# Rust Embedded Workshop Notepad

This document is for alignment during the workshop. Don't be too shy to extend the document and help others. 🦀:blush:

Workshop page: https://braun-embedded.com/workshop/
Workshop package: https://braun-embedded.com/barcelona-2019-11-09.zip

## Thanks
Thank you for the great workshop Hanno and Matthias!

## Open questions :construction: :tada:

This is your place to add new questions and raise issues. We'll try to answer them collaboratively.

## Known issues

### Installing OpenOCD on NixOS
Use the package from https://pastebin.com/wEYHhM7z . If you need it, you can use the binary cache at https://thequux.cachix.org/ to save some compile time.

### Installing OpenOCD on macOS

You need a pretty recent version of OpenOCD. Homebrew is your friend.

brew install open-ocd --HEAD

### Error: arm-none-eabi-gdb

error: could not execute process `arm-none-eabi-gdb -tui -q -x openocd.gdb target/thumbv6m-none-eabi/release/examples/gpio_simple` (never executed)

Caused by:
  No such file or directory (os error 2)

Please install the [GNU toolchain for your platform](https://developer.arm.com/tools-and-software/open-source-software/developer-tools/gnu-toolchain/gnu-rm/downloads). For macOS, you can use [this homebrew tap](https://github.com/osx-cross/homebrew-arm).
> [name=Evan Schwartz] Does anyone know which package to use on Ubuntu?
> [name=Wouter Geraedts] `gdb-multiarch`, also change the path to `gdb-multiarch` in `.cargo/config`.

> [name=Wouter Geraedts]
> It's in the project-folder, i.e. `/minimal/.cargo/config`
> ```
> [target.thumbv6m-none-eabi]
> runner = "gdb-multiarch -tui -q -x openocd.gdb"
> ```

### Error: Clearing lockup after double fault

If you get the following error message when you run your code:

lpc84x.cpu -- clearing lockup after double fault

Program received signal SIGINT, Interrupt.
0xfffffffe in ?? ()
(gdb) cont
Continuing.
target not halted
target lpc84x.cpu was not halted when resume was requested

Please push the "reset" button on the LPCXpresso. That's the black button next to the white button. :wink:
After that, type `cont` or `continue` and hit `Enter`. The program should now run.

> [name=nrxus] Does this have to be done every time the program is restarted?

> [name=Wouter Geraedts] Mine stays in this mode and does not seem to run my code.

### Device not found

After `lpc8xx-hal$ cargo run --features=845-rt --example gpio_delay`

   ┌──examples/gpio_delay.rs─────────────────────────────────────────────────────────────────────────────────────┐
   │8       #[entry]                                                                                             │
   │9       fn main() -> ! {                                                                                     │
   │10          // Get access to the device's peripherals. Since only one instance of this                       │
   │11          // struct can exist, the call to `take` returns an `Option<Peripherals>`.                        │
   │12          // If we tried to call the method a second time, it would return `None`, but                     │
   │13          // we're only calling it the one time here, so we can safely `unwrap` the                        │
   │14          // `Option` without causing a panic.                                                             │
   │15          let p = Peripherals::take().unwrap();                                                            │
   │16                                                                                                           │
   │17          // Initialize the APIs of the peripherals we need.                                               │
   │18          let swm = p.SWM.split();                                                                         │
   │19          let mut delay = Delay::new(p.SYST);                                                              │
   │20          #[cfg(feature = "82x")]                                                                          │
   │21          let gpio = p.GPIO; // GPIO is initialized by default on LPC82x.                                  │
   │22          #[cfg(feature = "845")]                                                                          │
   └─────────────────────────────────────────────────────────────────────────────────────────────────────────────┘
exec No process In:                                                                                  L??   PC: ?? 
Info : only one transport option; autoselect 'swd'
Warn : Transport "swd" was already selected
target/openocd.cfg:8: Error: Can't find target/lpc84x.cfg
in procedure 'script' 
at file "embedded:startup.tcl", line 60
at file "target/openocd.cfg", line 8
openocd.gdb:1: Error in sourced command file:
Remote communication error.  Target disconnected.: Connection reset by peer.
(gdb) 

Now what?

> [name=Wouter Geraedts] ~~You probably are running Ubuntu. The scripts provided with the Ubuntu openocd do not have the specific `lpc84x.cfg` file.
> Change the file to `lpc8xx.cfg` in `openocd.cfg`. I.e.~~
> ```
> source [find target/lpc8xx.cfg]
> ```
>
> Ubuntu repository OpenOCD is outdated, compile OpenOCD yourself from [this mirror](https://github.com/ntfreak/openocd).
> Compile openocd with `./configure --enable-cmsis-dap`.

### Can't find target/openocd.cfg

> [name=gakonst] (MacOS).
> There is an openocd.cfg generated under `./target/thumbv6m-none-eabi/release/build/lpc8xx-hal-e9e3756869db2498/out/openocd.cfg`, copying it to `./target/openocd.cfg` doesn't help.

