Paul Staron
Fork of Erik's DS1820 library working on OS6
Dependents: DS1820-example DS1820mitWebserver DS1820ohneWebserver
Diff: DS1820.cpp
- Revision:
- 0:a43dcf6ca539
diff -r 000000000000 -r a43dcf6ca539 DS1820.cpp
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/DS1820.cpp Tue Dec 29 13:08:05 2020 +0000
@@ -0,0 +1,426 @@
+#include "DS1820.h"
+
+#ifdef TARGET_STM
+//STM targets use opendrain mode since their switching between input and output is slow
+ #define ONEWIRE_INPUT(pin) pin->write(1)
+ #define ONEWIRE_OUTPUT(pin)
+ #define ONEWIRE_INIT(pin) pin->output(); pin->mode(OpenDrain)
+#else
+ #define ONEWIRE_INPUT(pin) pin->input()
+ #define ONEWIRE_OUTPUT(pin) pin->output()
+ #define ONEWIRE_INIT(pin)
+#endif
+
+#ifdef TARGET_NORDIC
+//NORDIC targets (NRF) use software delays since their ticker uses a 32kHz clock
+ static uint32_t loops_per_us = 0;
+
+ #define INIT_DELAY init_soft_delay()
+ #define ONEWIRE_DELAY_US(value) for(int cnt = 0; cnt < (value * loops_per_us) >> 5; cnt++) {__NOP(); __NOP(); __NOP();}
+
+void init_soft_delay( void ) {
+ if (loops_per_us == 0) {
+ loops_per_us = 1;
+ Timer timey;
+ timey.start();
+ ONEWIRE_DELAY_US(320000);
+ timey.stop();
+ loops_per_us = (320000 + timey.read_us() / 2) / timey.read_us();
+ }
+}
+#else
+ #define INIT_DELAY
+ #define ONEWIRE_DELAY_US(value) wait_us(value)
+#endif
+
+LinkedList2<node> DS1820::probes;
+
+
+DS1820::DS1820 (PinName data_pin, PinName power_pin, bool power_polarity) : _datapin(data_pin), _parasitepin(power_pin) {
+ int byte_counter;
+ _power_polarity = power_polarity;
+
+ _power_mosfet = power_pin != NC;
+
+ for(byte_counter=0;byte_counter<9;byte_counter++)
+ RAM[byte_counter] = 0x00;
+
+ ONEWIRE_INIT((&_datapin));
+ INIT_DELAY;
+
+ if (!unassignedProbe(&_datapin, _ROM))
+ error("No unassigned DS1820 found!\n");
+ else {
+ _datapin.input();
+ probes.append(this);
+ _parasite_power = !read_power_supply();
+ }
+}
+
+DS1820::~DS1820 (void) {
+ node *tmp;
+ for(int i=1; i<=probes.length(); i++)
+ {
+ tmp = probes.pop(i);
+ if (tmp->data == this)
+ probes.remove(i);
+ }
+}
+
+bool DS1820::onewire_reset(DigitalInOut *pin) {
+// This will return false if no devices are present on the data bus
+ bool presence=false;
+ ONEWIRE_OUTPUT(pin);
+ pin->write(0); // bring low for 500 us
+ ONEWIRE_DELAY_US(500);
+ ONEWIRE_INPUT(pin); // let the data line float high
+ ONEWIRE_DELAY_US(90); // wait 90us
+ if (pin->read()==0) // see if any devices are pulling the data line low
+ presence=true;
+ ONEWIRE_DELAY_US(410);
+ return presence;
+}
+
+void DS1820::onewire_bit_out (DigitalInOut *pin, bool bit_data) {
+ ONEWIRE_OUTPUT(pin);
+ pin->write(0);
+ ONEWIRE_DELAY_US(3); // DXP modified from 5
+ if (bit_data) {
+ pin->write(1); // bring data line high
+ ONEWIRE_DELAY_US(55);
+ } else {
+ ONEWIRE_DELAY_US(55); // keep data line low
+ pin->write(1);
+ ONEWIRE_DELAY_US(10); // DXP added to allow bus to float high before next bit_out
+ }
+}
+
+void DS1820::onewire_byte_out(char data) { // output data character (least sig bit first).
+ int n;
+ for (n=0; n<8; n++) {
+ onewire_bit_out(&this->_datapin, data & 0x01);
+ data = data >> 1; // now the next bit is in the least sig bit position.
