In an attempt to execute #5 , I've begun on this skeleton of a SPI-implementing macro. I've only written a few lines of Rust, and never a macro, so this is based on reading the relevant documentation and following the examples of the other macros in the directory (namely serial.rs). I haven't even tried to compile it yet. It's a Work in Progress, and not yet ready to merge.

Please give any and all feedback. I will continue to work on fleshing out the details.

Note that I've intentionally substituted the original "master"/"slave" terminology for the alternate "primary"/"secondary" terminology. Hence "piso" and "posi" instead of "miso" and "mosi" respectively.

~~do not merge this yet~~

~~This addition does not work yet and crashes the compiler.~~

Both examples work now. The port definitions are not at all complete though.]

Also I don't have any idea yet on how to add stuff like a display that can occupy exactly one set of pins (because it is hardwired there) and is easy to create.

I am using this example: https://github.com/Rahix/avr-hal/tree/d17a441a667dd65e5a9be75b0e71d1beadf93e84/boards/arduino-uno

I have also executed rustup component add rust-src

And it fails to compile with this error:

» cargo +nightly build --example uno-blink
   Compiling compiler_builtins v0.1.39
   Compiling nb v1.0.0
   Compiling cfg-if v0.1.10
   Compiling bare-metal v0.2.5
   Compiling void v1.0.2
   Compiling vcell v0.1.3
   Compiling ufmt-write v0.1.0 (https://github.com/Rahix/ufmt.git?rev=12225dc1678e42fecb0e8635bf80f501e24817d9#12225dc1)
   Compiling panic-halt v0.2.0
   Compiling nb v0.1.3
   Compiling avr-device v0.2.3
   Compiling ufmt v0.1.0 (https://github.com/Rahix/ufmt.git?rev=12225dc1678e42fecb0e8635bf80f501e24817d9#12225dc1)
   Compiling embedded-hal v0.2.4
LLVM ERROR: Not supported instr: <MCInst 258 <MCOperand Reg:1> <MCOperand Imm:15> <MCOperand Reg:40>>
error: could not compile `compiler_builtins`

To learn more, run the command again with --verbose.
warning: build failed, waiting for other jobs to finish...
error: build failed

My versions:

• rust

» rustup --version
rustup 1.23.1 (2020-12-03)
info: This is the version for the rustup toolchain manager, not the rustc compiler.
info: The currently active `rustc` version is `rustc 1.51.0-nightly (c8915eebe 2021-01-07)`

• avr

» avr-gcc --version
avr-gcc (Homebrew AVR GCC 9.3.0) 9.3.0
Copyright (C) 2019 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

• And macos 10.14

I'm trying to use the SPI library but it's not working as expected. The send method works fine and returns without incident, but the read method blocks forever.

    let byte = block!(spi.send(5u8).and_then(|_| spi.read()));
    if let Ok(byte) = byte {
        ufmt::uwriteln!(&mut serial, "wrote read {}\r", byte).unwrap();
    } else {
        ufmt::uwriteln!(&mut serial, "not wrote read\r").unwrap();
    }

It never makes it past the block macro, it seems that it's returning WouldBlock forever. All read does is try to flush, code here:

https://github.com/Rahix/avr-hal/blob/master/avr-hal-generic/src/spi.rs#L125

The is_write_in_progress is obviously true as expected, since a send was just executed. But it seems that the write complete status register is not being set.

https://github.com/Rahix/avr-hal/blob/master/avr-hal-generic/src/spi.rs#L127

Documentation for the SPI interrupt flag is in section 18.5.2 of this document:

http://ww1.microchip.com/downloads/en/DeviceDoc/Atmel-7810-Automotive-Microcontrollers-ATmega328P_Datasheet.pdf

I'm trying to debug this but any suggestions are welcome.

This is a post on how to connect serial devices to WSL: https://www.scivision.dev/usb-tty-windows-subsystem-for-linux/

On Linux, the Arduino doesn't show up as /dev/ttyACM0 but as for example /dev/ttyS3 when it's connected to Port 3.

This would perhaps conclude that changing this: SERIAL_PORT="/dev/ttyACM0" in uno-runner.sh to SERIAL_PORT="/dev/ttyS3" would do the trick but that's not the case I think because I get Inappropriate ioctl for device instead.

How can I make this work?

