void ICACHE_FLASH_ATTR dht22_init(){
DHT_DBG("dht22_init");
//nothing to do actually
}
void ICACHE_FLASH_ATTR dht22_init() {
DHT_DBG("dht22_init");
os_timer_disarm(&dht_timer);
os_timer_setfn(&dht_timer, (os_timer_func_t *)dht22_timer_cb, NULL);
os_timer_arm(&dht_timer, 5000, 1);
//Start os task
system_os_task(dht22_task, 1 ,taskQueue, 2);
system_os_post(1, SIG_DHT, NULL );
}
static void ICACHE_FLASH_ATTR dht22_task(os_event_t *e) {
DHT_DBG("dht22_task");
if(e->sig != SIG_DHT)
return;
//put dht pin on output mode with pullup
platform_gpio_mode(DHT_PIN,PLATFORM_GPIO_OUTPUT,PLATFORM_GPIO_PULLUP);
uint64_t data;
os_memset(&data,0,sizeof(uint64_t));
//init sequence
platform_gpio_write(DHT_PIN,1);
delay_ms(5);
platform_gpio_write(DHT_PIN,0);
delay_ms(1);
platform_gpio_write(DHT_PIN,1);
//enable input reading
platform_gpio_mode(DHT_PIN,PLATFORM_GPIO_INPUT,PLATFORM_GPIO_PULLUP);
//find ACK start
//wait pin to drop
int timeout = 100;
while(platform_gpio_read(DHT_PIN) == 1 && timeout > 0)
{
os_delay_us(5);
timeout-=5;
}
if(timeout==0) {
DHT_DBG("\tACK start timeout");
return;
}
//find ACK end
//wait pin to rise
timeout = 100;
while(platform_gpio_read(DHT_PIN) == 0 && timeout > 0)
{
os_delay_us(10);
timeout-=10;
}
if(timeout==0) {
DHT_DBG("\tACK end timeout");
return;
}
//continue to read data
while(1) {
//wait pin to go low, signaling next bit
timeout = 200;
while(platform_gpio_read(DHT_PIN) == 1 && timeout > 0)
{
os_delay_us(5);
timeout-=5;
}
if(timeout==0) {
//NODE_DBG("\tdata signal timeout");
break;
}
//wait start of bit
timeout = 200;
while(platform_gpio_read(DHT_PIN) == 0 && timeout > 0)
{
os_delay_us(5);
timeout-=5;
}
if(timeout==0) {
//NODE_DBG("\tdata bit start timeout");
break;
}
//mearure pulse lenght
timeout = 200;
while(platform_gpio_read(DHT_PIN) == 1 && timeout > 0)
{
os_delay_us(5);
timeout-=5;
}
if(timeout==0) {
//NODE_DBG("\tdata bit read timeout");
break;
}
int pulseWidth = 200 - timeout;
//shift data
data <<= 1;
if(pulseWidth > 40)
{
//bit is 1
data |=1;
}
else {
//bit is 0
//nothing to do
}
}
//do the math
float temp_p, hum_p;
uint8_t data_part[5];
data_part[4] = ((uint8_t*)&data)[0];
data_part[3] = ((uint8_t*)&data)[1];
data_part[2] = ((uint8_t*)&data)[2];
data_part[1] = ((uint8_t*)&data)[3];
data_part[0] = ((uint8_t*)&data)[4];
int checksum = (data_part[0] + data_part[1] + data_part[2] + data_part[3]) & 0xFF;
if (data_part[4] == checksum) {
// yay! checksum is valid
hum_p = data_part[0] * 256 + data_part[1];
hum_p /= 10;
temp_p = (data_part[2] & 0x7F)* 256 + data_part[3];
temp_p /= 10.0;
if (data_part[2] & 0x80)
temp_p *= -1;
read.temp = temp_p;
read.hum = hum_p;
}
}
int ICACHE_FLASH_ATTR dht22_read(dht_data *read){
DHT_DBG("dht22_read");
//put dht pin on output mode with pullup
platform_gpio_mode(DHT_PIN,PLATFORM_GPIO_OUTPUT,PLATFORM_GPIO_PULLUP);
uint64_t data;
os_memset(&data,0,sizeof(uint64_t));
//init sequence
platform_gpio_write(DHT_PIN,1);
delay_ms(5);
platform_gpio_write(DHT_PIN,0);
delay_ms(1);
platform_gpio_write(DHT_PIN,1);
//enable input reading
platform_gpio_mode(DHT_PIN,PLATFORM_GPIO_INPUT,PLATFORM_GPIO_PULLUP);
//find ACK start
//wait pin to drop
int timeout = 100;
while(platform_gpio_read(DHT_PIN) == 1 && timeout > 0)
{
os_delay_us(5);
timeout-=5;
}
if(timeout==0){
DHT_DBG("\tACK start timeout");
return 0;
}
//find ACK end
//wait pin to rise
timeout = 100;
while(platform_gpio_read(DHT_PIN) == 0 && timeout > 0)
{
os_delay_us(10);
timeout-=10;
}
if(timeout==0){
DHT_DBG("\tACK end timeout");
return 0;
}
//continue to read data
while(1){
//wait pin to go low, signaling next bit
timeout = 200;
while(platform_gpio_read(DHT_PIN) == 1 && timeout > 0)
{
os_delay_us(5);
timeout-=5;
}
if(timeout==0){
//NODE_DBG("\tdata signal timeout");
break;
}
//wait start of bit
timeout = 200;
while(platform_gpio_read(DHT_PIN) == 0 && timeout > 0)
{
os_delay_us(5);
timeout-=5;
}
if(timeout==0){
//NODE_DBG("\tdata bit start timeout");
break;
}
//mearure pulse lenght
timeout = 200;
while(platform_gpio_read(DHT_PIN) == 1 && timeout > 0)
{
os_delay_us(5);
timeout-=5;
}
if(timeout==0){
//NODE_DBG("\tdata bit read timeout");
break;
}
int pulseWidth = 200 - timeout;
//shift data
data <<= 1;
if(pulseWidth > 40)
{
//bit is 1
data |=1;
}
else{
//bit is 0
//nothing to do
}
}
//do the math
float temp_p, hum_p;
uint8_t data_part[5];
data_part[4] = ((uint8_t*)&data)[0];
data_part[3] = ((uint8_t*)&data)[1];
data_part[2] = ((uint8_t*)&data)[2];
data_part[1] = ((uint8_t*)&data)[3];
data_part[0] = ((uint8_t*)&data)[4];
int checksum = (data_part[0] + data_part[1] + data_part[2] + data_part[3]) & 0xFF;
if (data_part[4] == checksum) {
// yay! checksum is valid
hum_p = data_part[0] * 256 + data_part[1];
hum_p /= 10;
temp_p = (data_part[2] & 0x7F)* 256 + data_part[3];
temp_p /= 10.0;
if (data_part[2] & 0x80)
temp_p *= -1;
read->temp = temp_p;
read->hum = hum_p;
#ifdef DHT_DEBUG_ON
char * buff = (char *)os_zalloc(64);
c_sprintf(buff,"%f",read->temp);
DHT_DBG("dht22_init temp : %s C",buff);
os_memset(buff,0,64);
c_sprintf(buff,"%f",read->hum);
DHT_DBG("dht22_init humidity : %s %%",buff);
os_free(buff);
#endif
}
return 1;
}
