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nrf52840 serial

If I put too many characters into a serial using IRQ mode, it stops reading input.

I haven't tried polling or DMA yet.

Using

  • nRF5_SDK_15.0.0_a53641a
  • gcc-arm-none-eabi 6.3.1 and I also tried segger
  • nRF52840-DK with a PCA10056 1.0.0
  • examples/peripheral/serial.

I can't get the onboard USB serial to work with flow control enabled(works with it disabled), so I'm doing testing with an FTDI breakout.

The serial example works consistently and correctly if I just type characters on the keyboard, but if I paste a chunk of text larger than 47 characters, the serial port reads between 20 and 40 characters, and then stops reading.

If I connect  a gps unit that emits NMEA sentences, it will read some of them, and then stop reading. ~47 characters every second, and it was getting like 3-10 seconds.

Looking at what it does with gdb (I have not yet followed too closely) it seems that nrf_serial_read function just returns nothing, and everything else keeps working.

It does this with and without the hardware flow control.

I tried increasing the buffer size, but it didn't seem to change the issue.

If I change the timeout parameter on nrf_serial_read to 0 (as documentation says it really should be in IRQ contexts), it actually reads less characters when you paste data.

https://infocenter.nordicsemi.com/topic/com.nordic.infocenter.sdk5.v15.0.0/group__nrf__serial.html#details

Am I using the example wrong, or is this a bug?

Parents Reply
  • "There is a bug where "use_easy_dma" which was removed from "nrf_drv_uart_config_t", is still used by "components/libraries/serial/nrf_serial.c" line 208"

    - use_easy_dma is still a member of nrf_drv_uart_config_t. See line 192 of  \integration\nrfx\legacy\nrf_drv_uart.h.

    You need to set the necessary defines in sdk_config.h or the preprocessor will not let the compiler use it. 

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