The Arduino supports PWM on a few ports, yet looking through ports.rs, the HAL only seems to allow digital outputs. Is there an example of doing analog writes? Does this require including a lower level implementation?

Following PR #88, some (uncommon!) baudrates seem to be unstable: Namely 14400, 28800, and 76800 seem to be problematic. Further analysis of the generated waveform is needed to determine what is the problem.

Relevant comment from the PR.

Cc: @explicite

Hello @Rahix

I just started making the sparkfun-pro-micro crate by copying and renaming everything from the arduino-leonardo one (26698a0a191).

@cecton, for the pins, just reference the schematic for your board. It shows quite well which MCU pin is named what on the PCB.

It honestly took me some time to see it on the schematics :sweat_smile: I used the right most diagram.

It doesn't really show D11 to D13 but I supposed this is assumed because of the order? So I did the same with A4-A5 (Please double check that b66921e87)

Closes #52

BACKGROUND

I'm attempting to follow various examples for writing timer driven interrupt service routines in rust targeting the AVR...similar to these examples in arduino c:

https://www.instructables.com/id/Arduino-Timer-Interrupts/ https://circuitdigest.com/microcontroller-projects/arduino-timer-tutorial

EXAMPLE c CODE

In these examples, there is a stanza for setting the various registers to set this up. Here's an extract:

//set timer1 interrupt at 1Hz
  TCCR1A = 0;// set entire TCCR1A register to 0
  TCCR1B = 0;// same for TCCR1B
  TCNT1  = 0;//initialize counter value to 0
  // set compare match register for 1hz increments
  OCR1A = 15624;// = (16*10^6) / (1*1024) - 1 (must be <65536)
  // turn on CTC mode
  TCCR1B |= (1 << WGM12);
  // Set CS10 and CS12 bits for 1024 prescaler
  TCCR1B |= (1 << CS12) | (1 << CS10);  
  // enable timer compare interrupt
  TIMSK1 |= (1 << OCIE1A);

Then these c examples show how to wire up an ISR:

ISR(TIMER1_COMPA_vect){...}

AVR-HAL rust CODE

In the avr-hal repo's various examples, I only see reference to the timer registers of tccr1b and tcnt1. Is this an oversight or is this because of some limitation on the platform? It would be really useful to see an example that included the other registers such as compare ocr1a and especially an example showing the use of an interrupt service routine like the common c ISR above.

Links: Here's the example code I am following, though I've looked at all the avr-hal examples that include a timer:

1. Create the timer
2. Configure prescaling (TCCR1B)
3. Reset/clear the timer (TCNT1)
4. Is this TCNT1 read the equivalent of an output compare register (OCR)?

REQUEST

An example that sets up 2 different timers, say timer0 and timer1, and instantiates an ISR. I assume this would mean properly setting the ocr0a and ocr1a registers...h

I am happy to assist with documentation and more examples, but I need some direction/guidance here.

I'm getting gibberish on serial port. I've uploaded examples to my Arduino Uno rev2 board via cargo +nightly run --example uno-serial and cargo +nightly run --example uno-adc. I've played with several baud_rates (switched uno-serial.rs example from 57600 to 9600). I cannot get the correct setup to retrieve the data. The upload process is correct and other examples (uno-blink.rs) are working correctly.

Also, code from Arduino IDE behaves correctly in terms of Serial port communication.

Heya,

just checked this out on Windows 10 with rust 1.47.0-nightly and tried to run the uno-blink example but got:

$ cargo build --example uno-blink
   Compiling arduino-uno v0.1.0 (C:\Users\grego\code\avr-hal\boards\arduino-uno)
error: unknown use of instruction mnemonic without a size suffix
  |
note: instantiated into assembly here
 --> <inline asm>:1:2
  |
1 |     in %al,0x35
  |     ^

error: invalid instruction mnemonic 'sei'
  |
note: instantiated into assembly here
 --> <inline asm>:1:2
  |
1 |     sei
  |     ^^^

error: aborting due to 2 previous errors

error: could not compile `arduino-uno`.

Same problem in WSL 2 Ubuntu with the same rust version. Any pointers would be appreciated, maybe it's something I could look at myself.

Hello!

I'm pretty new to cross-compiling.

I created a nix environment in which i can compile the .ELF file for some targets.

