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nRF52 UART connection with constant data stream capability

Hello, I am working on a project where I have 2 nRF52832 boards with the PCA10040. I have the example developer code examples. I am using the central and peripheral code examples to talk from one UART to another on Tera Term. Although, I noticed that this code is structured so that data is piled in an array and only sent to the other UART when I press "enter" or if it reaches a maximum size (which is very large). I am only using Tera Term to test my boards and not as part of the project. I have an external source of data that works properly on its own and am trying to use these UARTs to establish wireless communication. I have cut the solder bridges SB 22-25 to isolate PO.05 - PO.08 from nRF52832 to the Interface MCU. In pins 6 and 8 on both boards, I put TXD and RXD. Essentially what I am trying to do is have data go though the TXD & RXD wires to one UART, then wirelessly transfer data to the other UART, and have TXD & RXD wires come back. This processes will not work unless the code is structured so that data can be processed (sent & received) continuously. Or at least have it to where whatever is stacked up in the buffer is sent out every interval. I have attached the part of the code for both Central and Peripheral examples that specifically deal with data in UART. I have also put a diagram of sorts to help visualize. Any help would be great. Thanks.

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  • hey  thanks so much for these. So i tried them out on tera term to confirm that they work and they do work correctly. so i used this configuration for the actual data i am trying to pass through the two boards. The program i am using connects and recognizes the boards, but when i try to pass data through, it gives an error saying "nullable objects must have a value". I am pretty sure that this program passes data in hex and many times it sends NULL, which is 0x00 in hex. I predict that our code isnt sending this properly. it might be not sending NULL altogether, which might be why there is an error? any recommendations on what to do or where to start? If my explanation doesn't make sense, just let me know. i can try to explain it better.

  • Hi,

    It sounds like there may be a bug in the program you use, and based on the error, I guess you have access to the source code. I would suggest to debug the program and figure out where "nullable objects must have a value" gets returned.    

  • Hey, so i was thinking of a possible way to alter the timer. I wanted to make the timer so that it is dependent on the input rather than being a continuous timer loop. As of right now, I have the interval at about 50 ticks ( 50 ms ), and it seems fine but i feel changing this would fix some of the problems I am having. If i wanted to make it to where, everytime a character/bit of data is added to the array, the timer is reset. so as long as data keeps coming in, the timer keeps resetting. When the last bit of data were to come in, there would not be another for it to reset the timer. This is where the timer could turn on and send the data array at the end of the interval and stay on until the next bit is received and resets the timer. Is this possible at all. It seems simple in terms of logic but im sure it could be troublesome in the syntax.

  • Hi, you can try to call app_timer_stop() followed by app_timer_start() in the APP_UART_DATA_READY event. This should restart the timer every time you receive a byte on the UART interface. 

  • ok thanks so much. One more question. So using the app timer examples for both central and peripheral on teraterm, I used the send file option where I prerecorded characters on a .txt file. well both boards send the file as long as it is only 19 characters or less. if it goes above 19 characters, the uart restarts. how can i increase this size to something bigger?

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