Short time dfu issues

[alien]

Hi guys！

Right now I have my custom board which used nRF52833 SoC. There is only one reset button on custom board and dfu performed via uart.

I flashed four hex file : application( one LED blink), softdevice(s140), settings, bootloader uart .

I chose NRF_BL_DFU_ENTER_METHOD_BUTTON_PIN and register way to enter dfu.

I changed NRF_BL_DFU_ENTER_METHOD_BUTTON_PIN number to  dtr/rts  gpio pin on custom board. 

also I use pyserial in python to control dtr and rts when serial is opened. And dtr/rts status is used to simulate button press.

the python script was just like this：

import time
import serial

ser = serial.Serial('COM5', 115200)

ser.setRTS(0)
#time.sleep(2)
ser.setRTS(1)
#time.sleep(2)
ser.setRTS(0)

time.sleep(2)
ser.close()

My problem is that:

1.When I opened serial and press reset button .the hardware can entered dfu mode but once the serial is closed,  the hardware will back to application immediately.

2.I also try to change register and do reset in application when the hardware detect dtr/rts pin voltage change . The result was the same.

So can anyone tell me what caused this and how can dfu mode stay?

This is my first time try to raise question in nordic devzone.

Thanks in advance!

[Hieu]

Hi alien,

I am unfamiliar with Python, but does the serial functionality that you are using controls DTR/RTS by default? I don't see HWFC parameters in the serial.Serial() line.

Hieu

[alien]

Hi Hieu,

I disabled HWFC in bootloder .

So DTR/RTS here is just used to simulate button press.

Like on PCA10056(nRF52840-dk), button 4 is used to enter dfu mode.

The voltage will be changed if you press it.

On my custom board. When serial is opened, DRT/RTS status can be easily changed through pyserial.

So no need to think about HWFC here. Thank you.

Alien

[Hieu]

Hi Alien,

Can you use the debug project of the bootloader, enable the debug level logging, and acquire the log?

Hieu

[alien]

Hi Hieu,

Since there is no example for pca10100 uart bootloader.

So I changed relevant settings in pca10040 uart example.

Only none-debug version can be successfully modified.

Is there any other way I can provide information for you?

I may also made mistakes in pca10040 uart debug bootloader example modification that lead to unsuccessful.

Alien

[Hieu]

Hi Alien,

You can run a comparison of the files between the pca10040 no-debug and with-debug project. Most of the differences are in sdk_config.h, and the memory region size in the project files.

By the way, what IDE are you using and at which version? Also, what version of the SDK are you using? Please remember to use the version listed in the release note of the SDK.

Hieu

[alien]

Hi Hieu,

Thanks for your reply!

Right now I may work it out by changing the nrfutil python script.

But I have met another problem:

I need to keep DTR always high when perform DFU.

Since I have disabled Flow Control.

The DTR will first stay high for a short time and stay low before the dfu is finished.

Can I keep DTR/RTS always high?

Alien

[Hieu]

Hi Alien,

You are talking about keeping DTR high on the nRF device, right? As you don't have HWFC on the nRF end, your UART peripheral are not actually controlling any pin as DTR. You should be able to just set a pin as a GPIO output and control it as you wish.

Could I be misunderstanding you somehow here?

Hieu

[alien]

Hi Hieu,

What if I have an individual usb to seiral pcb board. The chip is FT231X, it connected nRF device through GPIO. How can I keep dtr pin always high on the individual board.

Best

Alien

[Hieu]

Hi Alien,

If I understand the FT231X chip right, it is just a UART to USB bridge. If so, then as long as the nRF device DTR is raised high, it should also set DTR bit in the virtual COM port.

Best,

Hieu