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Add a stripped down Add a stripped DHT driver based on ESPEasy (#7717)
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Add a stripped DHT driver based on ESPEasy (#7717)
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@arendst
arendst committed Feb 13, 2020
1 parent a7e9058 commit e9f0c5b
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2 changes: 1 addition & 1 deletion tasmota/xsns_06_dht_v3.ino
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along with this program. If not, see <http://www.gnu.org/licenses/>.
*/

#ifdef USE_DHT
#ifdef USE_DHT_V3
/*********************************************************************************************\
* DHT11, AM2301 (DHT21, DHT22, AM2302, AM2321), SI7021 - Temperature and Humidy
*
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291 changes: 291 additions & 0 deletions tasmota/xsns_06_dht_v4.ino
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/*
xsns_06_dht.ino - DHTxx, AM23xx and SI7021 temperature and humidity sensor support for Tasmota
Copyright (C) 2020 Theo Arends
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/

#ifdef USE_DHT
/*********************************************************************************************\
* DHT11, AM2301 (DHT21, DHT22, AM2302, AM2321), SI7021 - Temperature and Humidy
*
* Reading temperature or humidity takes about 250 milliseconds!
* Sensor readings may also be up to 2 seconds 'old' (its a very slow sensor)
*
* This version is based on ESPEasy _P005_DHT.ino 20191201 and stripped
\*********************************************************************************************/

#define XSNS_06 6

#define DHT_MAX_SENSORS 4
#define DHT_MAX_RETRY 8

uint8_t dht_data[5];
uint8_t dht_sensors = 0;
uint8_t dht_pin_out = 0; // Shelly GPIO00 output only
bool dht_active = true; // DHT configured
bool dht_dual_mode = false; // Single pin mode

struct DHTSTRUCT {
uint8_t pin;
uint8_t type;
char stype[12];
uint32_t lastreadtime;
uint8_t lastresult;
float t = NAN;
float h = NAN;
} Dht[DHT_MAX_SENSORS];

bool DhtExpectPulse(uint32_t sensor, uint32_t level)
{
unsigned long timeout = micros() + 100;
while (digitalRead(Dht[sensor].pin) != level) {
if (micros() > timeout) { return false; }
delayMicroseconds(1);
}
return true;
}

bool DhtRead(uint32_t sensor)
{
dht_data[0] = dht_data[1] = dht_data[2] = dht_data[3] = dht_data[4] = 0;

if (!dht_dual_mode) {
pinMode(Dht[sensor].pin, OUTPUT);
digitalWrite(Dht[sensor].pin, LOW);
} else {
digitalWrite(dht_pin_out, LOW);
}

switch (Dht[sensor].type) {
case GPIO_DHT11: // DHT11
delay(19); // minimum 18ms
break;
case GPIO_DHT22: // DHT21, DHT22, AM2301, AM2302, AM2321
delay(2); // minimum 1ms
break;
case GPIO_SI7021: // iTead SI7021
delayMicroseconds(500);
break;
}

if (!dht_dual_mode) {
pinMode(Dht[sensor].pin, INPUT_PULLUP);
} else {
digitalWrite(dht_pin_out, HIGH);
}

switch (Dht[sensor].type) {
case GPIO_DHT11: // DHT11
case GPIO_DHT22: // DHT21, DHT22, AM2301, AM2302, AM2321
delayMicroseconds(50);
break;
case GPIO_SI7021: // iTead SI7021
delayMicroseconds(20); // See: https://github.com/letscontrolit/ESPEasy/issues/1798
break;
}

uint32_t level = 9;
noInterrupts();
for (uint32_t i = 0; i < 3; i++) {
level = i &1;
if (!DhtExpectPulse(sensor, level)) { break; } // Expect LOW, HIGH, LOW
level = 9;
}
if (9 == level) {
int data = 0;
for (uint32_t i = 0; i < 5; i++) {
data = 0;
for (uint32_t j = 0; j < 8; j++) {
level = 1;
if (!DhtExpectPulse(sensor, level)) { break; } // Expect HIGH

delayMicroseconds(35); // Was 30
if (digitalRead(Dht[sensor].pin)) {
data |= (1 << (7 - j));
}

level = 0;
if (!DhtExpectPulse(sensor, level)) { break; } // Expect LOW
level = 9;
}
if (level < 2) { break; }

dht_data[i] = data;
}
}
interrupts();
if (level < 2) {
AddLog_P2(LOG_LEVEL_DEBUG, PSTR(D_LOG_DHT D_TIMEOUT_WAITING_FOR " %s " D_PULSE), (0 == level) ? D_START_SIGNAL_LOW : D_START_SIGNAL_HIGH);
return false;
}

uint8_t checksum = (dht_data[0] + dht_data[1] + dht_data[2] + dht_data[3]) & 0xFF;
if (dht_data[4] != checksum) {
char hex_char[15];
AddLog_P2(LOG_LEVEL_DEBUG, PSTR(D_LOG_DHT D_CHECKSUM_FAILURE " %s =? %02X"),
ToHex_P(dht_data, 5, hex_char, sizeof(hex_char), ' '), checksum);
return false;
}

