【Follow me第二季第1期】补充：AD5270数字电位器的驱动应用

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【Follow me第二季第1期】补充：AD5270数字电位器的驱动应用 [复制链接]

 

AD5270是1024位、变阻器模式下的温度系数5 ppm/°C、1%电阻容差误差、SPI接口和50-TP存储器数字变阻器，性能十分优秀。

它集业界领先的可变电阻性能与非易失性存储器(NVM)于一体，并提供50次可编程(50-TP)存储器。将电阻值编程写入50-TP存储器之前，可进行无限次调整。这些器件不需要任何外部电压源来帮助熔断熔丝，并提供50次永久编程的机会。在50-TP激活期间，一个永久熔断熔丝指令会将游标位置固定。SPI接口控制时序如下：

使用开发板的SPI接口（任意IO软件模拟SPI）可以完成驱动控制，测试代码如下：

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// AD5270 commands - new digital potentiometer
#define CMD_WR_RDAC        0x01
#define CMD_RD_RDAC        0x02
#define CMD_ST_RDAC        0x03
#define CMD_RST            0x04
#define CMD_RD_MEM         0x05
#define CMD_RD_ADDR        0x06
#define CMD_WR_CTRL        0x07
#define CMD_RD_CTRL        0x08
#define CMD_SHTDN          0x09

void vspi_write_word(const int chip_select, uint16_t data_to_send, const uint8_t bit_order, const uint8_t mode) {
  vspi->beginTransaction(SPISettings(SPI_FREQ_FAST, bit_order, mode));
  digitalWrite(chip_select, LOW);   //pull SS slow to prep other end for transfer
  vspi->transfer16(data_to_send);
  digitalWrite(chip_select, HIGH);  //pull ss high to signify end of data transfer
  vspi->endTransaction();
}

/* Write a 4-bit command and a 10-bit data word */
void AD5270_Write(const int chip_select, uint8_t cmd, uint16_t data){
  uint16_t data_word = ((cmd & 0x0F) << 10) | (data & 0x03FF);
  vspi_write_word(chip_select, data_word, MSBFIRST, SPI_MODE1);
}

/* Enable/disable rheostat value changes */
void AD5270_LockUnlock(const int chip_select, uint8_t lock){
  AD5270_Write(chip_select, CMD_WR_CTRL, lock ? 0 : 0x002);
}

/* Enable/disable hardware shutdown */
void AD5270_Shutdown(const int chip_select, uint8_t shutdown){
  AD5270_Write(chip_select, CMD_SHTDN, shutdown ? 1 : 0);
}

/* Set the value of the digital rheostat - range is 0-0x3FF (0-100kOhm) */
void AD5270_Set(const int chip_select, uint16_t val)
{
  AD5270_Write(chip_select, CMD_WR_RDAC, val);
}

#define CHIP_SEL_MEAS      10   // Chip select pin for measuring digital rheostat potentiometer

void setup() {
  // put your setup code here, to run once:
      // Set voltage measurement gain to 1 (maximum current (5V pk-pk) must be within ADC range)
    AD5270_Shutdown(CHIP_SEL_MEAS, 1);
  AD5270_Set(CHIP_SEL_MEAS, 100);

}

void loop() {
  // put your main code here, to run repeatedly:

}

测试接线和效果：