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Improve dallas timing (#3181)

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* Improve dallas timing

* Format
This commit is contained in:
Otto Winter 2022-02-11 09:06:06 +01:00 committed by GitHub
parent 72e716cdf1
commit 3a67884451
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GPG key ID: 4AEE18F83AFDEB23
3 changed files with 149 additions and 96 deletions
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66
esphome/components/dallas/dallas_component.cpp
View file

@ -32,6 +32,11 @@ void DallasComponent::setup() {
ESP_LOGCONFIG(TAG, "Setting up DallasComponent...");
pin_->setup();
// clear bus with 480µs high, otherwise initial reset in search_vec() fails
pin_->pin_mode(gpio::FLAG_INPUT | gpio::FLAG_PULLUP);
delayMicroseconds(480);
one_wire_ = new ESPOneWire(pin_); // NOLINT(cppcoreguidelines-owning-memory)
std::vector<uint64_t> raw_sensors;
@ -99,20 +104,22 @@ void DallasComponent::update() {
this->status_clear_warning();
bool result;
if (!this->one_wire_->reset()) {
result = false;
} else {
result = true;
this->one_wire_->skip();
this->one_wire_->write8(DALLAS_COMMAND_START_CONVERSION);
{
InterruptLock lock;
result = this->one_wire_->reset();
}
if (!result) {
ESP_LOGE(TAG, "Requesting conversion failed");
this->status_set_warning();
return;
}
{
InterruptLock lock;
this->one_wire_->skip();
this->one_wire_->write8(DALLAS_COMMAND_START_CONVERSION);
}
for (auto *sensor : this->sensors_) {
this->set_timeout(sensor->get_address_name(), sensor->millis_to_wait_for_conversion(), [this, sensor] {
bool res = sensor->read_scratch_pad();
@ -152,16 +159,26 @@ const std::string &DallasTemperatureSensor::get_address_name() {
}
bool IRAM_ATTR DallasTemperatureSensor::read_scratch_pad() {
auto *wire = this->parent_->one_wire_;
if (!wire->reset()) {
return false;
{
InterruptLock lock;
if (!wire->reset()) {
return false;
}
}
wire->select(this->address_);
wire->write8(DALLAS_COMMAND_READ_SCRATCH_PAD);
{
InterruptLock lock;
for (unsigned char &i : this->scratch_pad_) {
i = wire->read8();
wire->select(this->address_);
wire->write8(DALLAS_COMMAND_READ_SCRATCH_PAD);
for (unsigned char &i : this->scratch_pad_) {
i = wire->read8();
}
}
return true;
}
bool DallasTemperatureSensor::setup_sensor() {
@ -200,17 +217,20 @@ bool DallasTemperatureSensor::setup_sensor() {
}
auto *wire = this->parent_->one_wire_;
if (wire->reset()) {
wire->select(this->address_);
wire->write8(DALLAS_COMMAND_WRITE_SCRATCH_PAD);
wire->write8(this->scratch_pad_[2]); // high alarm temp
wire->write8(this->scratch_pad_[3]); // low alarm temp
wire->write8(this->scratch_pad_[4]); // resolution
wire->reset();
{
InterruptLock lock;
if (wire->reset()) {
wire->select(this->address_);
wire->write8(DALLAS_COMMAND_WRITE_SCRATCH_PAD);
wire->write8(this->scratch_pad_[2]); // high alarm temp
wire->write8(this->scratch_pad_[3]); // low alarm temp
wire->write8(this->scratch_pad_[4]); // resolution
wire->reset();
// write value to EEPROM
wire->select(this->address_);
wire->write8(0x48);
// write value to EEPROM
wire->select(this->address_);
wire->write8(0x48);
}
}
delay(20); // allow it to finish operation