return true;
}

void DhtReadTempHum(uint32_t sensor)
{
if ((NAN == Dht[sensor].h) || (Dht[sensor].lastresult > DHT_MAX_RETRY)) { // Reset after 8 misses
Dht[sensor].t = NAN;
Dht[sensor].h = NAN;
}
if (DhtRead(sensor)) {
switch (Dht[sensor].type) {
case GPIO_DHT11:
Dht[sensor].h = dht_data[0];
Dht[sensor].t = dht_data[2] + ((float)dht_data[3] * 0.1f); // Issue #3164
break;
case GPIO_DHT22:
case GPIO_SI7021:
Dht[sensor].h = ((dht_data[0] << 8) | dht_data[1]) * 0.1;
Dht[sensor].t = (((dht_data[2] & 0x7F) << 8 ) | dht_data[3]) * 0.1;
if (dht_data[2] & 0x80) {
Dht[sensor].t *= -1;
}
break;
}
Dht[sensor].t = ConvertTemp(Dht[sensor].t);
Dht[sensor].h = ConvertHumidity(Dht[sensor].h);
Dht[sensor].lastresult = 0;
} else {
Dht[sensor].lastresult++;
}
}

/********************************************************************************************/

bool DhtPinState()
{
if ((XdrvMailbox.index >= GPIO_DHT11) && (XdrvMailbox.index <= GPIO_SI7021)) {
if (dht_sensors < DHT_MAX_SENSORS) {
Dht[dht_sensors].pin = XdrvMailbox.payload;
Dht[dht_sensors].type = XdrvMailbox.index;
dht_sensors++;
XdrvMailbox.index = GPIO_DHT11;
} else {
XdrvMailbox.index = 0;
}
return true;
}
return false;
}

void DhtInit(void)
{
if (dht_sensors) {
if (pin[GPIO_DHT11_OUT] < 99) {
dht_pin_out = pin[GPIO_DHT11_OUT];
dht_dual_mode = true; // Dual pins mode as used by Shelly
dht_sensors = 1; // We only support one sensor in pseudo mode
pinMode(dht_pin_out, OUTPUT);
}

for (uint32_t i = 0; i < dht_sensors; i++) {
pinMode(Dht[i].pin, INPUT_PULLUP);
Dht[i].lastreadtime = 0;
Dht[i].lastresult = 0;
GetTextIndexed(Dht[i].stype, sizeof(Dht[i].stype), Dht[i].type, kSensorNames);
if (dht_sensors > 1) {
snprintf_P(Dht[i].stype, sizeof(Dht[i].stype), PSTR("%s%c%02d"), Dht[i].stype, IndexSeparator(), Dht[i].pin);
}
}
AddLog_P2(LOG_LEVEL_DEBUG, PSTR(D_LOG_DHT "(v4) " D_SENSORS_FOUND " %d"), dht_sensors);
} else {
dht_active = false;
}
}

void DhtEverySecond(void)
{
if (uptime &1) {
} else {
for (uint32_t i = 0; i < dht_sensors; i++) {
// DHT11 and AM2301 25mS per sensor, SI7021 5mS per sensor
DhtReadTempHum(i);
}
}
}

void DhtShow(bool json)
{
for (uint32_t i = 0; i < dht_sensors; i++) {
char temperature[33];
dtostrfd(Dht[i].t, Settings.flag2.temperature_resolution, temperature);
char humidity[33];
dtostrfd(Dht[i].h, Settings.flag2.humidity_resolution, humidity);

if (json) {
ResponseAppend_P(JSON_SNS_TEMPHUM, Dht[i].stype, temperature, humidity);
#ifdef USE_DOMOTICZ
if ((0 == tele_period) && (0 == i)) {
DomoticzTempHumSensor(temperature, humidity);
}
#endif // USE_DOMOTICZ
#ifdef USE_KNX
if ((0 == tele_period) && (0 == i)) {
KnxSensor(KNX_TEMPERATURE, Dht[i].t);
KnxSensor(KNX_HUMIDITY, Dht[i].h);
}
#endif // USE_KNX
#ifdef USE_WEBSERVER
} else {
WSContentSend_PD(HTTP_SNS_TEMP, Dht[i].stype, temperature, TempUnit());
WSContentSend_PD(HTTP_SNS_HUM, Dht[i].stype, humidity);
#endif // USE_WEBSERVER
}
}
}

/*********************************************************************************************\
* Interface
\*********************************************************************************************/

bool Xsns06(uint8_t function)
{
bool result = false;

if (dht_active) {
switch (function) {
case FUNC_EVERY_SECOND:
DhtEverySecond();
break;
case FUNC_JSON_APPEND:
DhtShow(1);
break;
#ifdef USE_WEBSERVER
case FUNC_WEB_SENSOR:
DhtShow(0);
break;
#endif // USE_WEBSERVER
case FUNC_INIT:
DhtInit();
break;
case FUNC_PIN_STATE:
result = DhtPinState();
break;
}
}
return result;
}

#endif // USE_DHT

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