STM32L0x1 Mass erase with pyOCD

Stm32L0x1Eraser.py

from pyocd.core.exceptions import TransferError
from pyocd.core.helpers import ConnectHelper
from pyocd.core.target import Target
from usb.core import USBError
import time

class Stm32L0x1Eraser():
    FLASH_PECR = 0x40022004
    FLASH_PDKEYR = 0x40022008
    FLASH_PKEYR = 0x4002200C
    FLASH_PRGKEYR = 0x40022010
    FLASH_OPTKEYR = 0x40022014
    FLASH_SR = 0x40022018
    FLASH_OPTR = 0x4002201C
    FLASH_WRPROT1 = 0x40022020
    FLASH_WRPROT2 = 0x40022080
    FLASH_OPT_BASE = 0x1ff80000

    def wait_flash_busy(self, target: Target):
        result = 1,
        while result != 0:
            result = target.read32(self.FLASH_SR) & 0b1

    def mass_erase(self):
        """
        This toggles the Read Protection Level from 0 to 1 and then 0, so that it can achieve a mass erase.
        Check out RM0377's FLASH sections and A.3.12 Mass Erase code example
        """
        with ConnectHelper.session_with_chosen_probe(options={
            "target_override": "stm32l071kbux",
            "logging": {
                "loggers": {
                    "pyocd.board.board": {
                        "level": "CRITICAL"  # Shut up the board logging
                    }
                }
            }
        }) as session:
            board = session.board
            target = board.target

            target.reset_and_halt()

            # Unlock flash
            target.write32(self.FLASH_PKEYR, 0x89abcdef)
            target.write32(self.FLASH_PKEYR, 0x02030405)
            self.wait_flash_busy(target)

            target.write32(self.FLASH_PRGKEYR, 0x8c9daebf)
            target.write32(self.FLASH_PRGKEYR, 0x13141516)
            self.wait_flash_busy(target)

            target.write32(self.FLASH_OPTKEYR, 0xfbead9c8)
            target.write32(self.FLASH_OPTKEYR, 0x24252627)
            self.wait_flash_busy(target)

            # Detect RDPROT
            optr_ret = target.read32(self.FLASH_OPTR)
            if optr_ret & 0xff == 0xCC:  # Level 2
                raise ValueError('You are on RDP Level 2, got a second-hand chip??')
            elif optr_ret & 0xff == 0xAA:  # Level 0 - default
                print("Setting RDP level to 0 to 1 first...")

                # Enable erasing
                target.write32(self.FLASH_PECR, 0x200)
                self.wait_flash_busy(target)

                # Erase the OPT1
                target.write32(self.FLASH_OPT_BASE, 0)
                self.wait_flash_busy(target)

                # Try OBR_LAUNCH to commit option bytes change
                # This will reboot the MCU
                try:
                    target.write32(self.FLASH_PECR, 0x40000)
                    session.close()
                    time.sleep(1)
                    self.mass_erase()
                except (TransferError, USBError):
                    print('No ACK anymore - MCU probably restarts')

            else:  # Level 1 - Set to Level 0
                print("Setting RDP level to 1 to 0 to trigger mass erase...")
                opt_lsb = optr_ret & 0xffff
                opt_lsb &= (~0xff)
                opt_lsb |= 0xAA
                opt_write = (~opt_lsb) << 16 | opt_lsb
                target.write32(self.FLASH_OPT_BASE, opt_write)
                self.wait_flash_busy(target)

                # Try OBR_LAUNCH to commit option bytes change
                # This will reboot the MCU
                try:
                    target.write32(self.FLASH_PECR, 0x40000)
                    session.close()
                    print('Done~!')
                except (TransferError, USBError):
                    print('No ACK anymore - MCU probably restarts')