使用ADS1120模数转换芯片接三线的PT1000,但是读出的数据值一直为0x7FFF(32767),请大神看看怎么回事,谢谢。
ADS1120的通讯看过波形是正常的,ADS1120能连续转换数值,所以SPI通讯应该没有问题。
试过将R REF参考电阻换成4.7K等,数值有变成65317的,没正常过。。。
ADS1120软件配置如下:
InputMux = ADS1120_MUX_AIN1_AIN0;
GainLevel = ADS1120_GAIN_16;
PGABypass = ADS1120_USE_PGA;
DataRate = ADS1120_DATA_RATE_20SPS;
OperatingMode = ADS1120_OP_MODE_NORMAL;
ConversionMode = ADS1120_CONVERSION_CONTINUOUS;
IDACCurrent = ADS1120_IDAC_CURRENT_250_UA;
RouteIDAC1 = ADS1120_IDAC1_AIN2;
RouteIDAC2 = ADS1120_IDAC2_AIN3;
ADS1120_TEMP_SENSOR_OFF + ADS1120_BURN_OUT_CURRENT_OFF
ADS1120_VREF_EXT_REF0_PINS + ADS1120_FIR_50_60 + ADS1120_LOW_SIDE_POWER_OPEN
ADS1120_DRDY_ON_DRDY_ONLY
电路图如下: