Synopsis

Exposes readings from an ADC pin (currently: PA3) of the board via a TCP service on the Ethernet port.

Network Protocol

Sensor readings produce lines of key=value pairs, joined by ,, terminated by "\r\n".

t=21000,pa3=685
t=22000,pa3=684
t=23000,pa3=681
t=24000,pa3=696
t=25000,pa3=673
t=26000,pa3=689
t=27000,pa3=657
t=28000,pa3=654
t=29000,pa3=652
t=30000,pa3=662
t=31000,pa3=663

Key	Value	Unit
t	Time	ms
pa3	ADC reading	mV

LEDs

Colors indicate what the MCU is occupied with.

Color	Indication
Green	WFI (idle)
Blue	Network poll
Red	Message broadcast

Crate features

• semihosting enables log output via the cortex-m-semihosting crate. Use only in development! MCU will hang when no OpenOCD is running.

• generate-hwaddr generates an Ethernet MAC address by hashing the unique device ID from flash memory.

Instructions

Build the firmware with default.nix

• nix-build
• This uses cargo-vendor to bundle dependencies, so that unstable versions from git can be used.
• Run result/bin/flash-adc2tcp to flash a devboard with OpenOCD and quit.

Development environment with shell.nix

• nix-shell
• Spawning openocd, the devboard should be connected already.
• Instructions (cargo run --release) are printed.