+ }
+}
+
+bool DS1820::onewire_bit_in(DigitalInOut *pin) {
+ bool answer;
+ ONEWIRE_OUTPUT(pin);
+ pin->write(0);
+ ONEWIRE_DELAY_US(3); // DXP modofied from 5
+ ONEWIRE_INPUT(pin);
+ ONEWIRE_DELAY_US(6); // DXP modified from 5
+ answer = pin->read();
+ ONEWIRE_DELAY_US(45); // DXP modified from 50
+ return answer;
+}
+
+char DS1820::onewire_byte_in() { // read byte, least sig byte first
+ char answer = 0x00;
+ int i;
+ for (i=0; i<8; i++) {
+ answer = answer >> 1; // shift over to make room for the next bit
+ if (onewire_bit_in(&this->_datapin))
+ answer = answer | 0x80; // if the data port is high, make this bit a 1
+ }
+ return answer;
+}
+
+bool DS1820::unassignedProbe(PinName pin) {
+ DigitalInOut _pin(pin);
+ ONEWIRE_INIT((&_pin));
+ INIT_DELAY;
+ char ROM_address[8];
+ return search_ROM_routine(&_pin, 0xF0, ROM_address);
+}
+
+bool DS1820::unassignedProbe(DigitalInOut *pin, char *ROM_address) {
+ return search_ROM_routine(pin, 0xF0, ROM_address);
+}
+
+bool DS1820::search_ROM_routine(DigitalInOut *pin, char command, char *ROM_address) {
+ bool DS1820_done_flag = false;
+ int DS1820_last_descrepancy = 0;
+ char DS1820_search_ROM[8] = {0, 0, 0, 0, 0, 0, 0, 0};
+
+ int descrepancy_marker, ROM_bit_index;
+ bool return_value, Bit_A, Bit_B;
+ char byte_counter, bit_mask;
+
+ return_value=false;
+ while (!DS1820_done_flag) {
+ if (!onewire_reset(pin)) {
+ return false;
+ } else {
+ ROM_bit_index=1;
+ descrepancy_marker=0;
+ char command_shift = command;
+ for (int n=0; n<8; n++) { // Search ROM command or Search Alarm command
+ onewire_bit_out(pin, command_shift & 0x01);
+ command_shift = command_shift >> 1; // now the next bit is in the least sig bit position.
+ }
+ byte_counter = 0;
+ bit_mask = 0x01;
+ while (ROM_bit_index<=64) {
+ Bit_A = onewire_bit_in(pin);
+ Bit_B = onewire_bit_in(pin);
+ if (Bit_A & Bit_B) {
+ descrepancy_marker = 0; // data read error, this should never happen
+ ROM_bit_index = 0xFF;
+ } else {
+ if (Bit_A | Bit_B) {
+ // Set ROM bit to Bit_A
+ if (Bit_A) {
+ DS1820_search_ROM[byte_counter] = DS1820_search_ROM[byte_counter] | bit_mask; // Set ROM bit to one
+ } else {
+ DS1820_search_ROM[byte_counter] = DS1820_search_ROM[byte_counter] & ~bit_mask; // Set ROM bit to zero
+ }
+ } else {
+ // both bits A and B are low, so there are two or more devices present
+ if ( ROM_bit_index == DS1820_last_descrepancy ) {
+ DS1820_search_ROM[byte_counter] = DS1820_search_ROM[byte_counter] | bit_mask; // Set ROM bit to one
+ } else {
+ if ( ROM_bit_index > DS1820_last_descrepancy ) {
+ DS1820_search_ROM[byte_counter] = DS1820_search_ROM[byte_counter] & ~bit_mask; // Set ROM bit to zero
+ descrepancy_marker = ROM_bit_index;
+ } else {
+ if (( DS1820_search_ROM[byte_counter] & bit_mask) == 0x00 )
+ descrepancy_marker = ROM_bit_index;
+ }
+ }
+ }
+ onewire_bit_out (pin, DS1820_search_ROM[byte_counter] & bit_mask);
+ ROM_bit_index++;
+ if (bit_mask & 0x80) {
+ byte_counter++;
+ bit_mask = 0x01;
+ } else {
+ bit_mask = bit_mask << 1;
+ }
+ }
+ }
+ DS1820_last_descrepancy = descrepancy_marker;
+ if (ROM_bit_index != 0xFF) {
+ int i = 1;
+ node *list_container;
+ while(1) {
+ list_container = probes.pop(i);
+ if (list_container == NULL) { //End of list, or empty list
+ if (ROM_checksum_error(DS1820_search_ROM)) { // Check the CRC
+ return false;
+ }
+ for(byte_counter=0;byte_counter<8;byte_counter++)
+ ROM_address[byte_counter] = DS1820_search_ROM[byte_counter];
+ return true;
