Can this lib be used on ATTiny85 ?

[sebcaps]

I'd like to use this lib on ATtiny85, but while compiling I've got many errors which seems related to Wire.h lib (see below and here
Arduino: 1.8.10 (Windows 10), Board: "ATtiny25/45/85, ATtiny45, Internal 1 MHz" C:\Users\seb\AppData\Local\Arduino15\packages\arduino\hardware\avr\1.8.2\libraries\Wire\src\utility\twi.c: In function 'twi_init': C:\Users\seb\AppData\Local\Arduino15\packages\arduino\hardware\avr\1.8.2\libraries\Wire\src\utility\twi.c:76:16: error: 'SDA' undeclared (first use in this function) digitalWrite(SDA, 1);^~~C:\Users\seb\AppData\Local\Arduino15\packages\arduino\hardware\avr\1.8.2\libraries\Wire\src\utility\twi.c:76:16: note: each undeclared identifier is reported only once for each function it appears in C:\Users\seb\AppData\Local\Arduino15\packages\arduino\hardware\avr\1.8.2\libraries\Wire\src\utility\twi.c:77:16: error: 'SCL' undeclared (first use in this function); did you mean 'SPL'? digitalWrite(SCL, 1);^~~SPL In file included from c:\users\seb\appdata\local\arduino15\packages\arduino\tools\avr-gcc\7.3.0-atmel3.6.1-arduino5\avr\include\avr\io.h:99:0, from C:\Users\seb\AppData\Local\Arduino15\packages\arduino\hardware\avr\1.8.2\libraries\Wire\src\utility\twi.c:25:C:\Users\seb\AppData\Local\Arduino15\packages\arduino\hardware\avr\1.8.2\libraries\Wire\src\utility\twi.c:80:7: error: 'TWSR' undeclared (first use in this function); did you mean 'ACSR'? cbi(TWSR, TWPS0);

I tried to replace Wire lib with TinyWire with no more success.

Any help appreciated !
Thx

[pwm84]

In Adafruit MCP23017.h, change lines 17-22 as follows:

// Don't forget the Wire library
//#ifdef AVR_ATtiny85 //TinyWireM is now part of
#include <TinyWireM.h> // Adafruit version of Wire Library
//#else
//#include <Wire.h>
//#endif

[dertobias]

also you have to add those lines
after including TinyWireM.h
#define Wire TinyWireM
#define TwoWire USI_TWI

https://forum.arduino.cc/index.php?topic=656742.0

….and don't forget external pull-ups for scl & sda 😅

[caternuson]

Yep, it should work as long as you can get an I2C library to build for the tiny. Fixing #63 should help with this also, since it will allow whatever I2C bus to be passed in, either Wire or TinyWire based.