Implement new ds18b20 APIs

extras/ds18b20/ds18b20.c

@@ -1,7 +1,7 @@
 #include "FreeRTOS.h"
 #include "task.h"
+#include "math.h"
 
-#include "onewire/onewire.h"
 #include "ds18b20.h"
 
 #define DS18B20_WRITE_SCRATCHPAD 0x4E
@@ -16,6 +16,8 @@
 #define DS18B20_ALARMSEARCH      0xEC
 #define DS18B20_CONVERT_T        0x44
 
+#define os_sleep_ms(x) vTaskDelay(((x) + portTICK_RATE_MS - 1) / portTICK_RATE_MS)
+
 uint8_t ds18b20_read_all(uint8_t pin, ds_sensor_t *result) {
     onewire_addr_t addr;
     onewire_search_t search;
@@ -108,3 +110,114 @@ float ds18b20_read_single(uint8_t pin) {
     return temperature;
     //printf("Got a DS18B20 Reading: %d.%02d\n", (int)temperature, (int)(temperature - (int)temperature) * 100);
 }
+
+bool ds18b20_measure(int pin, ds18b20_addr_t addr, bool wait) {
+    if (!onewire_reset(pin)) {
+        return false;
+    }
+    if (addr == DS18B20_ANY) {
+        onewire_skip_rom(pin);
+    } else {
+        onewire_select(pin, addr);
+    }
+    taskENTER_CRITICAL();
+    onewire_write(pin, DS18B20_CONVERT_T);
+    // For parasitic devices, power must be applied within 10us after issuing
+    // the convert command.
+    onewire_power(pin);
+    taskEXIT_CRITICAL();
+
+    if (wait) {
+        os_sleep_ms(750);
+        onewire_depower(pin);
+    }
+
+    return true;
+}
+
+bool ds18b20_read_scratchpad(int pin, ds18b20_addr_t addr, uint8_t *buffer) {
+    uint8_t crc;
+    uint8_t expected_crc;
+
+    if (!onewire_reset(pin)) {
+        return false;
+    }
+    if (addr == DS18B20_ANY) {
+        onewire_skip_rom(pin);
+    } else {
+        onewire_select(pin, addr);
+    }
+    onewire_write(pin, DS18B20_READ_SCRATCHPAD);
+    
+    for (int i = 0; i < 8; i++) {
+        buffer[i] = onewire_read(pin);
+    }
+    crc = onewire_read(pin);
+
+    expected_crc = onewire_crc8(buffer, 8);
+    if (crc != expected_crc) {
+        printf("CRC check failed reading scratchpad: %02x %02x %02x %02x %02x %02x %02x %02x : %02x (expected %02x)\n", buffer[0], buffer[1], buffer[2], buffer[3], buffer[4], buffer[5], buffer[6], buffer[7], crc, expected_crc);
+        return false;
+    }
+
+    return true;
+}
+
+float ds18b20_read_temperature(int pin, ds18b20_addr_t addr) {
+    uint8_t scratchpad[8];
+    int temp;
+
+    if (!ds18b20_read_scratchpad(pin, addr, scratchpad)) {
+        return NAN;
+    }
+
+    temp = scratchpad[1] << 8 | scratchpad[0];
+    
+    return ((float)temp * 625.0)/10000;
+}
+
+float ds18b20_measure_and_read(int pin, ds18b20_addr_t addr) {
+    if (!ds18b20_measure(pin, addr, true)) {
+        return NAN;
+    }
+    return ds18b20_read_temperature(pin, addr);
+}
+
+bool ds18b20_measure_and_read_multi(int pin, ds18b20_addr_t *addr_list, int addr_count, float *result_list) {
+    if (!ds18b20_measure(pin, DS18B20_ANY, true)) {
+        for (int i=0; i < addr_count; i++) {
+            result_list[i] = NAN;
+        }
+        return false;
+    }
+    return ds18b20_read_temp_multi(pin, addr_list, addr_count, result_list);
+}
+
+int ds18b20_scan_devices(int pin, ds18b20_addr_t *addr_list, int addr_count) {
+    onewire_search_t search;
+    onewire_addr_t addr;
+    int found = 0;
+
+    onewire_search_start(&search);
+    while ((addr = onewire_search_next(&search, pin)) != ONEWIRE_NONE) {
+        if (found < addr_count) {
+            addr_list[found] = addr;
+        }
+        found++;
+    }
+    return found;
+}
+
+bool ds18b20_read_temp_multi(int pin, ds18b20_addr_t *addr_list, int addr_count, float *result_list) {
+    bool result = true;
+
+    for (int i = 0; i < addr_count; i++) {
+        result_list[i] = ds18b20_read_temperature(pin, addr_list[i]);
+        if (isnan(result_list[i])) {
+            result = false;
+        }
+    }
+    return result;
+}
+
+