+ } else { //Otherwise, check if ROM is already known
+ bool equal = true;
+ DS1820 *pointer = (DS1820*) list_container->data;
+ char *ROM_compare = pointer->_ROM;
+
+ for(byte_counter=0;byte_counter<8;byte_counter++) {
+ if ( ROM_compare[byte_counter] != DS1820_search_ROM[byte_counter])
+ equal = false;
+ }
+ if (equal)
+ break;
+ else
+ i++;
+ }
+ }
+ }
+ }
+ if (DS1820_last_descrepancy == 0)
+ DS1820_done_flag = true;
+ }
+ return return_value;
+}
+
+void DS1820::match_ROM() {
+// Used to select a specific device
+ int i;
+ onewire_reset(&this->_datapin);
+ onewire_byte_out( 0x55); //Match ROM command
+ for (i=0;i<8;i++) {
+ onewire_byte_out(_ROM[i]);
+ }
+}
+
+void DS1820::skip_ROM() {
+ onewire_reset(&this->_datapin);
+ onewire_byte_out(0xCC); // Skip ROM command
+}
+
+bool DS1820::ROM_checksum_error(char *_ROM_address) {
+ char _CRC=0x00;
+ int i;
+ for(i=0;i<7;i++) // Only going to shift the lower 7 bytes
+ _CRC = CRC_byte(_CRC, _ROM_address[i]);
+ // After 7 bytes CRC should equal the 8th byte (ROM CRC)
+ return (_CRC!=_ROM_address[7]); // will return true if there is a CRC checksum mis-match
+}
+
+bool DS1820::RAM_checksum_error() {
+ char _CRC=0x00;
+ int i;
+ for(i=0;i<8;i++) // Only going to shift the lower 8 bytes
+ _CRC = CRC_byte(_CRC, RAM[i]);
+ // After 8 bytes CRC should equal the 9th byte (RAM CRC)
+ return (_CRC!=RAM[8]); // will return true if there is a CRC checksum mis-match
+}
+
+char DS1820::CRC_byte (char _CRC, char byte ) {
+ int j;
+ for(j=0;j<8;j++) {
+ if ((byte & 0x01 ) ^ (_CRC & 0x01)) {
+ // DATA ^ LSB CRC = 1
+ _CRC = _CRC>>1;
+ // Set the MSB to 1
+ _CRC = _CRC | 0x80;
+ // Check bit 3
+ if (_CRC & 0x04) {
+ _CRC = _CRC & 0xFB; // Bit 3 is set, so clear it
+ } else {
+ _CRC = _CRC | 0x04; // Bit 3 is clear, so set it
+ }
+ // Check bit 4
+ if (_CRC & 0x08) {
+ _CRC = _CRC & 0xF7; // Bit 4 is set, so clear it
+ } else {
+ _CRC = _CRC | 0x08; // Bit 4 is clear, so set it
+ }
+ } else {
+ // DATA ^ LSB CRC = 0
+ _CRC = _CRC>>1;
+ // clear MSB
+ _CRC = _CRC & 0x7F;
+ // No need to check bits, with DATA ^ LSB CRC = 0, they will remain unchanged
+ }
+ byte = byte>>1;
+ }
+return _CRC;
+}
+
+int DS1820::convertTemperature(bool wait, devices device) {
+ // Convert temperature into scratchpad RAM for all devices at once
+ int delay_time = 750000; // Default delay time
+ char resolution;
+ if (device==all_devices)
+ skip_ROM(); // Skip ROM command, will convert for ALL devices
+ else {
+ match_ROM();
+ if ((FAMILY_CODE == FAMILY_CODE_DS18B20 ) || (FAMILY_CODE == FAMILY_CODE_DS1822 )) {
+ resolution = RAM[4] & 0x60;
+ if (resolution == 0x00) // 9 bits
+ delay_time = 94000;
+ if (resolution == 0x20) // 10 bits
+ delay_time = 188000;
+ if (resolution == 0x40) // 11 bits. Note 12bits uses the 750ms default
+ delay_time = 375000;
+ }
+ }
+
+ onewire_byte_out( 0x44); // perform temperature conversion
+ if (_parasite_power) {
+ if (_power_mosfet) {
+ _parasitepin = _power_polarity; // Parasite power strong pullup
+ wait_us(delay_time);
+ _parasitepin = !_power_polarity;
+ delay_time = 0;
+ } else {
+ _datapin.output();
+ _datapin.write(1);
+ wait_us(delay_time);
+ _datapin.input();
+ }
+ } else {
+ if (wait) {
+ wait_us(delay_time);
+ delay_time = 0;
+ }
+ }
+ return delay_time;
+}
+
+void DS1820::read_RAM() {
+ // This will copy the DS1820's 9 bytes of RAM data
+ // into the objects RAM array. Functions that use
+ // RAM values will automaticly call this procedure.
