makepython-nrf: add bootloader instructions

YoeDistro · Jan 19, 2024 · 636ab50 · 636ab50
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diff --git a/boards/makepython-nrf52840/Makefile b/boards/makepython-nrf52840/Makefile
@@ -22,3 +22,9 @@ install: program
 .PHONY: program
 program: $(TOCK_ROOT_DIRECTORY)target/$(TARGET)/release/$(PLATFORM).bin
 	tockloader $(FLAGS) flash --address 0x10000 $<
+
+.PHONY: flash-bootloader
+flash-bootloader:
+	curl -L --output /tmp/makepython-nrf52840-bootloader_v1.1.3.bin https://github.com/tock/tock-bootloader/releases/download/v1.1.3/makepython-nrf52840-bootloader_v1.1.3.bin
+	tockloader flash --address 0 /tmp/makepython-nrf52840-bootloader_v1.1.3.bin
+	rm /tmp/makepython-nrf52840-bootloader_v1.1.3.bin
diff --git a/boards/makepython-nrf52840/README.md b/boards/makepython-nrf52840/README.md
@@ -11,3 +11,42 @@ display.
 ## Getting Started
 
 First, follow the [Tock Getting Started guide](../../doc/Getting_Started.md).
+
+The MakePython nRF52840 is designed to be programmed using an external JLink
+programmer. We would like to avoid this requirement, so we use the [Tock
+Bootloader](https://github.com/tock/tock-bootloader) which allows us to program
+the board over the UART connection. However, we still require the programmer one
+time to flash the bootloader.
+
+To flash the bootloader we must connect a JLink programmer. The easiest way is
+to use an nRF52840dk board.
+
+### Connect the nRF52840dk to the MakePython-nRF52840
+
+First we jumper the board as shown with the following pin mappings
+
+| nRF52840dk | MakePython-nRF52840 |
+|------------|---------------------|
+| GND        | GND                 |
+| SWD SEL    | +3V3                |
+| SWD CLK    | SWDCLK              |
+| SWD IO     | SWDDIO              |
+
+Make sure _both_ the nRF52840dk board and the MakePython-nRF52840 board are
+attached to your computer via two USB connections.
+
+Then:
+
+```
+make flash-bootloader
+```
+
+This will use JLinkExe to flash the bootloader using the nRF52840dk's onboard
+jtag hardware.
+
+### Using the Bootloader
+
+The bootloader activates when the reset button is pressed twice in quick
+succession. The green LED will stay on when the bootloader is active.
+
+Once the bootloader is installed tockloader will work as expected.