remove SPI class for ATTiny: provided by ATTinyCore

[jscrane]

This patch removes the custom SPI class for ATTiny. (Seems fitting because it was my code originally.)

(Addresses issue #572)

Tested on my Tinysensor ATTiny84-based board: https://github.com/jscrane/TinySensors/tree/master/tinysensor

[2bndy5]

Ok @jscrane you obviously did your part (can't think of better person for the task). Now I have to do my part. I'll wire up a 3V regulator and test this on my digispark (ATTiny85).

[2bndy5]

OK, this will compile for the ATTiny85, but not for the DigiSpark. In the Arduino IDE I selected the DigiSpark (non-Pro) and I get the same errors reported in #226. Using PlatformIO, I specified the digispark-tiny board, and I get the same errors again. However, using PlatformIO, I changed the board type to attiny85 and it compiles fine.

I understand that the errors from #226 are more specific to the DigiSpark core (I don't think its been updated in a long time). I'm wondering if we should make a note of this in the docs somewhere.

[2bndy5]

I may have prematurely merged this. @jscrane Can you point me to the ATtiny core that you used? The examples in examples/rf24_ATTiny/* folder aren't compiling in the Arduino IDE using this Board Manager contribution.

@TMRh20 @Avamander I'm undo-ing these changes on my fork's "formatting-examples" branch.

[TMRh20]

I wouldn’t worry about it too much as many ATTimy users will be able to figure things out for themselves. Just as long as you don’t forget about fixing it. :p

…

On Oct 26, 2020, at 8:39 PM, Brendan ***@***.***> wrote:  I may have prematurely merged this. @jscrane Can you point me to the ATtiny core that you used? The examples in examples/rf24_ATTiny/* folder aren't compiling in the Arduino IDE using this Board Manager contribution. @TMRh20 @Avamander I'm undo-ing these changes on my fork's "formatting-examples" branch. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub, or unsubscribe.

[2bndy5]

Its weird because PlatformIO had no problem, but I'm trying to add a specific/individual CI job for compiling against attiny85/84 using the Arduino CLI action that @per1234 lead me to... and that's where I noticed things are broken. Undo-ing the changes allowed the IDE to successfully compile rf24ping85 by @tong67.

@tong67 The Arduino IDE doesn't like the timingSearch3pin.ino example due to the use of Serial.print(). Rightfully so, I don't think the ATtiny85 has the ability to print to the USB's Serial connection (especially since programming the ATtiny85 through Arduino IDE uses another MCU as an ISP -- sorry about all the initials, I can elaborate if needed). The compiler output says note: suggested alternative: 'Stream' for every line that Serial.print() is used.

[per1234]

Can you point me to the ATtiny core that you used?

From the issue title, I'm sure it's this one:
https://github.com/SpenceKonde/ATTinyCore

That is the most popular core for the ATtiny parts. The damellis/attiny project you linked to is the original, but not much used anymore. damellis/attiny just references the Arduino AVR Boards core library, which works to some extent, but very little effort was made in that core to provide support for the ATtiny parts, whereas SpenceKonde has gone to great lengths to provide amazing support for the ATtiny parts in ATTinyCore's custom core library.

[2bndy5]

yeah, I should've checked that before posting. I have since switched to using that core. Side note: I think the digispark is better supported with that core as it now includes the optional use of the micronucleus bootloader (very exciting -- need to do some more testing).

[2bndy5]

I take that back... these changes work with the SpenceKonde ATTiny core. We should specify this in the rf24_ATTiny folder's examples' docs.

reverted back to using these changes.

@tong67 the timingSearch3pin example doesn't compile, but I got the errors down to just problems about redefining SPI::transfer(), SPI::begin(), and SPI::end(). Full error output:

C:\Users\%USERNAME%\AppData\Local\Temp\arduino_build_442045\libraries\SPI\SPI.cpp.o (symbol from plugin): In function `USI_impl::clockoutUSI2(unsigned char, unsigned char)':
(.text+0x0): multiple definition of `SPIClass::transfer(unsigned char)'
C:\Users\%USERNAME%\AppData\Local\Temp\arduino_build_442045\sketch\timingSearch3pin.ino.cpp.o (symbol from plugin):(.text+0x0): first defined here
C:\Users\%USERNAME%\AppData\Local\Temp\arduino_build_442045\libraries\SPI\SPI.cpp.o (symbol from plugin): In function `USI_impl::clockoutUSI2(unsigned char, unsigned char)':
(.text+0x0): multiple definition of `SPIClass::begin()'
C:\Users\%USERNAME%\AppData\Local\Temp\arduino_build_442045\sketch\timingSearch3pin.ino.cpp.o (symbol from plugin):(.text+0x0): first defined here
C:\Users\%USERNAME%\AppData\Local\Temp\arduino_build_442045\libraries\SPI\SPI.cpp.o (symbol from plugin): In function `USI_impl::clockoutUSI2(unsigned char, unsigned char)':
(.text+0x0): multiple definition of `SPIClass::end()'
C:\Users\%USERNAME%\AppData\Local\Temp\arduino_build_442045\sketch\timingSearch3pin.ino.cpp.o (symbol from plugin):(.text+0x0): first defined here
collect2.exe: error: ld returned 1 exit status
Using library RF24 at version 1.3.9 in folder: C:\Users\%USERNAME%\Documents\Arduino\libraries\RF24 
Using library SPI at version 1.0 in folder: C:\Users\%USERNAME%\Documents\ArduinoData\packages\ATTinyCore\hardware\avr\1.4.1\libraries\SPI 

NOTICE that thisline
Using library RF24 at version 1.3.9 in folder: C:\Users\%USERNAME%\Documents\Arduino\libraries\RF24
is actually referring to the unreleased changes from this PR.