For example, the target avr-atmega328p.json works:

bash-5.1$ cargo build --target avr-specs/avr-atmega328p.json 
   Compiling compiler_builtins v0.1.85
   Compiling core v0.0.0 (/nix/store/r9ns07w4z808rpysvg4z84bx3q525yv7-rust-mixed/lib/rustlib/src/rust/library/core)
   Compiling avr-hal-generic v0.1.0 (https://github.com/rahix/avr-hal?rev=4170a773d4d76cc93433d2455ed8b14e573ebe70#4170a7
   [..... i am skipping some lines ....]
   Compiling helloworld v0.1.0 (/home/arne/Projects/hobby/rust-arduino-led-blink)
    Finished dev [optimized + debuginfo] target(s) in 20.01s

And i get target/avr-atmega328p/debug/helloworld.elf.

But the arduino that i have at my disposal is the atmega2560, i get the following output:

bash-5.1$ cargo build --target avr-specs/avr-atmega2560.json --verbose
       Fresh core v0.0.0 (/nix/store/r9ns07w4z808rpysvg4z84bx3q525yv7-rust-mixed/lib/rustlib/src/rust/library/core)
       Fresh rustc-std-workspace-core v1.99.0 (/nix/store/r9ns07w4z808rpysvg4z84bx3q525yv7-rust-mixed/lib/rustlib/src/rust/library/rustc-std-workspace-core)
       Fresh unicode-ident v1.0.6
       Fresh compiler_builtins v0.1.85
       Fresh proc-macro2 v1.0.49
       Fresh quote v1.0.23
       Fresh nb v1.0.0
       Fresh syn v1.0.107
       Fresh proc-macro-hack v0.5.20+deprecated
       Fresh rustversion v1.0.11
       Fresh ufmt-macros v0.2.0
       Fresh avr-device-macros v0.4.0
       Fresh nb v0.1.3
       Fresh ufmt-write v0.1.0
       Fresh bare-metal v1.0.0
       Fresh cfg-if v0.1.10
       Fresh void v1.0.2
       Fresh vcell v0.1.3
       Fresh ufmt v0.1.2
       Fresh paste v1.0.11
       Fresh embedded-hal v0.2.7
       Fresh avr-device v0.4.0
       Fresh cfg-if v1.0.0
       Fresh avr-hal-generic v0.1.0 (https://github.com/rahix/avr-hal?rev=4170a773d4d76cc93433d2455ed8b14e573ebe70#4170a773)
       Fresh panic-halt v0.2.0
       Fresh atmega-hal v0.1.0 (https://github.com/rahix/avr-hal?rev=4170a773d4d76cc93433d2455ed8b14e573ebe70#4170a773)
       Fresh arduino-hal v0.1.0 (https://github.com/rahix/avr-hal?rev=4170a773d4d76cc93433d2455ed8b14e573ebe70#4170a773)
   Compiling helloworld v0.1.0 (/home/arne/Projects/hobby/rust-arduino-led-blink)
     Running `rustc --crate-name helloworld --edition=2021 src/main.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --diagnostic-width=149 --crate-type bin --emit=dep-info,link -C opt-level=s -C panic=abort -C lto -C debuginfo=2 -C debug-assertions=on -C metadata=fbe7e5f7c81a8527 -C extra-filename=-fbe7e5f7c81a8527 --out-dir /home/arne/Projects/hobby/rust-arduino-led-blink/target/avr-atmega2560/debug/deps --target /home/arne/Projects/hobby/rust-arduino-led-blink/avr-specs/avr-atmega2560.json -C incremental=/home/arne/Projects/hobby/rust-arduino-led-blink/target/avr-atmega2560/debug/incremental -L dependency=/home/arne/Projects/hobby/rust-arduino-led-blink/target/avr-atmega2560/debug/deps -L dependency=/home/arne/Projects/hobby/rust-arduino-led-blink/target/debug/deps --extern arduino_hal=/home/arne/Projects/hobby/rust-arduino-led-blink/target/avr-atmega2560/debug/deps/libarduino_hal-b20db3fb6d901e6a.rlib --extern 'noprelude:compiler_builtins=/home/arne/Projects/hobby/rust-arduino-led-blink/target/avr-atmega2560/debug/deps/libcompiler_builtins-03a22ee3553a16ba.rlib' --extern 'noprelude:core=/home/arne/Projects/hobby/rust-arduino-led-blink/target/avr-atmega2560/debug/deps/libcore-8e43a845006832d0.rlib' --extern embedded_hal=/home/arne/Projects/hobby/rust-arduino-led-blink/target/avr-atmega2560/debug/deps/libembedded_hal-2eda8d6ea831d148.rlib --extern nb=/home/arne/Projects/hobby/rust-arduino-led-blink/target/avr-atmega2560/debug/deps/libnb-1af58d0fb3475ee9.rlib --extern panic_halt=/home/arne/Projects/hobby/rust-arduino-led-blink/target/avr-atmega2560/debug/deps/libpanic_halt-d2460f22359f919f.rlib --extern ufmt=/home/arne/Projects/hobby/rust-arduino-led-blink/target/avr-atmega2560/debug/deps/libufmt-a9534496297e0ed1.rlib -Z unstable-options`
error: linking with `avr-gcc` failed: exit status: 1
  |
  = note: LC_ALL="C" PATH="/nix/store/r9ns07w4z808rpysvg4z84bx3q525yv7-rust-mixed/lib/rustlib/x86_64-unknown-linux-gnu/bin:/nix/store/g2nfbpind37b3v3y6zbszmcgfmrj5v7x-patchelf-0.15.0/bin:/nix/store/wn31i3dzwahz6ccws8bs1nwyqrpgsvj7-gcc-wrapper-11.3.0/bin:/nix/store/sxdx80lmk4zkhb51f4x5dgqvxgmx55wl-gcc-11.3.0/bin:/nix/store/s7ip867mrpnnjlppbnxlcsq10gv13x2x-glibc-2.35-224-bin/bin:/nix/store/h8gvq6r4hgpa71h44dmg9qfx03mj81sv-coreutils-9.1/bin:/nix/store/62fb427ncxaaksa2k59rhbilfg68v20x-binutils-wrapper-2.39/bin:/nix/store/frh9l9nrdysasdi2gs7i241s241ngjw2-binutils-2.39/bin:/nix/store/bzc9c4x9fqwjaxs0g45qkahabc0gv75f-avrdude-7.0/bin:/nix/store/fznym4mxp2q5r0bg6zdpska27xcq1iv3-ravedude-0.1.5/bin:/nix/store/r9ns07w4z808rpysvg4z84bx3q525yv7-rust-mixed/bin:/nix/store/88awvrn16car4z5xx516drhpbl2sp5h8-avr-stage-final-gcc-wrapper-11.3.0/bin:/nix/store/7zlcl5m0vq5cl5kcl1swb67wczms78al-avr-stage-final-gcc-11.3.0/bin:/nix/store/5kh0ddszrd1d04z61kw1b2302z7mbnkp-avr-libc-avr-2.1.0/bin:/nix/store/qyrv5scy0pda6cm10mdn66nd6shh907a-avr-binutils-wrapper-2.39/bin:/nix/store/kzjyiw72pi5d7hgyrs0l1fgqq31zj6cs-avr-binutils-2.39/bin:/nix/store/h8gvq6r4hgpa71h44dmg9qfx03mj81sv-coreutils-9.1/bin:/nix/store/zml88vnkpm8if114qkbbqd1q7n3ypqqy-findutils-4.9.0/bin:/nix/store/49y3r0gr9m6k20d91kl6dgp4b9a6m72v-diffutils-3.8/bin:/nix/store/5dv5cq1lwvsijr9p16p2kp79g1dbajk3-gnused-4.8/bin:/nix/store/bcvccw6y9bfil6xrl5j7psza7hnd16ry-gnugrep-3.7/bin:/nix/store/l1fp0hyca54xbb85vfhppd16bskzx8dg-gawk-5.1.1/bin:/nix/store/89zbjdkb48ma61k76l2mzn3s0ra0wn2c-gnutar-1.34/bin:/nix/store/qs8qb1swpivkfq7i9yd52n0mw6z4ij81-gzip-1.12/bin:/nix/store/wwkyfg8b34xy16zzc9p6rkh59p4q37qx-bzip2-1.0.8-bin/bin:/nix/store/i0x4pzj96qwvkrm94317l6jbi53a2rdj-gnumake-4.4/bin:/nix/store/4xw8n979xpivdc46a9ndcvyhwgif00hz-bash-5.1-p16/bin:/nix/store/793iwfbjvg7wgpqq7r83a1qjl1yg02sf-patch-2.7.6/bin:/nix/store/a3mwv26f99ycsv9w6hrx0jjjjywvcb1n-xz-5.2.9-bin/bin:/nix/store/camlh