Merge pull request #68 from oleo65/python-flash-script

Introduces Python helper script for flashing with OpenOCD (pyocd)

flashing/pyocd/.gitignore

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+__pycache__/

flashing/pyocd/README.md

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+# Flashing with pyocd
+
+This is a different approach to flash the firmware on the b-parasites. It is completely optional.
+
+## Basic instructions
+
+(Based on the discussion in issue #67)
+
+The instructions will probably differ slightly depending on your debugging probe and hardware setup.
+
+The setup is fairly straightforward and documented in the `pyocd` [docs](https://pyocd.io/).
+
+I used an inexpensive debugging probe from Aliexpress called `nanoDAP` from `Muse Labs` which is less than 10 € and readily available. The J-LINKs are hard to get and quite expensive. In my understanding basically all `CMSIS-DAP`-compatible probes which are recognized by `pyocd` should work.
+
+After connecting the debugging probe via usb and connecting the b-parasite as described in the wiki, flashing was easy and fast.
+
+For a complete flashing of softdevice and firmware use the provided python script. Assuming you put the `*.hex` files in default locations it boils down to one simple command:
+
+```
+python ./flash_firmware.py
+```
+
+For help and documentation of the available command line flags use
+
+```
+python ./flash_firmware.py -h
+```

flashing/pyocd/flash_firmware.py

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+import argparse
+
+from pathlib import Path
+
+from pyocd.core.helpers import ConnectHelper
+from pyocd.core.target import Target
+from pyocd.flash.file_programmer import FileProgrammer
+
+from mac_address_reader import MacAddressReader
+
+parser = argparse.ArgumentParser()
+parser.add_argument("-s", "--softdevice", action="store", help="Optional file path to softdevice file.", default="../../sdk/s140nrf52720/s140_nrf52_7.2.0_softdevice.hex", type=Path)
+parser.add_argument("-f", "--firmware", action="store", help="Optional file path to firmware file.", default="../../code/b-parasite/_build/nrf52840_xxaa.hex", type=Path)
+parser.add_argument("--skip-softdevice", action="store_true", help="Skip flashing of the softdevice.")
+parser.add_argument("--skip-firmware", action="store_true", help="Skip flashing of firmware.")
+
+args = parser.parse_args()
+
+with ConnectHelper.session_with_chosen_probe() as session:
+
+    board = session.board
+    target: Target = board.target
+
+    if not args.skip_softdevice:
+        softdevice_path: Path = args.softdevice
+        print(f"Flashing softdevice {softdevice_path.name}...")
+        FileProgrammer(session).program(str(softdevice_path))
+
+        target.reset_and_halt()
+        target.resume()
+
+    if not args.skip_firmware:
+        firmware_path: Path = args.firmware
+        print(f"Flashing firmware {firmware_path.name}...")
+        FileProgrammer(session).program(str(firmware_path))
+
+        target.reset_and_halt()
+        target.resume()
+    
+    mac_address_reader = MacAddressReader(target)
+    mac_address = mac_address_reader.get_static_mac_address()
+    print(f'Static manufacturer MAC address (DEVICEADDR): {mac_address}')

flashing/pyocd/mac_address_reader.py

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+from pyocd.core.target import Target
+
+
+class MacAddressReader():
+
+    MEMORY_ADDRESS = 0x100000A4
+    
+    def __init__(self, target: Target) -> None:
+        self.target = target
+
+    def get_static_mac_address(self) -> str:
+        '''
+        Reads the static mac address assigned by the manufacturer. 
+        
+        This chip property is readonly and may be different from the mac address in the application code.
+        '''
+        memory_blocks = self._get_blocks()
+
+        return self._convert_blocks(memory_blocks)
+
+    def _get_blocks(self):
+        memory_blocks = self.target.read_memory_block32(self.MEMORY_ADDRESS, 2)
+
+        return memory_blocks
+
+    def _convert_blocks(self, memory_blocks: list[int]) -> str:
+        first_block = f'{memory_blocks[0]:x}'.rjust(8, '0')
+
+        modified_second_block = memory_blocks[1] | 0xc000 # Bitwise OR
+
+        second_block = f'{modified_second_block:x}'
+
+        mac_string = (second_block[4:] + first_block)
+        prettified_mac = ':'.join(mac_string[i:i+2] for i in range(0, len(mac_string), 2))
+
+        return prettified_mac.upper()

flashing/pyocd/requirements.txt

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+pyocd>=0.34.1