Hi!
I'm trying to pass the BLE data to the PC using nrf52840 DK.
To do so, I've started with the ble_app_uart example and it was able to build fundamental features–find BLE device, get BLE notification, and send to PC via FIFO.
But the problem is that 1) a lot of data are missing during the UART procedure and 2) throughput seems to be lower than what I expected.
It was able to get a clean result with a low BLE data transmission rate (32k bps) and a low UART baud rate (115200).
The BLE data rate should be at least 10 times higher (320k bps, and 640k bps for the ideal). It means that I need to increase the UART baud rate to more than 460800.
But when I increase the baud rate to more than 230400, the data become weird.
For example, when I check the BLE packet with the nRF Connect application, a repeated 30-C8 (00110000-11001000) appears. But the UART result is 91-E8 (10010001-11101000).
This is quite a huge problem for me because all the bytes are in the form of 00xxxxxx-11xxxxxx.
Fortunately, in the case of the 460800 baud rate, this happens very few times but for the 921600 baud rate, the error becomes the major.
I may build my applications with the 460800 baud rate, but I want to be sure why this happens and whether I can solve the problem. Is there any related information?
Also, I'm curious whether the hardware flow control is working...
I turned on the flow control option by changing NRFX_UARTE_DEFAULT_CONFIG_HWFC, NRFX_UART_DEFAULT_CONFIG_HWFC, UART_DEFAULT_CONFIG_HWFC to 1 but it seems there is no difference with those options are turned off.
P.S. I found the usbd_ble_uart example, but what is the advantage of using CDC ACM USB? Is there any performance improvement than JLink CDC UART port?