5laf1wsklghk0vcaw7gvx4rpzd1-file-5.43/bin:/home/arne/.nix-profile/bin:/nix/var/nix/profiles/default/bin:/home/arne/.cargo/bin:/home/arne/.nix-profile/bin:/nix/var/nix/profiles/default/bin:/usr/local/bin:/usr/bin:/usr/local/sbin:/usr/lib/jvm/default/bin:/usr/bin/site_perl:/usr/bin/vendor_perl:/usr/bin/core_perl:/home/arne/.cabal/bin:/home/arne/.ghcup/bin:/home/arne/.yarn/bin:/home/arne/.emacs.d/bin:/home/arne/.yarn/bin:/home/arne/.emacs.d/bin" VSLANG="1033" "avr-gcc" "-mmcu=atmega2560" "-Wl,--as-needed" "/tmp/nix-shell.pCNOuF/rustcaIPZ4U/symbols.o" "/home/arne/Projects/hobby/rust-arduino-led-blink/target/avr-atmega2560/debug/deps/helloworld-fbe7e5f7c81a8527.arduino_hal-b20db3fb6d901e6a.arduino_hal.4ff7873c-cgu.0.rcgu.o.rcgu.o" "-Wl,--as-needed" "-L" "/home/arne/Projects/hobby/rust-arduino-led-blink/target/avr-atmega2560/debug/deps" "-L" "/home/arne/Projects/hobby/rust-arduino-led-blink/target/debug/deps" "-L" "/nix/store/r9ns07w4z808rpysvg4z84bx3q525yv7-rust-mixed/lib/rustlib/avr-atmega2560/lib" "-Wl,-Bstatic" "/home/arne/Projects/hobby/rust-arduino-led-blink/target/avr-atmega2560/debug/deps/libcompiler_builtins-03a22ee3553a16ba.rlib" "-Wl,-Bdynamic" "-lgcc" "-Wl,-znoexecstack" "-L" "/nix/store/r9ns07w4z808rpysvg4z84bx3q525yv7-rust-mixed/lib/rustlib/avr-atmega2560/lib" "-o" "/home/arne/Projects/hobby/rust-arduino-led-blink/target/avr-atmega2560/debug/deps/helloworld-fbe7e5f7c81a8527.elf" "-Wl,--gc-sections" "-no-pie"
  = note: /nix/store/kzjyiw72pi5d7hgyrs0l1fgqq31zj6cs-avr-binutils-2.39/bin/avr-ld: skipping incompatible /nix/store/5kh0ddszrd1d04z61kw1b2302z7mbnkp-avr-libc-avr-2.1.0/avr/lib/avr5/libm.a when searching for -lm
          /nix/store/kzjyiw72pi5d7hgyrs0l1fgqq31zj6cs-avr-binutils-2.39/bin/avr-ld: skipping incompatible /nix/store/5kh0ddszrd1d04z61kw1b2302z7mbnkp-avr-libc-avr-2.1.0/avr/lib/avr3/libm.a when searching for -lm
          /nix/store/kzjyiw72pi5d7hgyrs0l1fgqq31zj6cs-avr-binutils-2.39/bin/avr-ld: skipping incompatible /nix/store/5kh0ddszrd1d04z61kw1b2302z7mbnkp-avr-libc-avr-2.1.0/avr/lib/avr4/libm.a when searching for -lm
          /nix/store/kzjyiw72pi5d7hgyrs0l1fgqq31zj6cs-avr-binutils-2.39/bin/avr-ld: skipping incompatible /nix/store/5kh0ddszrd1d04z61kw1b2302z7mbnkp-avr-libc-avr-2.1.0/avr/lib/avr5/libc.a when searching for -lc
          /nix/store/kzjyiw72pi5d7hgyrs0l1fgqq31zj6cs-avr-binutils-2.39/bin/avr-ld: skipping incompatible /nix/store/5kh0ddszrd1d04z61kw1b2302z7mbnkp-avr-libc-avr-2.1.0/avr/lib/avr3/libc.a when searching for -lc
          /nix/store/kzjyiw72pi5d7hgyrs0l1fgqq31zj6cs-avr-binutils-2.39/bin/avr-ld: skipping incompatible /nix/store/5kh0ddszrd1d04z61kw1b2302z7mbnkp-avr-libc-avr-2.1.0/avr/lib/avr4/libc.a when searching for -lc
          /nix/store/kzjyiw72pi5d7hgyrs0l1fgqq31zj6cs-avr-binutils-2.39/bin/avr-ld: avr architecture of input file `/tmp/nix-shell.pCNOuF/rustcaIPZ4U/symbols.o' is incompatible with avr:6 output
          collect2: error: ld returned 1 exit status
          

