nRF52833 DK UART Bootloader

RE: nRF52833 DK UART Bootloader

jon-bob — Fri, 13 Jan 2023 20:47:36 GMT

You're right Amanda; I didn't realize that hardware flow-control also had to be enabled/disabled within the sdk_config.h file. Everything is working as expected on my end now. Thank you for the help.

RE: nRF52833 DK UART Bootloader

Amanda Hsieh — Thu, 12 Jan 2023 15:21:20 GMT

Hi,

We are not sure what could be wrong here, but it's more likely that it may have something to do with HWFC. As far as I remember UART DFU uses HWFC. And you only use 2 pins with the USB-TTL cable. This may explain why when you open the virtual comport it works for you. Note that even though HWFC is defined as false in the board config, it's still defined as NRF_DFU_SERIAL_UART_USES_HWFC 1 in the sdk_config.h in the DFU. You could try to disable it in the sdk_config.h.

As far as I remember UART DFU only works at very slow speed if you don't use HWFC.

-Amanda H.

RE: nRF52833 DK UART Bootloader

jon-bob — Mon, 09 Jan 2023 15:20:32 GMT

Hmm, I thought this would work as the reference you linked states:

"The UART pins connected to the interface MCU are tri-stated when no terminal is connected to the virtual COM port on the computer."

Anyway, I update the bootloader UART pins to ones I believe are only mapped to headers (P1.01 & P1.02). Here's my updated `pca10100.h` file:

#define RX_PIN_NUMBER NRF_GPIO_PIN_MAP(1,1)
#define TX_PIN_NUMBER NRF_GPIO_PIN_MAP(1,2)
#define CTS_PIN_NUMBER 7
#define RTS_PIN_NUMBER 5
#define HWFC false

The behavior is similar to what was occurring previously. In this case a bootloader update attempted on the VCP (COM19 in my case) now fails, as I've moved the bootloader UART pins. But, it's still the case that a bootloader update on the USB-to-TTL (COM11) is only successful once the VCP communication is attempted. Here's my console output showing this:

devzone.nordicsemi.com/.../nrfutil-terminal-output2.txt

It seems like there's something "additional" being performed by the VCP update process, that's allowing for valid UART communication, which isn't being performed by my direction UART communication (i.e., my USB-to-TTL interface).

RE: nRF52833 DK UART Bootloader

Amanda Hsieh — Mon, 09 Jan 2023 14:06:48 GMT

Hi,

[quote user=""]I'm now attempting to connect a USB-to-TTL serial cable to pin headers (P0.06, P0.08, GND), but I'm not able to get this working.[/quote]

Try to use other pins because P0.06 and P0.08 are for the UART connections on nRF52833 and interface MCU. See Virtual COM port.

Regards,
Amanda H.