CommonSense

Firmware for the CommonSense project.

Compile and Run

The firmware depends on the S132 softdevice. Before running the firmware, the softdevice has to flashed to the chip.

Flashing the Softdevice

1. Erase the chip

   $ probe-rs erase --chip nRF52832_xxAA
   

2. Flash the softdevice

   $ probe-rs download --verify --binary-format hex --chip nRF52832_xxAA s132_nrf52_7.3.0_softdevice.hex
   

Compile and Run

1. Install the required tools. Consult Dockerfile for specifics
2. Build the firmware

   $ cargo build --release
   

3. Flash / run the firmware

   $ cargo fr
   $ # OR
   $ cargo run --release
   

Compile and Run using Docker

1. Build the docker image

   $ docker build . -t commonsense
   

2. Build the firmware

   $ docker run --rm -v $PWD:$PWD -w $PWD -u $(id -u):$(id -g) commonsense cargo build --release
   

3. Flash / run the firmware

   $ docker run --privileged -v /dev/bus/usb/:/dev/bus/usb --rm -v $PWD:$PWD -w $PWD -u $(id -u):$(id -g) commonsense cargo fr
   $ # OR
   $ docker run --privileged -v /dev/bus/usb/:/dev/bus/usb --rm -v $PWD:$PWD -w $PWD -u $(id -u):$(id -g) commonsense cargo run --release
   

Notes

• If flashing fails after being successful the first time, take a look at this: https://users.rust-lang.org/t/probe-rs-fails-to-work-after-first-time-use-successful/103234
• This may be useful for unit testing: https://crates.io/crates/embedded-test
• Currently this project is being developed on the nrf52-dk board with the nrf52832 chip. When mature enough, it will be ported to the nrf52810 to run on the actual hardware. Locations to modify:
  • memory.x - consult the nrf-softdevice documentation for more information
  • Cargo.toml - change the nrf52832 feature to nrf52810
  • .cargo/config.toml - change the nrf52832 chip to nrf52810
• TODO: Find out how to properly set up the license (the softdevice is proprietary)
• If the device locks up, use the nrf-recover utility
• Pinning to use nRF52DK as programmer
• For examples of how to use embassy to program nRF chips, see https://github.com/embassy-rs/embassy/tree/main/examples (and look for nrfXXX)

Troubleshooting

Core locking up

One possible cause for the core to lock up is to have a flash memory configuration that doesn't match the selected softdevice.

Background

When the device powers up, it looks for certain things at certain positions in memory, namely the interrupt vector table and the program entrypoint. The interrupt vector table and entrypoint it finds are from the softdevice. After initialization, the softdevice then attempts to hand over control to the user program. The user program again has an interrupt vector table and an entrypoint that are expected to be at a certain position in memory. Specifically, they are expected to be right after the softdevice. If they are not there, the device enters a hard fault state and locks up the core.

This means that the flash memory configuration in memory.x has to be correct for the program to start up properly:

MEMORY
{
  FLASH : ORIGIN = 0x00000000 + <softdevice size>, LENGTH = <flash memory size> - <softdevice size>
  ...
}

The softdevice size can be found in the release notes of the softdevice. This is a pdf that is downloaded along with the hex file from the nordic website. The flash memory size depends on the model of microcontroller used.

Solution

1. Make sure memory.x is configured correctly for the selected softdevice. E.g., for S112 running on an nRF52832 chip:

   MEMORY
   {
     FLASH : ORIGIN = 0x00000000 + 100K, LENGTH = 512K - 100K
     RAM : ORIGIN = 0x20000000 + 30K, LENGTH = 64K - 30K
   }
   

2. Recover the device from it's locked state. This erases the flash memory:

   $ probe-rs erase --chip nRF52832_xxAA --allow-erase-all
   

3. Compile and flash the program:

   $ cargo run --bin blinky --release
   

   The program will not run successfully at this time, as it requires the softdevice to be flashed as well.
4. Flash the desired softdevice, e.g., S112:

   $ probe-rs download --verify --binary-format hex --chip nRF52832_xxAA s112_nrf52_7.3.0_softdevice.hex