Bit/Character limit on Central and Peripheral example

RE: Bit/Character limit on Central and Peripheral example

Simonr — Thu, 25 Jul 2019 07:01:29 GMT

Could you check what the APP_UART_COMMUNICATION_ERROR returns? I suspect this is an OVERRUN error, which means that a start bit is received while the previous data still lies in RXD. What's recommended for higher baud rates is to implement the HW flow control as Håvard suggested early on. Is there a reason you can't do that? You could also try implementing the workaround he links to as well.

Best regards,

Simon

RE: Bit/Character limit on Central and Peripheral example

Aashay — Wed, 24 Jul 2019 14:26:19 GMT

so both boards are connected simply as serial ports. and i am talking to each other through tera term. and yes. i have tried all baudrates from 9600-921600 and nothing above 19200 works consistently without giving an error. so actually, i have commented out the error handler under APP_UART_COMMUNICATION_ERROR so that it can try to send as much. but if this were to be on, all the baudrates above 19200 would simply error out every time i try to send more than 7 or so characters in a .txt

RE: Bit/Character limit on Central and Peripheral example

Simonr — Wed, 24 Jul 2019 06:35:07 GMT

Are you using a JLINK device (DK or similar) to communicate with the computer? In that case, the baud rate of 921 600 is not supported due to the Baudrate calculations not matching that value. In our nRF52 DK user guide, this is stated as well. Are you not able to get any of the baud rates above 19200 to work either?

Best regards,

Simon

RE: Bit/Character limit on Central and Peripheral example

Aashay — Tue, 23 Jul 2019 14:17:53 GMT

all the baud rates i stated above, i would set using the sdk_config.h. so what could be the problem

RE: Bit/Character limit on Central and Peripheral example

Simonr — Tue, 23 Jul 2019 05:57:29 GMT

What have you set the baud rate as in your sdk_config.h file? By default, this should be set to 115200 in our examples, but you can modify this in your projects sdk_config.h file.

Best regards,

Simon

RE: Bit/Character limit on Central and Peripheral example

Aashay — Mon, 22 Jul 2019 16:44:18 GMT

another update: so with the same code, i am running at different baudrates. at 921600 when i try to send a file .txt, only 6 characters pass through when the file could have 12+ characters. but when the baudrate is 9600 or even 19200, i can accurately send over 100+ characters without any error. the buffer sizes are 256 for tx and rx. so what could be causing the data to be incomplete at baud rates after 19200?

RE: Bit/Character limit on Central and Peripheral example

Aashay — Mon, 22 Jul 2019 14:11:15 GMT

Simonr the size is set to 256 on both, should i increase it or is that enough and something else is causing this?

RE: Bit/Character limit on Central and Peripheral example

Simonr — Mon, 22 Jul 2019 07:58:06 GMT

What's your UART_TX_BUF_SIZE and UART_RX_BUF_SIZE set as? You could try to increase these values to reserve more RAM for the buffer. You can change this to the number you require as long as you keep the RAM size in mind and the buffer size is a power of 2.

Best regards,

Simon

RE: Bit/Character limit on Central and Peripheral example

Aashay — Fri, 19 Jul 2019 20:14:58 GMT

update: so i figured out why i cant use flow control. the program i am using doesn't enable the cts and rts lines in the first place so me trying to enable them is why i was getting the error. is there any other way i could increase the how many characters or bits i can pass through the buffer at once?

RE: Bit/Character limit on Central and Peripheral example

Aashay — Fri, 19 Jul 2019 19:41:15 GMT

so in the program i am using. i have to connect a board and then send data through. so with the 'disabled' i would be able to connect the boards but when sending data, errors would cause failure. with 'enabled' on the same code, i am not able to even connect my board. i dont exactly know why that is.

RE: Bit/Character limit on Central and Peripheral example

Håvard — Fri, 19 Jul 2019 03:56:53 GMT

In main.c I found the line

.flow_control = APP_UART_FLOW_CONTROL_DISABLED,

and changed it to

.flow_control = APP_UART_FLOW_CONTROL_ENABLED,

RE: Bit/Character limit on Central and Peripheral example

Aashay — Thu, 18 Jul 2019 22:00:14 GMT

how did you enable flow control? thanks

RE: Bit/Character limit on Central and Peripheral example

Håvard — Thu, 18 Jul 2019 19:59:45 GMT

Hi,

I tested with SDK 15.3

ble_app_uart on one board, and ble_app_uart_c on the other. (I tested with nRF52840 and not nRF52832).

I noticed that the peripheral app, ble_app_uart, asserted when I loaded large text files (but worked fine with 18 characters and a bit more).

Digging down in the drivers I wonder if this ultimately comes from an overrun error (A start bit is received while the previous data still lies in RXD).

Enabling flow control fixed the issue for me, and let me send larger files.

Graceling explored a different workaround in this thread.

Good luck!