177
esphome/components/dallas/esp_one_wire.cpp
View file

@ -15,8 +15,6 @@ ESPOneWire::ESPOneWire(InternalGPIOPin *pin) { pin_ = pin->to_isr(); }
bool HOT IRAM_ATTR ESPOneWire::reset() {
// See reset here:
// https://www.maximintegrated.com/en/design/technical-documents/app-notes/1/126.html
InterruptLock lock;
// Wait for communication to clear (delay G)
pin_.pin_mode(gpio::FLAG_INPUT | gpio::FLAG_PULLUP);
uint8_t retries = 125;
@ -43,16 +41,18 @@ bool HOT IRAM_ATTR ESPOneWire::reset() {
}
void HOT IRAM_ATTR ESPOneWire::write_bit(bool bit) {
// See write 1/0 bit here:
// https://www.maximintegrated.com/en/design/technical-documents/app-notes/1/126.html
InterruptLock lock;
// drive bus low
pin_.pin_mode(gpio::FLAG_OUTPUT);
pin_.digital_write(false);
uint32_t delay0 = bit ? 10 : 65;
uint32_t delay1 = bit ? 55 : 5;
// from datasheet:
// write 0 low time: t_low0: min=60µs, max=120µs
// write 1 low time: t_low1: min=1µs, max=15µs
// time slot: t_slot: min=60µs, max=120µs
// recovery time: t_rec: min=1µs
// ds18b20 appears to read the bus after roughly 14µs
uint32_t delay0 = bit ? 6 : 60;
uint32_t delay1 = bit ? 54 : 5;
// delay A/C
delayMicroseconds(delay0);
@ -63,72 +63,100 @@ void HOT IRAM_ATTR ESPOneWire::write_bit(bool bit) {
}
bool HOT IRAM_ATTR ESPOneWire::read_bit() {
// See read bit here:
// https://www.maximintegrated.com/en/design/technical-documents/app-notes/1/126.html
InterruptLock lock;
// drive bus low, delay A
// drive bus low
pin_.pin_mode(gpio::FLAG_OUTPUT);
pin_.digital_write(false);
// note: for reading we'll need very accurate timing, as the
// timing for the digital_read() is tight; according to the datasheet,
// we should read at the end of 16µs starting from the bus low
// typically, the ds18b20 pulls the line high after 11µs for a logical 1
// and 29µs for a logical 0
uint32_t start = micros();
// datasheet says >1µs
delayMicroseconds(3);
// release bus, delay E
pin_.pin_mode(gpio::FLAG_INPUT | gpio::FLAG_PULLUP);
delayMicroseconds(10);
// Unfortunately some frameworks have different characteristics than others
// esp32 arduino appears to pull the bus low only after the digital_write(false),
// whereas on esp-idf it already happens during the pin_mode(OUTPUT)
// manually correct for this with these constants.
#ifdef USE_ESP32_FRAMEWORK_ARDUINO
uint32_t timing_constant = 14;
#elif defined(USE_ESP32_FRAMEWORK_ESP_IDF)
uint32_t timing_constant = 12;
#else
uint32_t timing_constant = 14;
#endif
// measure from start value directly, to get best accurate timing no matter
// how long pin_mode/delayMicroseconds took
while (micros() - start < timing_constant)
;
// sample bus to read bit from peer
bool r = pin_.digital_read();
// delay F
delayMicroseconds(53);
// read slot is at least 60µs; get as close to 60µs to spend less time with interrupts locked
uint32_t now = micros();
if (now - start < 60)
delayMicroseconds(60 - (now - start));
return r;
}
void ESPOneWire::write8(uint8_t val) {
void IRAM_ATTR ESPOneWire::write8(uint8_t val) {
for (uint8_t i = 0; i < 8; i++) {
this->write_bit(bool((1u << i) & val));
}
}
void ESPOneWire::write64(uint64_t val) {
void IRAM_ATTR ESPOneWire::write64(uint64_t val) {
for (uint8_t i = 0; i < 64; i++) {
this->write_bit(bool((1ULL << i) & val));
}
}
uint8_t ESPOneWire::read8() {
uint8_t IRAM_ATTR ESPOneWire::read8() {
uint8_t ret = 0;
for (uint8_t i = 0; i < 8; i++) {
ret |= (uint8_t(this->read_bit()) << i);
}
return ret;
}
uint64_t ESPOneWire::read64() {
uint64_t IRAM_ATTR ESPOneWire::read64() {
uint64_t ret = 0;
for (uint8_t i = 0; i < 8; i++) {
ret |= (uint64_t(this->read_bit()) << i);
}
return ret;
}
void ESPOneWire::select(uint64_t address) {
void IRAM_ATTR ESPOneWire::select(uint64_t address) {
this->write8(ONE_WIRE_ROM_SELECT);
