209 lines
6.2 KiB
C
209 lines
6.2 KiB
C
#include "mcp3550.h"
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#include "mcp23018.h"
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#include "driver/gpio.h"
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#include <esp_timer.h>
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#define TAG_MICS "MICS_ADC"
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#define MCP3550_SPS 3.75f
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#define MCP3550_CONVERSION_MS ((int)(1000.0f / MCP3550_SPS)) // ~267ms
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#define MCP3550_TIMEOUT_MS 400
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#define ADC_COUNT 4
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const uint8_t adc_cs_pins[ADC_COUNT] = {
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MCP_CS_ADC_NH3, MCP_CS_ADC_CO, MCP_CS_ADC_NO2, MCP_CS_ADC_UVC
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};
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spi_device_handle_t mcp3550_handle;
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void mcp3550_spi_init()
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{
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// spi_device_interface_config_t devcfg = {
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// .clock_speed_hz = 100000,
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// .mode = 0,
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// .spics_io_num = -1, // We handle CS manually
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// .queue_size = 1,
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// };
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// ESP_ERROR_CHECK(spi_bus_add_device(SPI2_HOST, &devcfg, &mcp3550_handle));
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// Set MISO pin for input (needed for polling)
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gpio_set_direction(MCP3550_MISO_GPIO, GPIO_MODE_INPUT);
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}
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// int32_t mcp3550_read(uint8_t cs_pin)
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// {
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// uint8_t rx_buf[4] = {0}; // 25 bits fits in 4 bytes
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// int64_t start = esp_timer_get_time(); // in microseconds
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// while (true) {
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// mcp23018_set_pin(MCP23018_DEV_HANDLE, cs_pin, 0); // CS LOW
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// vTaskDelay(pdMS_TO_TICKS(30)); // Wait before retrying
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// mcp23018_set_pin(MCP23018_DEV_HANDLE, cs_pin, 1); // CS HIGH
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// vTaskDelay(pdMS_TO_TICKS(200)); // Wait before retrying
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// mcp23018_set_pin(MCP23018_DEV_HANDLE, cs_pin, 0); // CS LOW
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// esp_rom_delay_us(1000); // Wait before retrying
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// spi_transaction_t trans = {
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// .length = 25,
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// .rx_buffer = rx_buf,
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// };
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// esp_err_t err = spi_device_transmit(mcp3550_handle, &trans);
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// mcp23018_set_pin(MCP23018_DEV_HANDLE, cs_pin, 1); // CS HIGH
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// if (err != ESP_OK) {
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// ESP_LOGE(TAG_MICS, "SPI transmit failed on CS pin %u", cs_pin);
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// return INT32_MIN;
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// }
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// bool dr = (rx_buf[0] & 0x80) != 0;
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// if (!dr) break;
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// if ((esp_timer_get_time() - start) > (MCP3550_TIMEOUT_MS * 1000)) {
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// ESP_LOGW(TAG_MICS, "Timeout waiting for DR=0 on CS pin %u", cs_pin);
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// return INT32_MIN;
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// }
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// vTaskDelay(pdMS_TO_TICKS(10)); // Wait before retrying
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// }
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// // Combine 22-bit result (drop DR + status bits)
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// uint32_t raw = ((rx_buf[0] & 0x3F) << 16) | (rx_buf[1] << 8) | rx_buf[2];
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// // Sign-extend 22-bit value
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// int32_t value = raw;
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// if (value & (1 << 21)) value |= 0xFFC00000;
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// return value;
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// }
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// int32_t mcp3550_read(uint8_t cs_pin)
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// {
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// uint8_t rx_buf[4] = {0};
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// uint32_t timeout_us = MCP3550_TIMEOUT_MS * 1000;
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// int64_t start = esp_timer_get_time();
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// // Start conversion
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// mcp23018_set_pin(MCP23018_DEV_HANDLE, cs_pin, 0); // CS LOW
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// // Wait until MISO/SDO goes LOW = DR ready
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// while (gpio_get_level(MCP3550_MISO_GPIO)) {
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// if ((esp_timer_get_time() - start) > timeout_us) {
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// ESP_LOGW(TAG_MICS, "Timeout waiting for MISO=0 on CS %u", cs_pin);
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// mcp23018_set_pin(MCP23018_DEV_HANDLE, cs_pin, 1); // CS HIGH
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// return INT32_MIN;
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// }
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// esp_rom_delay_us(10); // micro delay
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// }
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// // Data is ready, do full SPI read
