C8051F580 printf question

I am working with the C8051F580 MCU.

using my own hardware.

The board is connected to teraterm via UART0

8bits, 115200

I am trying to print a hex number, see very simple code below.

for some reason I always get two extra "zeros" added at the end.

#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <stdarg.h>
#include <float.h>
#include <stdlib.h>
//#include <math.h>
#include <c8051f58x.h>
#include "C8051F580_defs.h"
#include "compiler_defs.h"
#include "PUTCHAR.c"

unsigned char i;

i = 0x12;
printf("i = 0x%02Xh", i);

terminal shows:

i = 0x1200h <== two extra zeros, it does not matter if I add the (char) casting before "i" in the print expression.

Any suggestion will be appreciated

Thank you

Fausto Bartra

Parents
  • Do you really need printf?  That function is a burden on an 8051. My recommendations would be to use the SiLabs debugger or just create a very simple function to convert a hex byte to ASCII.

    Edit: I see you are also using floats. Again if this can be avoided using things like fractional equivalents (integers), then that would be worth considering. The SILabs 8051's are a marvel, but it's an odd choice for someone who expects to use printf() and floats.

Reply
  • Do you really need printf?  That function is a burden on an 8051. My recommendations would be to use the SiLabs debugger or just create a very simple function to convert a hex byte to ASCII.

    Edit: I see you are also using floats. Again if this can be avoided using things like fractional equivalents (integers), then that would be worth considering. The SILabs 8051's are a marvel, but it's an odd choice for someone who expects to use printf() and floats.

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