tinySPI | Arduino hardware SPI library for ATtiny44/84

tinySPI is a C++ library typically used in Internet of Things (IoT), Arduino applications. tinySPI has no bugs, it has no vulnerabilities, it has a Strong Copyleft License and it has low support. You can download it from GitHub.

tinySPI is an Arduino SPI master library for ATtiny microcontrollers that utilizes the USI hardware in the ATtiny MCUs. Supported MCUs include ATtiny24/44/84, 25/45/85, 261/461/861, 2313/4313. Because the USI hardware is not as sophisticated as the dedicated SPI hardware in the ATmega MCUs, tinySPI is more limited than the standard Arduino SPI library but still has several advantages over software bit-bang approaches. As compared to the Arduino shiftOut() function, tinySPI. tinySPI does not support. tinySPI will generate an SPI bit clock that is about one-tenth the MCU system clock frequency. For example, given a 1MHz system clock, the SPI clock will be about 100kHz, and it will take about 80μs to transfer one byte. Interrupts are inhibited during each byte transfer to ensure a consistent bit clock period. Included with the library are example sketches that demonstrate driving a 74HC595 shift register from an ATtiny84 and from an ATtiny85. tinySPI has been tested with Arduino 1.8.5 and the ATTiny Core.