this->write64(address);
}
void ESPOneWire::reset_search() {
void IRAM_ATTR ESPOneWire::reset_search() {
this->last_discrepancy_ = 0;
this->last_device_flag_ = false;
this->last_family_discrepancy_ = 0;
this->rom_number_ = 0;
}
uint64_t ESPOneWire::search() {
uint64_t IRAM_ATTR ESPOneWire::search() {
if (this->last_device_flag_) {
return 0u;
}
if (!this->reset()) {
// Reset failed or no devices present
this->reset_search();
return 0u;
{
InterruptLock lock;
if (!this->reset()) {
// Reset failed or no devices present
this->reset_search();
return 0u;
}
}
uint8_t id_bit_number = 1;
@ -137,58 +165,61 @@ uint64_t ESPOneWire::search() {
bool search_result = false;
uint8_t rom_byte_mask = 1;
// Initiate search
this->write8(ONE_WIRE_ROM_SEARCH);
do {
// read bit
bool id_bit = this->read_bit();
// read its complement
bool cmp_id_bit = this->read_bit();
{
InterruptLock lock;
// Initiate search
this->write8(ONE_WIRE_ROM_SEARCH);
do {
// read bit
bool id_bit = this->read_bit();
// read its complement
bool cmp_id_bit = this->read_bit();
if (id_bit && cmp_id_bit) {
// No devices participating in search
break;
}
bool branch;
if (id_bit != cmp_id_bit) {
// only chose one branch, the other one doesn't have any devices.
branch = id_bit;
} else {
// there are devices with both 0s and 1s at this bit
if (id_bit_number < this->last_discrepancy_) {
branch = (this->rom_number8_()[rom_byte_number] & rom_byte_mask) > 0;
} else {
branch = id_bit_number == this->last_discrepancy_;
if (id_bit && cmp_id_bit) {
// No devices participating in search
break;
}
if (!branch) {
last_zero = id_bit_number;
if (last_zero < 9) {
this->last_discrepancy_ = last_zero;
bool branch;
if (id_bit != cmp_id_bit) {
// only chose one branch, the other one doesn't have any devices.
branch = id_bit;
} else {
// there are devices with both 0s and 1s at this bit
if (id_bit_number < this->last_discrepancy_) {
branch = (this->rom_number8_()[rom_byte_number] & rom_byte_mask) > 0;
} else {
branch = id_bit_number == this->last_discrepancy_;
}
if (!branch) {
last_zero = id_bit_number;
if (last_zero < 9) {
this->last_discrepancy_ = last_zero;
}
}
}
}
if (branch) {
// set bit
this->rom_number8_()[rom_byte_number] |= rom_byte_mask;
} else {
// clear bit
this->rom_number8_()[rom_byte_number] &= ~rom_byte_mask;
}
if (branch) {
// set bit
this->rom_number8_()[rom_byte_number] |= rom_byte_mask;
} else {
// clear bit
this->rom_number8_()[rom_byte_number] &= ~rom_byte_mask;
}
// choose/announce branch
this->write_bit(branch);
id_bit_number++;
rom_byte_mask <<= 1;
if (rom_byte_mask == 0u) {
// go to next byte
rom_byte_number++;
rom_byte_mask = 1;
}
} while (rom_byte_number < 8); // loop through all bytes
// choose/announce branch
this->write_bit(branch);
id_bit_number++;
rom_byte_mask <<= 1;
if (rom_byte_mask == 0u) {
// go to next byte
rom_byte_number++;
rom_byte_mask = 1;
}
} while (rom_byte_number < 8); // loop through all bytes
}
if (id_bit_number >= 65) {
this->last_discrepancy_ = last_zero;
@ -217,7 +248,7 @@ std::vector<uint64_t> ESPOneWire::search_vec() {
return res;
}
void ESPOneWire::skip() {
void IRAM_ATTR ESPOneWire::skip() {
this->write8(0xCC); // skip ROM
}

2
esphome/core/helpers.cpp
View file

@ -328,6 +328,8 @@ void hsv_to_rgb(int hue, float saturation, float value, float &red, float &green
IRAM_ATTR InterruptLock::InterruptLock() { xt_state_ = xt_rsil(15); }
IRAM_ATTR InterruptLock::~InterruptLock() { xt_wsr_ps(xt_state_); }
#elif defined(USE_ESP32)
// only affects the executing core
// so should not be used as a mutex lock, only to get accurate timing
IRAM_ATTR InterruptLock::InterruptLock() { portDISABLE_INTERRUPTS(); }
IRAM_ATTR InterruptLock::~InterruptLock() { portENABLE_INTERRUPTS(); }
#endif