scottchiefbaker / arduino-printf

Add printf support to the Arduino SDK

Arduino Printf

This library adds support for the printf() function to Arduino projects. This code leverages the wonderful mpaland/printf library, which is designed for use in embedded systems. For more information about what is available, please refer to the parent library documentation.

What This Library Provides

This library provides a standalone implementation for the following functions:

• printf()
• sprintf() and snprintf()
• vprintf() and vsnprintf()

Project Target

This library aims to offer a complete printf() solution while maintaining low storage and RAM requirements. This is critical for MCUs with limited storage and RAM. This project is ideal for AVR based MCUs like the Arduino Uno and it's siblings.

ESP8266 and ESP32

The Arduino implementations for the ESP8266 and ESP32 already include a printf() implementation as part of the base library. Using this library on those platforms would most likely be redundant.

Using the Library

To use this library in your Arduino project, you need to include the header:

#include <LibPrintf.h>

void setup() {
    serial.begin(115200);
}

By default, the library can be used without any special initialization. Any printf() calls will be output using the Arduino Serial interface.

Advanced Usage

See advanced_usage.md.

Disabling Specific Formats

If memory footprint is critical, floating point, exponential, and 'long long' support and can be turned off via the PRINTF_DISABLE_SUPPORT_FLOAT, PRINTF_DISABLE_SUPPORT_EXPONENTIAL and PRINTF_DISABLE_SUPPORT_LONG_LONG compiler switches. You must define these symbols in the build system.

Examples

Multiple examples are provided with this library in the examples/ folder.

• Default Usage
  • Without any initialization, Serial will be the default output for printf()
  • This example initializes the Serial class and prints in a loop
• Specify Print Class
  • Any class derived from the Print base class can be used with the Arduino Printf library
  • This example initializes printf with Serial1 instead of Serial
• Override Putchar
  • This example overrides _putchar() and adds a space in between every letter
  • You can implement any kind of logic within _putchar() that you like, such as outputting information to multiple ports