NRF52832 Uart Tx Problem Hardware flow control

[bjornwilliam]

Using: SDK14 Softdevice132 V5.00 app_uart driver with legacy, no easy dma.

UART is set up with hardware flow control. The pins should be set up correctly: rx-tx , cts-rts and vice versa. P.0.08-P0.11 are used for UART

I am using the NRF52 connected via UART to our own MCU. Receiving data via UART on the NRF52832 works correctly as far as I can tell. However sending data via UART is not working at all.

nrf52debuguart.PNG Here is a screenshot of some uart communication. Our MCU sends $$$, and the NRF52 should answer with "CMD", however the NRF52 Tx is just low. When I debug the NRF52 it receives "$$$" and says that it sends "CMD". The weird thing is how NRF CTS and NRF TX has a spike at exactly the same place. There is no physical short between them.

Does anyone have any thoughts about some likely causes for this?

DROPBOX link to the complete project folder: www.dropbox.com/.../nrf52832-app.7z

Using the nrf52832-app\examples\ble_peripheral\ble_app_uart\pca10040\s132\arm5_no_packs Project file.

[Susheel Nuguru]

can you please share your project so that i can reproduce this issue? if you do not want to post it in public, then please open a case here. I will pick it from there and when we have an answer there, then please do care to come back here and update the answer.

[bjornwilliam]

Thank you! Added a dropbox link to the project.

[Susheel Nuguru]

Hi bjorn, i changed the pin numbers to

#define RX_PIN_NUMBER  8
#define TX_PIN_NUMBER  6
#define CTS_PIN_NUMBER 7
#define RTS_PIN_NUMBER 5
#define HWFC           true

And it worked correctly. If you are also using the DK then the pin numbers you are using are connected to NFC which could affect the behavior of the pins. If you still want to use the same pins as gpio then you have follow the instructions mentioned here

[bjornwilliam]

Thank you so much !