Print Formatting¶
The UART print() function behaves almost identically to the standard C printf() function. This gives a powerful way to format values as strings for output.
Using `%f` or `%lf` requires a special compiler flag to be enabled. See `lib-common/src/uart/log.c` about this, which is enabled when compiling testing programs but not for main programs.
AVR’s printf() doesn’t support printing 64-bit integers.
Here are the format specifiers for common data types:
| Data Type(s) | Format Specifier(s) |
|---|---|
uint8_t, uint16_t |
%u (Unsigned) |
uint32_t |
%lu (Long Unsigned) |
int8_t, int16_t |
%d (Decimal - Signed) |
int32_t |
%ld (Long Decimal - Signed) |
uint8_t, uint16_t, int8_t, int16_t |
%x (Hexadecimal - Lowercase), %X (Hexadecimal - Uppercase) |
uint32_t, int32_t |
%lx (Long Hexadecimal - Lowercase), %lX (Long Hexadecimal - Uppercase) |
float, double |
%f (Float) |
Integer Formatting¶
An example of controlling integer formatting output as hex:
print("0x%02x", value);
// lowercase hex, always with 2 hex digits (zero padded if necessary)
// add "0x" at the beginning to indicate to the reader that the output is in hex