Two UART's pin configuration in nRF52833 QFN40

[Sai Mukesh]

Hi,

     I want to develop a device using nRF52833. I am using QFN40, so can I use two UART connections. If yes, then what are the Tx, Rx pins for both the UART's

[Jørgen Holmefjord]

Hi,

Yes, nRF52833 supports two UARTE instances (UARTE0 and UARTE1), as you can see in Registers. All nRF52 series chips has a pin crossbar feature, allowing any GPIO to be assigned to any serial peripheral like UART, SPI, TWI, etc. You should however avoid using pins marked as "Standard drive, low frequency I/O only" in Pin assignments for high frequency peripherals. The pins are controlled in FW, and both UARTE instances needs to be configured and initialized before use.

Best regards,
Jørgen

[Jørgen Holmefjord]

Hi,

Like I said in my previous reply, ALL GPIOs can be assigned to the UARTs, but not all are recommended. Here is a table of available GPIOs on nRF52833 QFN40 package and their recommended usage:

Green shows GPIOs with no restriction. Red shows pins with frequency/drive restrictions, which should be avoided. I have also marked some pins in yellow. The yellow pins are shared with other functionality (32.768 kHz crystal pins and pin reset), so you might also want to avoid these pins if these functionalities are used in your product

Best regards,
Jørgen

[Jørgen Holmefjord]

See my answer in this ticket. The programming procedure are the same for all nRF52 series chips.

[Sai Mukesh]

Hi,

What are the pins I have to use for programming.

[Jørgen Holmefjord]

[Sai Mukesh]

Hi,

We tried the same process but it is not working.

[Sai Mukesh]

We tried the same process but it is not working. Could you provide us any other process to flash the program ?

[Jørgen Holmefjord]

What have you tried and what is not working? The chip comes blank from the factory and there is no other ways to do the initial programming of the chip than through the SWD pins.

[Sai Mukesh]

Hi,

Can I use GPIO Standard drive, low frequency I/O for LED, Switch

[Jørgen Holmefjord]

Yes, as long as the switching frequency of the pin is below 10kHz and you do not draw large current from the pin (standard drive can source/sink a maximum of 1-4mA according to GPIO Electrical Specification).

[Sai Mukesh]

what are the pins need to consider while i need to flash program from nRF52840 DK to external nRF52833 QDAA QFN40 SOC and share the procedure 

[Jørgen Holmefjord]

Sai Mukesh said:

what are the pins need to consider while i need to flash program from nRF52840 DK to external nRF52833 QDAA QFN40 SOC and share the procedure 

Make the following connections:

• VDD from DK to VDD on your custom board
• GND from DK to GND on your custom board
• SWDIO from DK to SWDIO on your custom board
• SWDCLK from DK to SWDCLK on your custom board
• VTG on DK to VDD on DK or on your custom board

The VTG/SWDIO/SWDCLK pins are available on P20 header on nRF52840 DK.