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Attiny Serial Out

Minimal bit-bang send serial. 115200 baud for 1/8/16 MHz ATtiny clock.<br/>

                <br/> <br/>

Available as Arduino library "ATtinySerialOut".

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Features

• 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 PIN_PB2 on an ATtiny85.

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);

Example

#include <Arduino.h>

#if defined(__AVR_ATtiny87__) || defined(__AVR_ATtiny167__)
#define TX_PIN PIN_PA1 // (package pin 2 / TXD on Tiny167) - can use one of PIN_PA0 to PIN_PA7 here
#else
#define TX_PIN PIN_PB2 // (package pin 7 on Tiny85) - can use one of PIN_PB0 to PIN_PB4 (+PIN_PB5) here
#endif

void setup(void) {
    initTXPin();
    Serial.println(F("START " __FILE__ " from " __DATE__ "\r\nUsing library version " VERSION_ATTINY_SERIAL_OUT));
    writeString("OSCCAL=");
    writeUnsignedByteHexWithPrefix(OSCCAL);
}
void loop() {
}

Using the new *.hpp files

In order to support compile options more easily, the line #include <ATtinySerialOut.h> must be changed to #include <ATtinySerialOut.hpp> in your main program (aka *.ino file with setup() and loop()).

In all other files you must use #include <ATtinySerialOut.h>, to prevent multiple definitions linker errors:

If you forget to include ATtinySerialOut.hpp, you will see errors like ATtinySerialOutExample.cpp:38: undefined reference to initTXPin()`.

Compile options / macros for this library

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

OpenWindowAlarm example

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

Troubleshooting

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.

Error type 'TinySerialOut' is not a base type for type 'TwoWire' using Print::write;

Reason: Another class, e.g. ATTinyCore class TwoWire : public Stream uses the Print class or a Print method, but Print is normally redefined by ATtinySerialOut. You must define TINY_SERIAL_INHERIT_FROM_PRINT before including ATtinySerialOut.hpp, to avoid this error.

Revision History

Version 2.3.0

• Support of all ports of ATtiny88 using ATTinyCore numbering scheme.

Version 2.2.1

• Usage of ATTinyCore pin numbering also for ATtiny167.

Version 2.2.0

• Usage of ATTinyCore pin numbering scheme e.g. PIN_PB2 and therefore removed USE_PORTB_FOR_TX_PIN.

Version 2.1.1

• Adjusted macro for MH-ET LIVE Core.

Version 2.1.0

• 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"