_BUF.END = rx_da;
+                RX_Status = 0;
+                switch(RX_BUF.MODE)
+                {
+                    case 0x04:
+                        Timer_setting(RX_BUF.CMD, RX_BUF.DATA[0]);
+                        break;
+                }
+            }
+            break;
+    }
+}
+
+void Timer_setting(uint8_t cmd, uint8_t value)
+{
+    double Time_value = 0;
+    tmr1.stop();
+    tmr1.reset();
+    switch(cmd)
+    {
+        case 0x01:
+            Time_value = 30;
+            break;
+        case 0x02:
+            Time_value = 60;
+            break;
+        case 0x03:
+            Time_value = 120;
+            break;
+        case 0x04:
+            Time_value = 300;
+            break;
+        case 0x05:
+            Time_value = 600;
+            break;
+        case 0x06:
+            Time_value = value;
+            Time_value = 1.0/Time_value;
+            break;
+    }
+    tmr1.start();
+    timer_check = tmr.read_ms();
+    T_period = Time_value * 1000;
+}
+
+void Sensor_Read(void)
+{
+    Buffer[0] = 0x76;
+    Buffer[1] = 0x01;
+    Buffer[2] = 0x05;
+    Buffer[3] = 0x02;
+    if(dht_read() == 0)
+    {
+        Buffer[4] = temp;
+        Buffer[5] = humi;
+    }
+    else
+    {
+        Buffer[4] = 0;
+        Buffer[5] = 0;
+    }
+    Buffer[6] = 0x3E;
+    for(int i=0; i<7; i++)
+        SerialUART.putc(Buffer[i]);
+}
+
+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(10);
+    data_pin.input();
+    wait_us(40);
+
+    // ACKNOWLEDGE or TIMEOUT
+    unsigned long loopCnt = 10000;
+    
+    while(data_pin.read() == 0)if(!loopCnt--)return DHTLIB_ERROR_TIMEOUT;
+ 
+    loopCnt = 10000;
+    
+    while(data_pin.read() == 1)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() == 0)if(loopCnt-- == 0)return DHTLIB_ERROR_TIMEOUT;
+
+        //unsigned long t = micros();
+        //time_count = tmr.read_us();
+        
+        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.
+    humi = bits[0]; 
+    temp = bits[2]; 
+
+    uint8_t sum = bits[0] + bits[1] + bits[2] + bits[3];
+    
+    if(bits[4] != sum){return DHTLIB_ERROR_CHECKSUM;}
+    
+    return DHTLIB_OK;
+    
+}
\ No newline at end of file