Attiny Serial Out

Available as Arduino library "ATtinySerialOut"

Version 2.1.1 - work in progress

Minimal bit-bang send serial

115200 baud for 1/8/16 MHz ATtiny clock.

Perfect for debugging purposes.

Provides Serial.print / println functions for easy software porting.

Code size is only 76 bytes@38400 baud or 196 bytes@115200 baud (including first call).

Provides additional fast printHex() and printlnHex() functions.

Default TX pin is PB2 on a ATtiny85.

Using the new *.hpp files / how to avoid multiple definitions linker errors

In order to support compile options more easily, the line #include <ATtinySerialOut.h> must be changed to #include <ATtinySerialOut.hpp>, but only in your main program (.ino file), like it is done in the examples.
In all other files you must use #include <ATtinySerialOut.h>, otherwise you will get tons of "multiple definition" errors.

(.text+0x0): multiple definition of `initTXPin()'
.\ShowInfo.cpp.o (symbol from plugin):(.text+0x0): first defined here

To fix the error, you must rename the include directive in the file mentioned in the error (here: ShowInfo.cpp) from #include "ATtinySerialOut.hpp" to #include "ATtinySerialOut.h".

Compile options / macros for this library

To customize the library to different requirements, there are some compile options / macros available.
These macros must be defined in your program before the line #include <TinySerialOut.hpp> to take effect.
Modify them by enabling / disabling them, or change the values if applicable.

Changing include (*.h) files with Arduino IDE

First, use Sketch > Show Sketch Folder (Ctrl+K).
If you have not yet saved the example as your own sketch, then you are instantly in the right library folder.
Otherwise you have to navigate to the parallel libraries folder and select the library you want to access.
In both cases the library source and include files are located in the libraries src directory.
The modification must be renewed for each new library version!

Modifying compile options / macros with PlatformIO

If you are using PlatformIO, you can define the macros in the platformio.ini file with build_flags = -D MACRO_NAME or build_flags = -D MACRO_NAME=macroValue.

Modifying compile options / macros with Sloeber IDE

If you are using Sloeber as your IDE, you can easily define global symbols with Properties > Arduino > CompileOptions.

Serial functions provided (linefeed is \n instead of \r\n):

    void print(const __FlashStringHelper *aStringPtr);
    void print(const char *aStringPtr);
    void print(char aChar);
    void print(uint8_t aByte, uint8_t aBase = 10);
    void print(int16_t, uint8_t aBase = 10);
    void print(uint16_t aInteger, uint8_t aBase = 10);
    void print(uint32_t aLong, uint8_t aBase = 10);
    void print(uint32_t aLong, uint8_t aBase = 10);
    void print(double aFloat, uint8_t aDigits = 2);

    void printHex(uint8_t aByte); // with 0x prefix

    void println(const __FlashStringHelper *aStringPtr);
    void println(char aChar);
    void println(uint8_t aByte, uint8_t aBase = 10);
    void println(int16_t aInteger, uint8_t aBase = 10);
    void println(uint16_t aInteger, uint8_t aBase = 10);
    void println(int32_t aLong, uint8_t aBase = 10);
    void println(uint32_t aLong, uint8_t aBase = 10);
    void println(double aFloat, uint8_t aDigits = 2);

    void println(void);

Error call of overloaded 'println(fstr_t*)' is ambiguous.

Please use the new Digistump core. Since version 1.2.0, the library is no longer compatible with the old cores supplied by digistump.

OpenWindowAlarm example

This example issues an alarm if the chip sensor detect a falling teperarure and is fully documented here

Revision History

Version 2.1.1 - work in progress

Version 2.1.0 - work in progress

• Added compile guard.
• Added USE_PORTB_FOR_TX_PIN to allow TX pin on port B for ATtiny87/167.
• Improved #if guard for instance naming.

Version 2.0.0 - 09/2021

• Renamed ATtinySerialOut.cpp to ATtinySerialOut.hpp => TX pin can be defined in main program.
• Added symbol TINY_SERIAL_INHERIT_FROM_PRINT - if defined, you can use this class as a replacement for standard Serial as a print class.

Version 1.2.2 - 03/2021

• Cloned ATtinySerialOut.cpp as ATtinySerialOut.hpp for direct include.
• Added ATtiny88 support.

Version 1.2.1 - 10/2020

• Added ATtinyX4 support.

Version 1.2.0 - 7/2020

• Removed workaround #define __FlashStringHelper fstr_t for old Digispark core < 1.6.8 in order to work with core >= 1.7.0.
• Added ATtiny167 support.
• Moved functions from h to cpp file.

Version 1.1.0 - 5/2020

• Removed symbol TINY_SERIAL_INHERIT_FROM_PRINT and replaced by macro #define Print TinySerialOut
• Changed int to int16_t and long to int32_t.
• Use utoa() and ultoa() for uint16_t and uint32_t.

Version 1.0.5 - 3/2020

• Added function writeCRLF()

Version 1.0.4 - 1/2020

• Symbol TINY_SERIAL_INHERIT_FROM_PRINT - if defined, you can use this class as a replacement for standard Serial as a print class.
• Improved all ...Hex() functions.
• Define FlashStringHelper for digispark.
• Changed label loop to txloop in write1Start8Data1StopNoParity() for 38400 baud.

Version 1.0.3

• OpenWindowAlarm example updated.

Version 1.0.2

• printHex() now using capital letters.
• Improved OpenWindowAlarm example.

Version 1.0.1

• Renamed example to be consistent.

Version 1.0.0

Initial Arduino library version.

Remark

C version of serial code is included for better understanding, but assembler version is used. This is because for the C code the timing depends on compiler optimisation switches. You should get the right timing if you compile the C code it with Arduino standard settings or:

avr-g++ -I"C:\arduino\hardware\arduino\avr\cores\arduino" -I"C:\arduino\hardware\arduino\avr\variants\standard" -c -g -w -Os -ffunction-sections -fdata-sections -mmcu=attiny85 -DF_CPU=1000000UL -MMD -o "TinySerialOut.o" "TinySerialOut.cpp"

If you find this library useful, please give it a star.