I am using eval STPM34 for energy meter project. I am connecting ESP32 to STPM34 using UART. i.e. only Tx and Rx are used. I am writing ESP32 code using Arduino IDE. I cannot read any other register data

[Rbhiv.2076]

I am using eval STPM34 for energy meter project. I am connecting ESP32 to STPM34 using UART. i.e. only Tx and Rx are used.

I am writing ESP32 code using Arduino IDE.

When I use Serial2.read() function to read any register data, I always get "160 0 0 4" i.e. "A0 00 00 04"... These are contents of 0x00 register..

I can not read any other register, evenif I give right address.

Code is given below for immediate reference :-

(Note: using SPI, i am able to read all register, but using UART, I failed)

#define RXD2 16

#define TXD2 17

#define SYN    5  // SYN pin

#define CS     18   // Chip select pin

#define READ_DELAY 500  // delay after reading. value in MS

byte tabByte[4];

static long total;

int cnt;

void ActiveSync() {

 /* digitalWrite(SYN, LOW);

 delayMicroseconds(4);           // waits for a 1 millisecond

 digitalWrite(SYN, HIGH);

 delay(1); */

}

//READING FROM STPM

void sendBufferContent(){

 //knowing that it returns the LSByte first

 Serial.println("Reading registers");

 if(Serial2.available())

 {

  // while(Serial2.available() > 0 ) {

       for (int i=0;i<4;i++){

         tabByte[i]=Serial2.read();

         Serial.println(tabByte[i]);

       }

        while(Serial2.available() > 0 ) {

         Serial2.read();

       }

    //}

    delay(READ_DELAY);

 }

 else{

    Serial.println("NOT READING");

 }

}

/*

 format :

 <Read Address><Write Address><bit[7-0]><bit[15-8]>

 */

void UART_Send_Data(int One, int Two, int Three, int Four) {

 Serial2.write(One);

 Serial2.write(Two);

 Serial2.write(Three);

 Serial2.write(Four);

 //Serial2.write(0xFF);

 // Serial2.write(0xff);

 delay(READ_DELAY);

}

/*

 DSCR: Making SPI con reg 2 to skip CRC check and rest values are default

 0xFF : Read nothing

 0x24 : Select SPI Control register 1 address lower word

 0x25 : Select SPI Control register 1 address higher word

*/

void configUS_REG1(){

 UART_Send_Data(0xFF, 0x24, 0x00, 0x00);

 UART_Send_Data(0xFF, 0x25, 0x00, 0x00);

 delay(100);

}

/*

 DSCR : Making SPI con reg 1 to set baud 115200 and rest values are default

 0xFF : Read nothing

 0x26 : Select SPI Control register 2 address lower word

 0x27 : Select SPI Control register 2 address higher word

 0x8B : Baud rate is 115200

*/

void configUS_REG2(){

 //UART_Send_Data(0xFF, 0x26, 0x8B, 0x00);

 UART_Send_Data(0xFF, 0x26, 0x83, 0x06);

 UART_Send_Data(0xFF, 0x27, 0x00, 0x00);

 delay(100);

}

/*

 DSCR : Configuration _ Reg DSP_CR3

 0x04 : Read nothing

 0x05 : Write in DSP CR3 higher word

 0xE0 : Autolatch every 128 milli secs (at 7.8125khz)

 0x44 : Remaining are default values

 0x81 : Autolatch every 128 milli secs (at 7.8125khz)

*/

void configDSP_CR3(){

 UART_Send_Data(0x04, 0x05, 0xE0, 0x44);

 delay(100);

 UART_Send_Data(0x05, 0x05, 0x81, 0x00);

 delay(100);

}

void STPMReset(){

 UART_Send_Data(0x05, 0x05, 0x00, 0x10);

 /* Clearing all status resisters */

 UART_Send_Data(0x20, 0x20, 0x00, 0x00);

 UART_Send_Data(0x21, 0x21, 0x00, 0x00);

 UART_Send_Data(0x22, 0x22, 0x00, 0x00);

 UART_Send_Data(0x23, 0x23, 0x00, 0x00);

 delay(100);

