72 lines
2.0 KiB
C++
72 lines
2.0 KiB
C++
#include "ds18b20.h"
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DS18B20::DS18B20(PIO pio, uint8_t gpio) : pio{pio}, gpio{gpio} {
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uint offset = pio_add_program(pio, &ds18b20_program);
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stateMachineIndex = pio_claim_unused_sm(pio, true);
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pio_gpio_init(pio, gpio);
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pio_sm_config c = ds18b20_program_get_default_config(offset);
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sm_config_set_clkdiv_int_frac(&c, 255, 0);
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sm_config_set_set_pins(&c, gpio, 1);
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sm_config_set_out_pins(&c, gpio, 1);
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sm_config_set_in_pins(&c, gpio);
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sm_config_set_in_shift(&c, true, true, 8);
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pio_sm_init(pio0, stateMachineIndex, offset, &c);
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pio_sm_set_enabled(pio0, stateMachineIndex, true);
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}
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void DS18B20::writeBytes(uint8_t bytes[], int len) {
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pio_sm_put_blocking(pio, stateMachineIndex, 250);
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pio_sm_put_blocking(pio, stateMachineIndex, len - 1);
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for (int i = 0; i < len; i++) {
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pio_sm_put_blocking(pio, stateMachineIndex, bytes[i]);
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}
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}
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void DS18B20::readBytes(uint8_t bytes[], int len) {
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pio_sm_put_blocking(pio, stateMachineIndex, 0);
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pio_sm_put_blocking(pio, stateMachineIndex, len - 1);
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for (int i = 0; i < len; i++) {
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bytes[i] = pio_sm_get_blocking(pio, stateMachineIndex) >> 24;
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}
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}
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void DS18B20::convert() {
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uint8_t d[2] = {0xCC, 0x44};
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writeBytes(d, 2);
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}
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uint8_t DS18B20::crc8(uint8_t *data, uint8_t len) {
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uint8_t i;
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uint8_t j;
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uint8_t temp;
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uint8_t databyte;
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uint8_t crc = 0;
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for (i = 0; i < len; i++) {
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databyte = data[i];
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for (j = 0; j < 8; j++) {
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temp = (crc ^ databyte) & 0x01;
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crc >>= 1;
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if (temp)
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crc ^= 0x8C;
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databyte >>= 1;
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}
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}
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return crc;
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}
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float DS18B20::getTemperature() {
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uint8_t d[2] = {0xCC, 0xBE};
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writeBytes(d, 2);
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uint8_t data[9];
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readBytes(data, 9);
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uint8_t crc = crc8(data, 9);
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if (crc != 0)
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return -2000;
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int t1 = data[0];
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int t2 = data[1];
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int16_t temp1 = (t2 << 8 | t1);
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volatile float temp = (float)temp1 / 16;
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return temp;
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} |