Minimal bit-bang send serial 38400/115200 baud for 1MHz or 115200/230400 baud for 8 or 16MHz ATtiny clock
GPL-3.0 License
Minimal bit-bang send serial. 115200 baud for 1/8/16 MHz ATtiny clock.
Available as Arduino library "ATtinySerialOut".
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);
#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() {
}
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()`.
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.
Name | Default value | Description |
---|---|---|
TX_PIN |
PIN_PB2 (PIN_PA1 for ATtiny87/167) | The pin to use for transmitting bit bang serial. These pin names are valid for ATTinyCore and may be different in other cores. |
TINY_SERIAL_DO_NOT_USE_115200BAUD |
disabled | To force using other baud rates. The rates are 38400 baud at 1 MHz (which has smaller code size) or 230400 baud at 8/16 MHz. |
TINY_SERIAL_INHERIT_FROM_PRINT |
disabled | If defined, you can use this class as a replacement for standard Serial as a print class e.g. for functions like void prinInfo(Print *aSerial) . Increases program size. |
This example issues an alarm if the chip sensor detect a falling teperarure and is fully documented here
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.
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.
USE_PORTB_FOR_TX_PIN
.USE_PORTB_FOR_TX_PIN
to allow TX pin on port B for ATtiny87/167.TINY_SERIAL_INHERIT_FROM_PRINT
- if defined, you can use this class as a replacement for standard Serial as a print class.#define __FlashStringHelper fstr_t
for old Digispark core < 1.6.8 in order to work with core >= 1.7.0.TINY_SERIAL_INHERIT_FROM_PRINT
and replaced by macro #define Print TinySerialOut
int
to int16_t
and long
to int32_t
.utoa()
and ultoa()
for uint16_t
and uint32_t
.writeCRLF()
loop
to txloop
in write1Start8Data1StopNoParity()
for 38400 baud.printHex()
now using capital letters.Initial Arduino library version.
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"