| HOW TO READ DHT22 WITH C1000?? [message #1775646] |
Thu, 02 November 2017 10:46  |
Eclipse User |
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Why it didn't show any value or reading from the sensor (dht22)?
How to read the raw value from digital pin?
#include "qm_gpio.h" //Calling QMSI GPIO API
#include "clk.h"
#include "qm_pinmux.h"
#include "qm_pin_functions.h"
#define PIN_DHT22 21
#define LED_PIN_ID (QM_PIN_ID_55)
#define PIN_MUX_FN (QM_PIN_55_FN_GPIO_21)
//static qm_gpio_state_t {QM_GPIO_HIGH};
uint32_t expectPulse(_Bool level) /*function to read DHT11 pulse*/
{
uint32_t count = 0;
while (qm_gpio_read_pin(QM_GPIO_0, PIN_DHT22, QM_GPIO_LOW) == level)
{
if (count++ >= 100000)
{ /* 1 millisecond to read DHT11 pulse */
return 0; /* Exceeded timeout, fail. */
}
}
return count;
}
static void pin_mux_setup(void)
{
qm_pmux_select(LED_PIN_ID, PIN_MUX_FN);
}
int main()
{
qm_gpio_port_config_t cfg;
pin_mux_setup();
uint32_t cycles[80], i; /* same cycle number as in the DHT11 library */
uint8_t data[5];
/* Reset 40 bits of received data to zero. */
data[0] += data[1] += data[2] += data[3] += data[4] = 0;
QM_PUTS("DHT22 example");
while(1)
{
// Act like Arduino's pinMode
//DHT in as O/P.
cfg.direction = BIT(PIN_DHT22);
qm_gpio_set_config(QM_GPIO_0, &cfg);
qm_gpio_set_pin(QM_GPIO_0, PIN_DHT22); /* set HIGH to DHT11 pin */
clk_sys_udelay(250000); /* 250 ms */
//Send DHT start signal
qm_gpio_clear_pin(QM_GPIO_0, PIN_DHT22); /* set DHT11 pin LOW */
clk_sys_udelay(20000); /* 20 ms */
qm_gpio_set_pin(QM_GPIO_0, PIN_DHT22); /* set DHT11 pin HIGH */
clk_sys_udelay(40); /* 40 us */
cfg.direction = 0;
qm_gpio_set_config(QM_GPIO_0, &cfg); //Setting the DHT11 pin as I/P to
//start listening from sensor
qm_gpio_clear_pin(QM_GPIO_0, PIN_DHT22);
clk_sys_udelay(10); //10 us
if(!expectPulse(false))
{
QM_PUTS("Timeout waiting for start signal low pulse.");
//continue;
}
if(!expectPulse(true))
{
QM_PUTS("Timeout waiting for start signal high pulse.");
//continue;
}
for (i=0; i<80; i+=2)
{
cycles[i] = expectPulse(0);
cycles[i+1] = expectPulse(1);
}
// Inspect pulses and determine which ones are 0 (high state cycle count < low
// state cycle count), or 1 (high state cycle count > low state cycle count).
for (i=0; i<40; ++i)
{
uint32_t lowCycles = cycles[2*i];
uint32_t highCycles = cycles[2*i+1];
if ((lowCycles == 0) || (highCycles == 0))
{
QM_PUTS("Timeout waiting for pulse.");
//continue ;
}
data[i/8] <<= 1;
//Now compare the low and high cycle times to see if the bit is a 0 or 1
if (highCycles > lowCycles)
{
// High cycles are greater than 50us low cycle count, must be a 1
data[i/8] |= 1;
}
// Else high cycles are less than (or equal to, a weird case) the 50us low
// cycle count so this must be a zero. Nothing needs to be changed in the
// stored data.
}
QM_PRINTF("Receive %d %d %d %d %d\n",data[0],data[1],data[2],data[3],data[4]);
uint8_t TempF = data[2]*1.8+32;
QM_PRINTF("h : %d, t : %d, f : %d \n", data[0],data[2],TempF);
QM_PRINTF("h: %d , data:%d \n", data[0], data[1]);
//Check we read 40 bits and that the checksum matches
if (data[4] == ((data[0] + data[1] + data[2] + data[3]) & 0xFF))
{
}
else
{
QM_PUTS("Checksum failure!");
}
}
return 0;
}
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