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Bare-metal blinky project

How To Use

Prerequisites

Make sure all required software is installed correctly and available in your PATH.

Build the firmware:

Clone the project, go to the bare-metal project folder and build it:

git clone https://github.com/blinky101/blinky_lpc11uxx.git
cd blinky_lpc11uxx/bare-metal
make all

Flash the firware to your board

This step flashes the firmware via the Black Magic Probe. Flashing via OpenOCD is also possible, but not covered in this documentation.

arm-none-eabi-gdb -nx --batch \
-ex 'target extended-remote /dev/ttyACM0' \
-ex 'monitor swdp_scan' \
-ex 'attach 1' \
-ex 'load' \
-ex 'set mem inaccessible-by-default off' \
-ex 'set {int}0x40048000 = 2' \
-ex 'compare-sections' \
-ex 'kill' \
blinky.elf

The output will look similar to this:

Loading section .text, size 0x184 lma 0x0
Start address 0xd4, load size 388
Transfer rate: 3 KB/sec, 388 bytes/write.
Section .text, range 0x0 -- 0x184: matched.
Kill the program being debugged? (y or n) [answered Y; input not from terminal]

Debugging via gdb

This works similarly to flashing. Connect your debugger to the target board, and run the following command:

arm-none-eabi-gdb \
-ex 'target extended-remote /dev/ttyACM0' \
-ex 'monitor swdp_scan' \
-ex 'attach 1' \
-ex 'set mem inaccessible-by-default off' \
-ex 'set {int}0x40048000 = 2' \
blinky.elf

This should drop you into a gdb console.

FAQ

Why does the Black Magic Probe not work? How do I find the correct /dev/tty* file?

Try plugging the black Magic Probe in and out and observing the differences in /dev/. On linux, /dev/ttyACM0 or similar is expected, on MacOS it will look like /dev/cu.<serial_number>.

I want to power the target board via the Black Magic Probe

The official Black Magic Probe has this capability, but it is disabled by default. If your board is 3.3V compatible, run this command to enable the power:

arm-none-eabi-gdb -nx --batch -ex 'target extended-remote /dev/ttyACM0' -ex 'monitor tpwr enable'

How does the code work?

The bare-metal project is optimized for having minimal dependencies, which does make the code a bit confusing to read. Also, a lot of corners were cut to keep the dependencies minimal: basing a real project on this code is not recommended. Please have a look at the basic and cpm projects.