I am trying to control two stepper motors using arduino uno and 2 x-nucleo-ihm03a1, driver stacked on bottom motor working fine but top driver not responding
R3 and R6 closed, R4,R5,R7,R8 open for first board,
for second board R4 and R8 closed , R3,R5,R6,R7 open for second board( TOP BOARD)

#include <Ponoor_PowerSTEP01Library.h>
#include <SPI.h>

// Pin definitions for the X-NUCLEO-IHM03A1 connected to an Uno-compatible board
#define nCS_PIN 10
#define nCS_PIN2 9

#define nSTBY_nRESET_PIN 8
#define nBUSY_PIN 6
#define nSTBY_nRESET_PIN2 7
#define nBUSY_PIN2 5

powerSTEP driver(1, nCS_PIN, nSTBY_nRESET_PIN);
powerSTEP driver2(0, nCS_PIN2, nSTBY_nRESET_PIN2);

void setup()
{
  // Start serial
  Serial.begin(9600);
  Serial.println("powerSTEP01 Arduino control initialising...");

  // Prepare pins
  pinMode(nSTBY_nRESET_PIN, OUTPUT);
  pinMode(nSTBY_nRESET_PIN2, OUTPUT);
  pinMode(nBUSY_PIN, OUTPUT);
  pinMode(nBUSY_PIN2, OUTPUT);
  pinMode(nCS_PIN, OUTPUT);
  pinMode(nCS_PIN2, OUTPUT);
  pinMode(MOSI, OUTPUT);
  pinMode(MISO, OUTPUT);
  pinMode(SCK, OUTPUT);

  // Reset powerSTEP and set CS
  digitalWrite(nSTBY_nRESET_PIN, HIGH);
  delay(1);
  digitalWrite(nSTBY_nRESET_PIN, LOW);
  delay(1);
  digitalWrite(nSTBY_nRESET_PIN, HIGH);

  digitalWrite(nSTBY_nRESET_PIN2, HIGH);
  delay(1);
  digitalWrite(nSTBY_nRESET_PIN2, LOW);
  delay(1);
  digitalWrite(nSTBY_nRESET_PIN2, HIGH);

  digitalWrite(nCS_PIN, HIGH);
  digitalWrite(nCS_PIN2, HIGH);

  SPI.begin();
  SPI.setDataMode(SPI_MODE3);

  // Configure powerSTEP for driver 1
  selectDriver1();
  driver.SPIPortConnect(&SPI);
  driver.configSyncPin(nBUSY_PIN, 0);
  driver.configStepMode(STEP_FS_8);
  driver.setMaxSpeed(1000);
  driver.setFullSpeed(2000);
  driver.setAcc(2000);
  driver.setDec(2000);
  driver.setSlewRate(SR_520V_us);
  driver.setOCThreshold(2);
  driver.setOCShutdown(OC_SD_ENABLE);
  driver.setPWMFreq(PWM_DIV_4, PWM_MUL_0_75);
  driver.setVoltageComp(VS_COMP_DISABLE);
  driver.setSwitchMode(SW_USER);
  driver.setOscMode(INT_16MHZ);
  driver.setRunKVAL(64);
  driver.setAccKVAL(64);
  driver.setDecKVAL(64);
  driver.setHoldKVAL(8);
  driver.setParam(ALARM_EN, 0x8F);
  driver.getStatus();
  deselectDriver1();

  // Configure powerSTEP for driver 2
  selectDriver2();
  driver2.SPIPortConnect(&SPI);
  driver2.configSyncPin(nBUSY_PIN2, 1);
  driver2.configStepMode(STEP_FS_8);
  driver2.setMaxSpeed(500);
  driver2.setFullSpeed(1000);
  driver2.setAcc(1000);
  driver2.setDec(1000);
  driver2.setSlewRate(SR_114V_us);
  driver2.setOCThreshold(8);
  driver2.setOCShutdown(OC_SD_ENABLE);
  driver2.setPWMFreq(PWM_DIV_4, PWM_MUL_0_75);
  driver2.setVoltageComp(VS_COMP_DISABLE);
  driver2.setSwitchMode(SW_USER);
  driver2.setOscMode(INT_16MHZ);
  driver2.setRunKVAL(20);
  driver2.setAccKVAL(20);
  driver2.setDecKVAL(20);
  driver2.setHoldKVAL(4);
  driver2.setParam(ALARM_EN, 0x8F);
  driver2.getStatus();
  deselectDriver2();

  Serial.println(F("Initialisation complete"));
}

void selectDriver1() {
  digitalWrite(nCS_PIN, LOW);
  digitalWrite(nCS_PIN2, HIGH);
}

void deselectDriver1() {
  digitalWrite(nCS_PIN, HIGH);
}

void selectDriver2() {
  digitalWrite(nCS_PIN, HIGH);
  digitalWrite(nCS_PIN2, LOW);
}

void deselectDriver2() {
  digitalWrite(nCS_PIN2, HIGH);
}

void loop() {
  if (Serial.available() > 0) {
    char command = Serial.read();
    if (command == 'F') {
      Serial.println("Forward");
      selectDriver1();
      driver.run(FWD, 1200);
      deselectDriver1();
      
      selectDriver2();
      driver2.run(FWD, 2000);
      deselectDriver2();
    } else if (command == 'B') {
      Serial.println("Backward");
      selectDriver1();
      driver.run(REV, 600);
      deselectDriver1();

      selectDriver2();
      driver2.run(REV, 600);
      deselectDriver2();
    } else if (command == 'S') {
      Serial.println("Stop");
      selectDriver1();
      driver.softStop();
      deselectDriver1();

      selectDriver2();
      driver2.softStop();
      deselectDriver2();
    }

    // Additional debugging
    selectDriver1();
    Serial.print("Driver1 Status: ");
    Serial.println(driver.getStatus(), HEX);
    deselectDriver1();

    selectDriver2();
    Serial.print("Driver2 Status: ");
    Serial.println(driver2.getStatus(), HEX);
    deselectDriver2();
  }
}

• I tried each board with 1 motor and it worked fine
• I tried to change resistors R3-R8 combination
• I checked all connections using AVO