> [name=polly]
> Happens on arch for me
> [This](https://elinux.org/OpenOCD_Troubleshooting:_Can%27t_Find_File.cfg#Can.27t_Find_openocd.cfg) might be relevant

When running `cargo run --features=845-rt --example gpio_delay`

Reading symbols from target/thumbv6m-none-eabi/debug/examples/gpio_delay...
Open On-Chip Debugger 0.10.0+dev-00954-gded679902 (2019-11-05-14:28)
Licensed under GNU GPL v2
For bug reports, read
        http://openocd.org/doc/doxygen/bugs.html
embedded:startup.tcl:26: Error: Can't find target/openocd.cfg
in procedure 'script' 
at file "embedded:startup.tcl", line 26
openocd.gdb:1: Error in sourced command file:
Remote communication error.  Target disconnected.: Connection reset by peer.
(gdb) 

**SOLUTION: Revert to git hash `969b67d39a45895783b8e0662a272e8d3ce27d42`, at the moment of writing this HEAD does not work (due to last minute changes before the talk)** ;)

I'm running Debian 9 and the OCD version from apt was 0.9. I uninstalled it and downloaded it for that website. Then I have version 0.10. See question below about where to extract the tgz file?

> [name=gakonst] `brew install openocd` gave 0.10.0, still failing

### Compilation failure (Solved)
When running `cargo run --features=845-rt --example gpio_delay`

> rustc 1.32.0 (9fda7c223 2019-01-16)

error[E0658]: renaming imports with `_` is unstable (see issue #48216)
   --> src/lib.rs:145:13
    |
145 |     pub use crate::sleep::Sleep as _;
    |             ^^^^^^^^^^^^^^^^^^^^^^^^

error: aborting due to previous error

For more information about this error, try `rustc --explain E0658`.
error: Could not compile `lpc8xx-hal`.

**SOLUTION**: Update rust to latest stable version: rustc 1.39.0 (4560ea788 2019-11-04)
> rustup update

### warning: unrecognized item "timeout" in "qSupported" response

Full error:

warning: unrecognized item "timeout" in "qSupported" response
openocd.gdb:1: Error in sourced command file:
Remote communication error.  Target disconnected.: Connection reset by peer.

**Solution**: You're probably using stable openocd. Download the latest git version.
latest git version -- thequux
> [name=Evan Schwartz] I have this version and I'm still seeing the error: `xPack OpenOCD, 64-bit Open On-Chip Debugger 0.10.0+dev (2019-07-17-11:25)`

> [name=gakonst] I have `v0.10.0-esp32-20191008` from [here](https://github.com/espressif/openocd-esp32/releases), same problem.

> [name=flomonster] I might have a solution. After using the latest git version of openocd. Clean your project `cargo clean` then try to run it. (Let me know if it works for you)
> [name=Evan Schwartz] I tried that and still got `openocd.gdb:1: Error in sourced command file:` (this might be the [Unknown Error](#unknown-error) below)
> You need somehow to make OpenOCD view these files: https://github.com/espressif/openocd-esp32/tree/master/tcl/target.
> [name=nrxus] The `cargo clean` command worked for me

> [name=jap] `cargo clean` did not work for me, but unplugging the device did...
> [name=Evan Schwartz] Neither `cargo clean` nor unplugging the device worked for me :crying_cat_face:
> [name=gakonst] this is literally just the system being unable to find the config files, the error in sourced command file is the openocd.cfg file trying to import the file under interfaces/ :/ :sadface:
### Unknown error

> [name=Doc] This means your board is not detected
> In my case it was a bad USB cable !!!!!! <Insert angry face here>

openocd.gdb:1: Error in sourced command file:
Remote communication error.  Target disconnected.: Connection reset by peer.

> [name=pizzamig] You can re-run `cargo run` or type manually the commands contained in the openocd.gdb file:

target remote | openocd -f target/openocd.cfg
load
continue

Running `target remote` asks me to specify which device I'm connecting to, and even then, `openocd` run with the cfg file does not have the proper interface available

Error: The specified debug interface was not found (cmsis-dap)
The following debug interfaces are available:
1: ftdi
2: usb_blaster
3: ft232r
4: jlink
5: vsllink
6: ulink
7: hla
8: osbdm
9: opendous
10: aice
11: xds110

>[name=pizzamig] openocd has to be compiled with cmsis-dap enabled. An additional dependency is required, libhidapi, and `--enable-cmsis-dap` during configure

target/lpc8xx.cfg:10: Error: Can't find target/lpc1xxx.cfg
in procedure 'script' 
at file "embedded:startup.tcl", line 26
at file "./openocd_82x.cfg", line 6

>[name=pizzamig]Are you using `--features=845-rt`? `openocd_82x.cfg` is the configuration for a different board

### OCD setup

I downloaded OCD from https://github.com/xpack-dev-tools/openocd-xpack/releases/ an untared it to some dir `xPacks/openocd/0.10.0-13/`.

How is this supposed to be used because just having it unpacked will do nothing with it and the self check command `cargo run --features=845-rt --example gpio_delay` will no know about it. How are the executable and the config files found?

> [name=Evan Schwartz] I just manually added that folder to the path (`export PATH=/path/to/xPacks/openocd/0.10.0-13/:$PATH`)

> [name=pizzamig] openocd is invoked by gdb via the command `target remote | openocd -f target/openocd.cfg` (the first line of openocd.gdb) but it has to be reachable by your shell. Alternatively, you can modify the openocd.gdb file using an absolute pathname for openocd

### udev: configured OK? (Debian)

How to check that it is set up correctly?

Command: ...

Expected response: ....

### LED not working
Level of gpio and LED is counter intuitive for non-embedded developers

Solution:
set_high() -> led off
set_low() -> led on

> [name=Wouter Geraedts] Try running it in release mode with `cargo run --release`. This was what worked for me.

### Did someone got to interact with Touch capacitor?
Trying to read using `.read().istouch().bit_is_set()` but I guess there is some setup to do?