将长值打印为带前导零的十六进制

Question

I've been using this function to print int values with leading zeroes with 4 decimals, which has been working well.

Use Arduino IDE 1.8.12

void printHex(int num, int precision)
{
  Serial.println(num);
  char tmp[16];
  char format[128];
  sprintf(format, "%%.%dX", precision);
  sprintf(tmp, format, num);
  Serial.println(tmp);
}

Calling the function printHex(100,4) prints out 0064

I now want to print long values with 5 decimals but its not as simple as I thought.

Eg printHex(200000,5) should print out 30D40 , and printHex(0,5) should print 00000

I tried changing int num to long num and its printing 5 digits, but the MSB is always 0

Currently I'm getting 00D40 instead of 30D40

Answer 1

Figured it out, had to use uint32_t and long in the sprintf

void printHex(uint32_t num, int precision)
{
  char tmp[16];
  char format[128];
  sprintf(format, "%%0%dlX", precision);
  sprintf(tmp, format, num);
  Serial.print(tmp);

}