[参考译文] ADS1220：使用 ADS1220和 STM32H7测量 RTD Pt100 (通过 SPI 连接)

https://e2e.ti.com/support/data-converters-group/data-converters/f/data-converters-forum/1362529/ads1220-measure-of-rtd-pt100-with-ads1220-and-stm32h7-over-spi-connexion

尊敬的 TI、尊敬的 Angel Rodriguez、

我们正在测试我在上一个问题[1]中提到的电路板 、以通过 RTD 3线 Pt100传感器使用 ADS1220测量精确温度。

1.原理图
在验证了 EVB 和连接到 Arduino MCU 的 cjmcu-1220后、我们使用此原理图。
ADS1220连接到 SPI 总线和 STM32H7 MCU、用于 MOSI/MISO/CK 和 CS/DRDY 通过 GPIO 扩展器连接。


GPIO 扩展器工作正常、我们可以通过配置寄存器的 SPI 与 ADS1220进行通信、并读取输出代码、不过接收到的数据似乎不正确、但硬件连接似乎正常工作

SPI 通信
SPI 线路上的探测似乎正确
D4=、D5=MISO、D6=MOSI、D7=CS


我们可以观察到传入的 MISO 数据、


软件配置
我们目前正在使用以下代码

#include <Adafruit_MCP23X17.h>
#include <Protocentral_ADS1220.h>
#include <SPI.h>
#include <atomic>

Adafruit_MCP23X17 mcp;

#define PGA          32                // Programmable Gain, confirm that the same as set_pga_gain
#define VREF         2.048            // Internal reference of 2.048V
#define VFSR         VREF/PGA
#define FULL_SCALE   (((long int)1<<23)-1)

#define ADS1220_CS_PIN    PIN_SPI_SS
#define ADS1220_DRDY_PIN  2

// #define NUM_ADS1220 8
#define NUM_ADS1220 1

SPISettings spi_settings(1000000, MSBFIRST, SPI_MODE1);
Protocentral_ADS1220 ads1220[NUM_ADS1220];
int32_t adc_data;
float ADS1220Temperature;

void setup()
{
    Serial.begin(115200);
    while (!Serial) ;

    delay(5000);

    Serial.println("Set up MCP23017");

    // if (!mcp.begin_I2C(0x20, &Wire2)) {
    if (!mcp.begin_I2C(0x20, &Wire2)) {
        Serial.println("Failed to initialize MCP23X17 device at 0x20");
    }
    for (size_t i = 0; i < 8; i++) {
        mcp.pinMode(7 - i, INPUT); // 7-0: port A, DRDY, INPUT
        mcp.pinMode(i + 8, OUTPUT); // 8-15: port B, CS, OUTPUT
    }
    for (size_t i = 0; i < 8; i++) {
        mcp.digitalWrite(i + 8, HIGH); // Set CS to HIGH
    }

    Serial.println("Set up ADS1220");

    SPI.begin();
    for (size_t i = 0; i < NUM_ADS1220; i++) {
        ads1220[i] = Protocentral_ADS1220(spi_settings);
        ads1220[i].begin(
            [i] (bool level) { mcp.digitalWrite(i + 8, level); },
            [i] () -> bool { return mcp.digitalRead(7 - i); }
        );

        ads1220[i].set_pga_gain(PGA_GAIN_1);
        ads1220[i].set_data_rate(DR_600SPS);
        ads1220[i].select_mux_channels(MUX_AIN0_AIN1);  //Configure for differential measurement between AIN0 and AIN1
        ads1220[i].set_VREF(VREF_REFP0);
        ads1220[i].set_IDAC_Current(IDAC_250);
        ads1220[i].set_IDAC2_Route(IDAC2_AIN0);
        ads1220[i].set_IDAC1_Route(IDAC1_AIN1);
        ads1220[i].PrintRegisterValues();

        ads1220[i].set_conv_mode_single_shot(); //Set Single shot mode
    }

    Serial.println("Start");
}

void loop()
{
    for (size_t i = 0; i < NUM_ADS1220; i++) {
        adc_data = ads1220[i].Read_SingleShot_WaitForData();
        Serial.print("\n\nADS1220 No.");
        Serial.print(i);
        Serial.print(" Diff (mV): ");
        Serial.print(convertToMilliV(adc_data));
        delay(500);

        // float temperature = readADS1220Temperature(i);
        // Serial.print("\nADS1220 No.");
        // Serial.print(i);
        // Serial.print(" Temperature in °C: ");
        // Serial.print(temperature);
        // delay(100);
    }
    delay(1000);
}

float convertToMilliV(int32_t i32data)
{
    return (float)((i32data*VFSR*1000)/FULL_SCALE);
}

float readADS1220Temperature(size_t i)
{
    ads1220[i].TemperatureSensorMode_enable();
    delay(50); // waiting time after register changed, for 20SPS
    float temperature = (ads1220[i].Read_Data_Samples() / 1000 * 0.03125); // In °C
    ads1220[i].TemperatureSensorMode_disable();
    delay(50); // waiting time after register changed, for 20SPS
    return temperature;
}

我的好！

Zabieru.


[1]: e2e.ti.com/.../ads1220-ads1220-spi-connection-to-stm32h7