Can not enter application after readback protect?

[Susan_cfx]

Hi ,

I wirte a python script to download FW to nRF52832 custom board, the FW is the merged file with softdevice（s132_nrf52_7.0.1_softdevice.hex）, bootload, bootload settings, and application,  then setting readback protect. 

After setting readback protect, our board just advertising DfuTarg，it seems enter bootload, didn't enter application.

the python script is as follows,

api = LowLevel.API("NRF52")
    sleep(1)
    try:
        api.open()
        api.connect_to_emu_with_snr(jlink_serial, swd_speed)

        # Program the parsed hex into the device's memory.
        test_program = Hex.Hex(hex_file_path)
        print("Writing %s to device..." % hex_file_path)

        for segment in test_program:
            api.write(segment.address, segment.data, True)

        api.sys_reset()
        api.go()
        api.readback_protect(2)   # or api.write_u32(0x10001208, 0x00,True)

        api.pin_reset()
        api.close()

If I comment out api.readback_protect(2)，our board can enter application and works ok .  
In addtion, I download the same FW with nRF connect Programmer, our board can enter application and works ok.
I download another FW, which is merge file with eddystone example，bootload,softdevice, and bootload settings,
it has the same problem，always enter the bootload, attached please find this FW.
1602.ed_sd_bl_set_app.hex

Please help analyze the reason, thank you very much.

[Susan_cfx]

Hi Vidar,

According to your suggestion, I checked the version of mergehex , it is  version: 10.4.1.

And I modified the programming script,  as shown in the example highlevel_programe_hex.py,  it gives the same result.

Before if I don't set readback_protect, the application can run. if set readback_protect, still advertsing DfuTarg.

Following is the script,

def program_target(dut):
    global jlink_serial, swd_speed, hex_file_path
    print ("Flash DUT with production firmware")

    api = HighLevel.API("NRF52")  #add by Susan

    sleep(1)

    dut.hexfilemd5=md5(hex_file_path)
    try:
        api.open()
      #  api.connect_to_emu_with_snr(jlink_serial, swd_speed)  # comment out by Susan
        probe = HighLevel.DebugProbe(api, jlink_serial)   #add by Susan

        dut.hexfilename = hex_file_path
        print("Writing %s to device..." % hex_file_path)

        # Make a program option struct to modify programming sequence.
        # If ommitted, the default programoptions struct specifies ERASE_ALL, SYSTEM_RESET, and VERIFY_NONE.
        #following add by Susan
        
        program_options = HighLevel.ProgramOptions(
            erase_action=HighLevel.EraseAction.ERASE_ALL,
            reset=HighLevel.ResetAction.RESET_SYSTEM,
            verify=HighLevel.VerifyAction.VERIFY_READ
        )
        
        probe.program(hex_file_path, program_options=program_options)

        sleep(1)  # if don't add sleep time, will advertising DfuTarg.
        probe.readback_protect()
     #   probe.reset()  # if add reset, will except APIError.
        probe.close()

        dut.flash_success = True
        dut.programtime = str(datetime.datetime.now())
        return dut

    except HighLevel.APIError:
        print ("Programming adapter not found!---1")
        dut.failure_desc="No programming adapter or programming failed!"

        probe.close()  #add by susan
        dut.flash_success = False
        return dut

 I try to  add sleep time delay 0.01 seconds before probe.readback_protect,  the application can run, why?

sleep(0.01)     # if don't add sleep time, will advertising DfuTarg.
probe.readback_protect()
# probe.reset()   # if add reset, will except APIError.
probe.close()

After probe.readback_protect(),  do I need to add probe.reset() ?  

Try previous programming script,  which use the LowLevel API,  just add sleep time before api.readback_protect(2), test 10 times, the applicaiton can run. 

def program_target(dut):
    global jlink_serial, swd_speed, hex_file_path
    print ("Flash DUT with production firmware")
    
    api = LowLevel.API("NRF52")  
    sleep(1)

    dut.hexfilemd5=md5(hex_file_path)
    try:
        api.open()
        api.connect_to_emu_with_snr(jlink_serial, swd_speed)  # comment out by Susan

        # Program the parsed hex into the device's memory.
        test_program = Hex.Hex(hex_file_path)
        dut.hexfilename = hex_file_path
        print("Writing %s to device..." % hex_file_path)

        for segment in test_program:
            api.write(segment.address, segment.data, True)
            content = api.read(segment.address, len(segment.data))
            if not segment.data == content:
                print ("Program data mismatch starting at address: {}, segment length: {}".format(str(segment.address, 'x'), str(len(segment.data))))
                raise LowLevel.APIError
                break

        print (str(datetime.datetime.now()) + ": Resetting target...")
        api.sys_reset()   
        api.go()
        
        sleep(0.01)  # if don't add sleep time, will advertising DfuTarg.
        
        api.readback_protect(2)   # or api.write_u32(0x10001208, 0x00,True)
        print ("Pinreset...")
        api.pin_reset()
        api.close().

        dut.flash_success = True
        dut.programtime = str(datetime.datetime.now())
        return dut
        
    except LowLevel.APIError:
        print ("Programming adapter not found!---1")
        dut.failure_desc="No programming adapter or programming failed!"
        api.close()   
        dut.flash_success = False
        return dut

What is differrent between HighLevel API and LowLevel API ?  Which one should I use first？

Is it necessary to increase sleep time before readback protection? 

Please help me to check above two programming script , any problem, please help to corret, thank you very much.

Best regards,

Susan