error: could not compile `helloworld` due to previous error

Caused by:
  process didn't exit successfully: `rustc --crate-name helloworld --edition=2021 src/main.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --diagnostic-width=149 --crate-type bin --emit=dep-info,link -C opt-level=s -C panic=abort -C lto -C debuginfo=2 -C debug-assertions=on -C metadata=fbe7e5f7c81a8527 -C extra-filename=-fbe7e5f7c81a8527 --out-dir /home/arne/Projects/hobby/rust-arduino-led-blink/target/avr-atmega2560/debug/deps --target /home/arne/Projects/hobby/rust-arduino-led-blink/avr-specs/avr-atmega2560.json -C incremental=/home/arne/Projects/hobby/rust-arduino-led-blink/target/avr-atmega2560/debug/incremental -L dependency=/home/arne/Projects/hobby/rust-arduino-led-blink/target/avr-atmega2560/debug/deps -L dependency=/home/arne/Projects/hobby/rust-arduino-led-blink/target/debug/deps --extern arduino_hal=/home/arne/Projects/hobby/rust-arduino-led-blink/target/avr-atmega2560/debug/deps/libarduino_hal-b20db3fb6d901e6a.rlib --extern 'noprelude:compiler_builtins=/home/arne/Projects/hobby/rust-arduino-led-blink/target/avr-atmega2560/debug/deps/libcompiler_builtins-03a22ee3553a16ba.rlib' --extern 'noprelude:core=/home/arne/Projects/hobby/rust-arduino-led-blink/target/avr-atmega2560/debug/deps/libcore-8e43a845006832d0.rlib' --extern embedded_hal=/home/arne/Projects/hobby/rust-arduino-led-blink/target/avr-atmega2560/debug/deps/libembedded_hal-2eda8d6ea831d148.rlib --extern nb=/home/arne/Projects/hobby/rust-arduino-led-blink/target/avr-atmega2560/debug/deps/libnb-1af58d0fb3475ee9.rlib --extern panic_halt=/home/arne/Projects/hobby/rust-arduino-led-blink/target/avr-atmega2560/debug/deps/libpanic_halt-d2460f22359f919f.rlib --extern ufmt=/home/arne/Projects/hobby/rust-arduino-led-blink/target/avr-atmega2560/debug/deps/libufmt-a9534496297e0ed1.rlib -Z unstable-options` (exit status: 1)

I don't understand why it doesn't work for the latter target.

The repository is here: https://github.com/arnemileswinter/rust-arduino-cross-compile-nix-blinking-led and is based on the cargo template.

Thanks in advance!

    Hmm, I also found this [Stackoverflow Answer](https://electronics.stackexchange.com/a/390541) which might give a good base:

"4" The last digit marks the series of chips. Within a series they are often pin-compatible and share a similar set of features. Some prominent series are:

• 'no digit' - these are the first generation chips with 8 to 128 kiB Flash
• '8' - a series from 4 to 32 kiB Flash, all in the same housing. More or less an improved version of the original chips
• '4' similar to '8', but in larger packages with more pins (~40 instead of ~30) and up to 128 kiB Flash
• '5' similar to '4', but with more timers and PWM channels
• '0','1' rather old family with large packages (60 - 100 pins) and up to 256 kiB Flash.
• '9' with integrated LCD controller
• 'U2', 'U4' are the two sizes of USB-enabled controllers
• '08', '09' newest family with additional configurable logic and more CPU-bypassing features
• '50', '90' the largest chips with 100 pins, but few peripherals

I think we can group some of them even more. For a start, I'd (without looking deeper) group the ATmega devices like this:

• no digit
• 8, 4, 5
• 0, 1
• U*

for the others, we don't currently have any devices supported, so we can take care of them later. For the ATtiny devices, I think we can try to merge the info from your link with this kind of 'generation' numbering scheme, to derive a sensible partitioning.

