pyOCD user script for RP2040

rp2040.py

# pyOCD user script
# 'usb_boot' command will put target RP2040 into bootloader mode
# 
# Howto invoke:
# pyocd cmd --script rp2040.py -c usb_boot

options.update({
    "target_override": "rp2040",
})

if not "frequency" in options:
    options.set("frequency", 10000000)

@command(help="Kick-start USB Bootloader")
def usb_boot():
    target.halt()
    # Enable XOSC
    target.write32(0x40024000, target.read32(0x40024000) & ~0x00FFF000 | 0x00FAB000)
    ptr = target.read16(0x14)
    usb_boot_addr = 0
    while True:
        code = target.read16(ptr)
        addr = target.read16(ptr+2)
        ptr += 4
        if code == 0:
            break
        # print(f"code = 0x{code:04X}  addr = 0x{addr:04X}")
        if code == 0x4255: # 'UB'
            usb_boot_addr = addr & ~1
    if usb_boot_addr == 0:
        print("Error: could not find function address")
        return
    target.write_core_register('r0', 0)
    target.write_core_register('r1', 0)
    target.write_core_register('sp', 0x20041f00)
    # target.write_core_register('pc', 0x2590)
    target.write_core_register('pc', usb_boot_addr)
    target.resume()