}

/*

 DSCR : Configuration _ Reg DSP_CR1

 0x00 : write in DSP CR1 lower word

 0xA0 : internal reference enabled, default temperature compensation

*/

void configDSP_CR1(){

 UART_Send_Data(0x00, 0x00, 0xA0, 0x00);

 delay(100);

}

/*

 DSCR : Configuration _ Reg DFE_CR1

 0x18 : write in DFE_CR1 lower word

 0x27 :

 0x03 :

*/

void configDFE_CR1() {

  UART_Send_Data(0x18, 0x00, 0x27, 0x03);

  delay(100);

  UART_Send_Data(0x19, 0x00, 0x27, 0x03);

  delay(100);

}

/*

 addr : Active register address

 0xFF : Write nothing 

*/

void readReg(int addr){

 Serial.print("cnt = ");

 Serial.println(cnt);

 cnt++;

 Serial.print("addess = ");

 Serial.println(addr);

  UART_Send_Data(addr, 0xFF, 0xFF, 0xFF);

  delay(1000);

  //MISO sends answer in next time frame

  sendBufferContent();//reading now

ActiveSync();

 addr += 2;

 Serial.print("cnt = ");

 Serial.println(cnt);

 cnt++;

 Serial.print("addess = ");

 Serial.println(addr);

  UART_Send_Data(addr, 0xFF, 0xFF, 0xFF);

  delay(1000);

  //MISO sends answer in next time frame

  sendBufferContent();//reading now

  ActiveSync();

}

/* Init STPM34 */

void STPMInitReset() {

 pinMode(SYN, OUTPUT);   // sets the digital pin SYN as output

 pinMode(CS, OUTPUT);   // sets the digital pin SYN as output

 digitalWrite(SYN, LOW);

 delay(1);           // waits for a 1 millisecond

 digitalWrite(SYN, HIGH); 

 delay(1);           // waits for a 1 millisecond

 digitalWrite(SYN, LOW);

 delay(1);           // waits for a 1 millisecond

 digitalWrite(SYN, HIGH); 

 delay(1);           // waits for a 1 millisecond

 digitalWrite(SYN, LOW);

 delay(1);           // waits for a 1 millisecond

 digitalWrite(SYN, HIGH); 

 delay(1);           // waits for a 1 millisecond

 digitalWrite(CS, LOW);

 delay(1);           // waits for a 1 millisecond

 digitalWrite(CS, HIGH); 

 delay(1);           // waits for a 1 millisecond

}

/* SETUP */

void setup() {

 Serial.begin(115200);

 Serial.println("Starting code 2");

 Serial2.begin(9600, SERIAL_8N1, RXD2, TXD2);

 cnt = 0;

 // Reset STPM

 STPMInitReset();

 STPMReset();

 /* Do register settings */

 configUS_REG1(); // US_REG1

 configUS_REG2(); // US_REG2

 configDSP_CR1(); // DSP_CR1

 configDSP_CR3(); // DSP_CR3

 configDFE_CR1(); // DFE_CR1 = 0x03270327

 // Delay before reading current register

 delay(3000);

}

//SPI CONFIG AND DATA TRANSFER

void loop() {

 static int ad = 0;

 ad += 2;

 readReg(ad);

 delay(1000); // add delay of 10 minutes

}

[OKORK.1]

It is about to be 2 months over you asked the question. I don't know did you find an answer. I was looking for a solution to this situation because I am getting the same bytes from STPM.

But you are making some obvious mistakes:

1) You are not making a communication peripheral selection (SPI or UART). When first energizing the IC you must do the selection. Look to the STPMx Getting Started documentation.

2) You are not sending the CRC byte which is default enabled. Again look to the STPMx Getting Started documentation.

In the STPMx Getting Started document page 14 it says that:

"Note that even if CRC received from the host is wrong, the answer of the STMP3x is in any

case the default value of the 1st register (0x040000A0). Then, an interruption can be

enabled to activate a wrong CRC detection (see datasheet for details)."

I know all the above data but I am still getting (0x040000A0) bytes 🙂 I am working on it.