+ int i;
+ match_ROM(); // Select this device
+ onewire_byte_out( 0xBE); //Read Scratchpad command
+ for(i=0;i<9;i++) {
+ RAM[i] = onewire_byte_in();
+ }
+// if (!RAM_checksum_error())
+// crcerr = 1;
+}
+
+bool DS1820::setResolution(unsigned int resolution) {
+ bool answer = false;
+ resolution = resolution - 9;
+ if (resolution < 4) {
+ resolution = resolution<<5; // align the bits
+ RAM[4] = (RAM[4] & 0x60) | resolution; // mask out old data, insert new
+ write_scratchpad ((RAM[2]<<8) + RAM[3]);
+ write_scratchpad (DS1820::this_device); // Need to test if this is required
+ answer = true;
+ }
+ return answer;
+}
+
+void DS1820::write_scratchpad(int data) {
+ RAM[3] = data;
+ RAM[2] = data>>8;
+ match_ROM();
+ onewire_byte_out(0x4E); // Copy scratchpad into DS1820 ram memory
+ onewire_byte_out(RAM[2]); // T(H)
+ onewire_byte_out(RAM[3]); // T(L)
+ if ((FAMILY_CODE == FAMILY_CODE_DS18B20 ) || (FAMILY_CODE == FAMILY_CODE_DS1822 )) {
+ onewire_byte_out(RAM[4]); // Configuration register
+ }
+}
+
+float DS1820::temperature(char scale) {
+// The data specs state that count_per_degree should be 0x10 (16), I found my devices
+// to have a count_per_degree of 0x4B (75). With the standard resolution of 1/2 deg C
+// this allowed an expanded resolution of 1/150th of a deg C. I wouldn't rely on this
+// being super acurate, but it does allow for a smooth display in the 1/10ths of a
+// deg C or F scales.
+ float answer, remaining_count, count_per_degree;
+ int reading;
+ read_RAM();
+ if (RAM_checksum_error())
+ // Indicate we got a CRC error
+ answer = invalid_conversion;
+ else {
+ reading = (RAM[1] << 8) + RAM[0];
+ if (reading & 0x8000) { // negative degrees C
+ reading = 0-((reading ^ 0xffff) + 1); // 2's comp then convert to signed int
+ }
+ answer = reading +0.0; // convert to floating point
+ if ((FAMILY_CODE == FAMILY_CODE_DS18B20 ) || (FAMILY_CODE == FAMILY_CODE_DS1822 )) {
+ answer = answer / 16.0f;
+ }
+ else {
+ remaining_count = RAM[6];
+ count_per_degree = RAM[7];
+ answer = floor(answer/2.0f) - 0.25f + (count_per_degree - remaining_count) / count_per_degree;
+ }
+ if (scale=='F' or scale=='f')
+ // Convert to deg F
+ answer = answer * 9.0f / 5.0f + 32.0f;
+ }
+ return answer;
+}
+
+bool DS1820::read_power_supply(devices device) {
+// This will return true if the device (or all devices) are Vcc powered
+// This will return false if the device (or ANY device) is parasite powered
+ if (device==all_devices)
+ skip_ROM(); // Skip ROM command, will poll for any device using parasite power
+ else
+ match_ROM();
+ onewire_byte_out(0xB4); // Read power supply command
+ return onewire_bit_in(&this->_datapin);
+}
+