What also needs to be evaluated is how to name those crates ... Not sure what would be intuitive.

Originally posted by @Rahix in https://github.com/Rahix/avr-hal/issues/94#issuecomment-736545626

Adds support for ATmega8 (https://github.com/Rahix/avr-device/pull/112 has to be resolved first for this to work correctly).

ATmega8 is more challenging, because it does not work like the atmegas that were already implemented in some ways

1. EEPROM does not have modes (erase, erase and write), completely different mechanism is required.

2. WDT registers have different names "s" is missing from wdtcsr.

3. Does not have DIDR for ADCs

4. USART does not have "0" at end. It's just USART, not USART0. It has registers UBRRL, UBRRH instead of just one UBRR. I don't think it's possible to merge into just one register using patches as the UBRRH is shared with UCSRC and it's not directly next to UBRRL.

5. WDT does not have the same prescalers. It also does not support 4k ms and 8k ms. The rest of the prescalers does not exactly match the values.

6. I implemented a new macro that is named impl_eeprom_atmega_old. I am not sure if this name fits.

7. I added paste macro and passed in a string name of the register

8. I created a no_didr macro that does not contain anything in the relevant method. I don't think there is anything else to be done in that method, but I may be wrong here. I have not used ADCs that much.

9. as ATmega8 looks very specific regarding USART, I decided to not even create a macro, but instead implement it directly in atmega-hal/wdt.rs. There is a few differences to usart macro, namely UCSRC and UBRRH are functions, UCSRC has to have set URSEL to one (that says UCSRC should be set instead of UBRRH as they share the same location in memory). UBRR is set by UBRRH and UBRRL instead of just UBRR.

10. I have used the closest values and put panic!() to 4k ms and 8k ms. I think there should be a better solution than this...

What do you think about these changes? Do you have better idea how to implement ATmega8?

I have tested EEPROM, USART, ADCs (and using ports of course) so far. I will try to test the rest in short time.

When running cargo build I get the following error:

   Compiling proc-macro2 v1.0.47
error[E0635]: unknown feature `proc_macro_span_shrink`
  --> .cargo/registry/src/github.com-1ecc6299db9ec823/proc-macro2-1.0.47/src/lib.rs:92:30
   |
92 |     feature(proc_macro_span, proc_macro_span_shrink)
   |                              ^^^^^^^^^^^^^^^^^^^^^^

error: aborting due to previous error

For more information about this error, try `rustc --explain E0635`.
error: could not compile `proc-macro2`

To learn more, run the command again with --verbose.

Currently, ATMega644 is supported in avr-devices but not in avr-hal and, if a meaningful difference exists, neither supports ATMega644A. It would be nice to see these supported.

Hello,

I followed your guide on generating a new project with avr-hal-template and chose 'Arduino Uno' in the template menu.

When I execute cargo run, I get:

Finished dev [optimized + debuginfo] target(s) in 7.65s
     Running `ravedude uno -cb 57600 -P /dev/ttyACM0 target/avr-atmega328p/debug/sensor.elf`
       Board Arduino Uno
 Programming target/avr-atmega328p/debug/environment-sensor.elf => /dev/ttyACM0
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x00
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 2 of 10: not in sync: resp=0x00

The Arduino IDE gives exactly the same error.

However, after some investigation with arduino-cli, I found out I need the megaAVR core rather than the (I think) non-mega avr core that is used by ravedude:

$ ./arduino-cli board list
Port         Protocol Type              Board Name            FQBN                    Core
/dev/ttyACM0 serial   Serial Port (USB) Arduino Uno WiFi Rev2 arduino:megaavr:uno2018 arduino:megaavr

Using the listed FQBN with arduino-cli on the 'blink' example sketch, the sketch gets successfully uploaded and starts running on the target:

$ ./arduino-cli compile --fqbn arduino:megaavr:uno2018 blink
$ ./arduino-cli upload -p /dev/ttyACM0 --fqbn arduino:megaavr:uno2018 blink
avrdude: usbdev_open(): WARNING: failed to set configuration 1: Device or resource busy

It seems the warning can be ignored in this case, although I can't say what other process is actually using the device while doing this.

My questions for you:

• Is this a known issue and do you have pointers to solutions?
• If not, can I configure ravedude to use the above FQBN?
• If not, can you point me where I need to extend the ravedude code to support this? I don't seem to be able to locate the core setting in the generated config for avrdude.