UART DFU for nRF52833

[rcerati]

HW setup is my boart connected to a windows10 PC with an uart link.

I tried secure_bootloader_pca10100_uart_ses_nRF5SDKThreadv4.1.0.zip example, with some modification for my board, es UART pins in custom_board.h

#define RX_PIN_NUMBER 7
#define TX_PIN_NUMBER 6
//#define TX_PIN_NUMBER 35
#define CTS_PIN_NUMBER 8
#define RTS_PIN_NUMBER 40
#define HWFC true

To validate uart pins changes I tested the uart example in examples\peripheral\uart\pca10100\blank\ses and it works fine both without HW flow control and with HW flow control.

When I send 

nrfutil dfu serial -pkg blinky_pca10100_mbr.zip -p COM5 -b 115200

it seems all freezed: RTS signal from PC goes low, but nRF52833 RTS pin remains high. If I force low that signal PC starts transmitting.

A second question

The DFU example uses (in sdk_config.h) Button for entering DFU mode and set NRF_BL_DFU_ENTER_METHOD_BUTTON_PIN to 25: in my board I cannot access to that pin and I want to use PIN0.2.

I set in custom_board.h

#define BUTTON_4       2

and in sdk_config.h

#define NRF_BL_DFU_ENTER_METHOD_PINRESET 1

I add Enter DFU mode on pin reset

Is it correct ?

How can I debug the DFU example ?

Best Regards

[rcerati]

Now  interface chip works !

With PCA10100 board connected to PC with a usb cable on j2 connector, I programmed fw with MSD functionality, then I tried to use virtual com with nrfutil but it didn't work.

All changes if I program the board with 

nrfjprog -f NRF52 --sectorerase --program NORDIK_SDK_v4\examples\dfu\secure_bootloader\pca10100_uart\ses\Output\Release\Exe\secure_bootloader_uart_mbr_pca10100.hex --reset

Now nrfutil is able to program the chip

nrfutil dfu serial -pkg blinky_pca10100_mbr.zip -p COM6 -b 115200

  [####################################]  100%

Device programmed.

I want to perform another test with the PCA10100 board:

move nRF52833 UART on other pins, using pins P1.01/02/03/04, and connect the UART to the PC with an external USB-UART serial bridge.

[rcerati]

With nrfjprog I've programmed a DFU that uses an UART on P1 pins, and then dowloaded a program

nrfutil dfu serial -pkg blinky_pca10100_mbr.zip -p COM5 -b 115200
[####################################] 100%
Device programmed.

Three questions:

1) PC UART waits 30 seconds before to lower RTS signal and start download, is it correct ?

2) I tried to download heart_rate_demo.hex, 

nrfutil dfu serial -pkg heart_rate_demo.zip -p COM5 -b 115200
[####################################] 100%
Device programmed.

but the program seems not work because LED1 and LED3 are lit on the DK (the DK has bootloader mode active). 

When I copy heart_rate_demo on the disk of interface MCU, the  heart_rate_demo works fine and the DK connects to the smartphone.

What's wrong ?

3) it is not clear for me the use of mbr: is it necessary include it with DFU bootloader ?

Best Regards

[Vidar Berg]

The bootloader will not be aware of the application if it was programmed directly through the debug interface and will thus as a result fall back to DFU mode. Please read the "Combine application, bootloader and softdevice image - Bootloader setting" section at the end of this post: https://devzone.nordicsemi.com/nordic/short-range-guides/b/software-development-kit/posts/getting-started-with-nordics-secure-dfu-bootloader.  It goes through the necessary steps to make the bootloader aware of the app after it has been programmed with the Jlink.

[rcerati]

Now I'm able to merge MBR, bootloader, application, bootloader settings in a single file for production, and it starts and enter in bootloader mode when I press Button 4 at power-on.

However if I set NRF_BL_DFU_ENTER_METHOD_PINRESET instead of  NRF_BL_DFU_ENTER_METHOD_BUTTON I'm not able to enter in bootloader mode (LED 1 and 3 on): the program never enters in bootloader mode with reset button also if I use nrfjprog and nrfutil or Jlink programmer and program the board in "old style" manner.

CONFIG_GPIO_AS_PINRESET is defined in bootloader project and also in application program project.

Which checks can I perform ?

Thanks

[Vidar Berg]

Is the board reset when you press the reset button?

[rcerati]

There is blinky firmware running: if I press reset button nothing happens, blinky continues to work.

By the way, if I copy heart_rate_demo on the disk of interface MCU, the  heart_rate_demo seems not to works because the DK doesn't connect to the smartphone. The demo worked some days ago (see previous message), I'm following the readme instructions.

[Vidar Berg]

Please try to erase the chip, then re-program the FW with either the Programmer app in nRF Connect for Desktop, or nrfjprog.

[rcerati]

For heart_rate_demo, the smartphone Bluetooth had a problem I suppose, because

I tried

nrfjprog -f NRF52 --chiperase --program ..\..\tools\heart_rate_demo\heart_rate_demo\heart_rate_demo.hex
Parsing hex file.
Erasing user available code and UICR flash areas.
Applying system reset.
Checking that the area to write is not protected.
Programming device.

and it is ok.

About the other question, reset seems to have no effect while application firmware is running: with reset button is not possible to enter in bootloader mode.

Best Regards

[Vidar Berg]

rcerati said:

About the other question, reset seems to have no effect while application firmware is running: with reset button is not possible to enter in bootloader mode.

 Sounds like the pinreset is not working then. Please double check that the reset button on your board is connected to P0.18 and also read out UICR.PSELRESET[n] to verify that the register is set. E.g., nrfjprog --memrd 0x10001200.

[rcerati]

nrfjprog --memrd 0x10001200
0x10001200: 00000015                              |....|

and

nrfjprog --memrd 0x10001204
0x10001204: 00000015                              |....|

It seems not setted the right pin

shuld I reprogram the register with

nrfjprog --memwr 0x10001200 --val 0x12 --verify

and

nrfjprog --memwr 0x10001204 --val 0x12 --verify

??

[Vidar Berg]

It appears to be mismatch between your project configuration and chip target. Make sure the project is built with 'system_nrf52833.c' and not system_nrf52.c

[rcerati]

The project was built with 'system_nrf52.c': I changed it with 'system_nrf52833.c' and now reset button works.

I also checked

nrfjprog --memrd 0x10001200
0x10001200: 00000012                              |....|

The project includes also ses_startup_nrf52.s;

should I change it with ses_startup_nrf52833.s ?

If I want to test NRF_BL_DFU_ENTER_METHOD_GPREGRET:

I'm adding

NRF_POWER->GPREGRET = (uint8_t val) 0x1;

in an application program.

Is it all needed to enter in DFU mode or it is needed to force a soft reset ?

Thank you

Best Regards