Nrf52840 UART connection problems [closed]

teliu gravatar image

asked 2017-12-07 13:02:18 +0100

Dear support team, I’m using nrf52840 with PCA10056 and SDK 14.1. I have problems of UART connection.

  1. I do believe that MCU has physical connections to nrf52840 GPIO pins of P0.05, P0.06, P0.07 and P0.08, which are used to UART connection between nrf52840 and MCU. Am I right?

  2. So if I want to set up UART connection between MCU and nrf52840, I must use these pins P0.05~P0.08 for my UART instance, right?

  3. If I starting with “examples\ble_peripheral\ble_app_uart”, and I want to hook up PDK with PC by UART connection, but I do not want to use the PDK MCU USB interface, so I just modify the UART pins from P0.05~P0.08 to P0.26(RXD), P0.27(TXD), P0.02(CTS), P1.15(RTS), and then use an FTDI USB to TTL232R(3.3V) convertor to connect to these pins(RX-TX, TX-RX, CTS-RTS, RTS-CTS) with my PC. Then I can see UART output on my PC with TeraTerm(or Putty)? And If I need two UART connection, I just need to create two UAR instances and enable them both in sdk_config.h. Am I Right?

  4. I found two kinds of UART related example in SDK14.1, include “examples\ble_peripheral\ble_app_uart” and “examples\peripheral\serial”. I found something different for the two examples. It seems like that ble_app_uart example uses FIFOs as buffers for UART data transferring. I’m not sure which one will be better for my application as a start point? Real-time performance? Low energy?

Could someone help me about this? Thank you in advance!

Best regards, Tengfei.

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Closed as "the question is answered, right answer was accepted" by Martin Børs-Lind at 2017-12-08 09:18:12 +0100

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MartinBL gravatar image

answered 2017-12-07 13:16:37 +0100

It sounds like you have got it all right.

  1. Yes. You can download the HW files here to see how it all connects: nRF52840 Preview DK Downloads
  2. Yes
  3. Yes
  4. If you want to make a BLE application I would suggest that you start with the ble_app_uart example. If you are just playing around with peripherals without BLE, I suppose the peripheral\uart example would be best. The peripheral UART example in SDK 14.2.0 also uses FIFO.
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Great! Martin, thanks a lot for your quick response!

tengfei ( 2017-12-08 06:25:55 +0100 )editconvert to answer

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Asked: 2017-12-07 13:02:18 +0100

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Last updated: des. 07