//https://forum.arduino.cc/t/how-to-connect-two-half-bytes/1377477/23?

const char *hexIn = "8F C1 FF FF 5D";
const char del[] = " ";
char * endptr, * myPtr;
char hex2dec[10];
uint32_t dec = 0;

void nextHex() {

  if (myPtr != NULL) {
    dec = strtol(myPtr, &endptr, 16);
    sprintf(hex2dec,"%s %d", myPtr, dec);
    Serial.println(hex2dec);
    myPtr = strtok(NULL, del);
  }
}

 void setup() {
  Serial.begin(115200);
  Serial.println("Hi");
  myPtr = strtok(hexIn, del);
}

void loop() {
  delay(1000);
  nextHex();
}