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// spi_transaction_t trans = {
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// .length = 25, // 25 bits
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// .rx_buffer = rx_buf,
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// };
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// esp_err_t err = spi_device_transmit(mcp3550_handle, &trans);
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// mcp23018_set_pin(MCP23018_DEV_HANDLE, cs_pin, 1); // CS HIGH to start next conversion
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// if (err != ESP_OK) {
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// ESP_LOGE(TAG_MICS, "SPI transmit failed");
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// return INT32_MIN;
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// }
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// // Extract 22-bit result
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// uint32_t raw = ((rx_buf[0] & 0x3F) << 16) | (rx_buf[1] << 8) | rx_buf[2];
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// // Sign-extend 22-bit value
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// int32_t value = raw;
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// if (value & (1 << 21)) value |= 0xFFC00000;
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// return value;
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// }
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int32_t mcp3550_read(uint8_t cs_pin)
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{
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uint32_t data = 0;
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int64_t start = esp_timer_get_time();
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uint32_t timeout_us = MCP3550_TIMEOUT_MS * 1000;
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// CS LOW
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mcp23018_set_pin(MCP23018_DEV_HANDLE, cs_pin, 0);
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// Wait for DR (MISO LOW)
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while (gpio_get_level(MCP3550_MISO_GPIO)) {
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if ((esp_timer_get_time() - start) > timeout_us) {
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ESP_LOGW(TAG_MICS, "Timeout waiting for MISO=0 on CS %u", cs_pin);
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mcp23018_set_pin(MCP23018_DEV_HANDLE, cs_pin, 1); // CS HIGH
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return INT32_MIN;
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}
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vTaskDelay(pdMS_TO_TICKS(10)); // Wait 1 tick (e.g., 1ms)
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}
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// Clock out 25 bits
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for (int i = 0; i < 25; i++) {
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gpio_set_level(MCP3550_SCK_GPIO, 1);
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esp_rom_delay_us(5); // small delay to simulate clock high
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data = (data << 1) | gpio_get_level(MCP3550_MISO_GPIO);
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gpio_set_level(MCP3550_SCK_GPIO, 0);
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esp_rom_delay_us(5); // small delay to simulate clock low
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}
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mcp23018_set_pin(MCP23018_DEV_HANDLE, cs_pin, 1); // CS HIGH
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// Extract 22-bit value (bits [23:2])
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uint32_t raw = (data >> 2) & 0x3FFFFF;
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// Sign-extend 22-bit value
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int32_t value = raw;
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if (value & (1 << 21)) value |= 0xFFC00000;
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return value;
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}
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float mcp3550_to_voltage(int32_t value, float vref)
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{
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return ((float)value / (1 << 21)) * vref;
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}
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mics_adc_data_t mcp3550_read_all(float vref)
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{
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mics_adc_data_t data;
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int32_t raw[ADC_COUNT];
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float volts[ADC_COUNT];
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for (int i = 0; i < ADC_COUNT; i++) {
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raw[i] = mcp3550_read(adc_cs_pins[i]);
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vTaskDelay(pdMS_TO_TICKS(10)); // Wait before retrying
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volts[i] = mcp3550_to_voltage(raw[i], vref);
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}
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data.raw_nh3 = raw[0]; data.volts_nh3 = volts[0];
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data.raw_co = raw[1]; data.volts_co = volts[1];
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data.raw_no2 = raw[2]; data.volts_no2 = volts[2];
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data.raw_uvc = raw[3]; data.volts_uvc = volts[3];
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return data;
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}
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void log_mics_adc_values(mics_adc_data_t *data)
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{
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ESP_LOGI(TAG_MICS,
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"ADC Readings:\n"
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" NH3 -> Raw: %ld, Voltage: %f V\n"
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" CO -> Raw: %ld, Voltage: %f V\n"
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" NO2 -> Raw: %ld, Voltage: %f V\n"
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" UVC -> Raw: %ld, Voltage: %f V",
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data->raw_nh3, data->volts_nh3,
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data->raw_co, data->volts_co,
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data->raw_no2, data->volts_no2,
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data->raw_uvc, data->volts_uvc);
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}
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