My nRF51822 can not reach 1MBaud on an UART serial UART communication

RE: My nRF51822 can not reach 1MBaud on an UART serial UART communication

Hung Bui — Tue, 30 May 2017 09:18:20 GMT

Hi,

I mean the limitation of the hardware on PC. I attached here the test program I used. It's made on SDK v7.x but should run on other SDK as well (with minor change). Put it to example\peripheral to test.

uart - TestThrougput.zip

RE: My nRF51822 can not reach 1MBaud on an UART serial UART communication

Antrou — Mon, 29 May 2017 13:26:20 GMT

@Hung Bui: What do you mean by limitation of the hardware ? Something we did wrong on our custom board or limitation of computer ? On which system did you try your test ? Did you use nrf51 DK or another board ? How did you reach 89kB/s ? Thank you

RE: My nRF51822 can not reach 1MBaud on an UART serial UART communication

Hung Bui — Tue, 23 May 2017 14:20:53 GMT

@Antrou: I would assume you have the issue because of the limitation of the hardware, it takes time between each transaction to clock out the next byte. A logic analyzer can reveal if you have any delay before you can clock the next byte. In my test here I can see the through put of 89KB/s when using with 1Mbps.

RE: My nRF51822 can not reach 1MBaud on an UART serial UART communication

Hung Bui — Tue, 16 May 2017 14:38:04 GMT

@Antrou: You can send me via private message here. Or you can create a support portal (MyPage) case on our website.

To start HF crystal you can use this code:

/* Start 16 MHz crystal oscillator */
NRF_CLOCK->EVENTS_HFCLKSTARTED = 0;
NRF_CLOCK->TASKS_HFCLKSTART    = 1;

/* Wait for the external oscillator to start up */
while (NRF_CLOCK->EVENTS_HFCLKSTARTED == 0)
{
    // Do nothing.
}

Have you tried to use 2 nRF5 boards to talk to each other ?

RE: My nRF51822 can not reach 1MBaud on an UART serial UART communication

Antrou — Tue, 16 May 2017 13:04:53 GMT

Our 32MHz crystal is external

RE: My nRF51822 can not reach 1MBaud on an UART serial UART communication

Antrou — Tue, 16 May 2017 13:03:21 GMT

How can I send you my test firmware ? What is the more suitable for you ? I tried it on 3 differents PCB and the result remains the same. We have a 32MHz crystal on our boards, how can I configure the UART driver in order to use Crystal instead of RC. Thank you

RE: My nRF51822 can not reach 1MBaud on an UART serial UART communication

Hung Bui — Fri, 12 May 2017 11:24:05 GMT

Can you send me the test firmware you used ? An test to rule out the issue with the computer is to use another nRF51822 to talk to your board. If you have 2 nRF51 board, please try to test. Do you have the 16MHz crystal on your board ? You may want to turn on the 16MHz external crystal instead of using the RC. The RC has pretty high tolerance.

RE: My nRF51822 can not reach 1MBaud on an UART serial UART communication

Antrou — Thu, 11 May 2017 13:13:51 GMT

Hello,

I am currently using app_uart_put() and app_uart_get() functions with macro APP_UART_INIT as initialization. I only tried our serial speed test on our custom PCB(not DK or dongle) with a nRF51822 processor. I also tried to compute it on another computer but the result remains the same (300 kBaud instead of 1MBaud).

My code and script (which sends/ receives data and compute transfer speed) work really well until 250kBaud, when I try to increase the speed it gets worse and worse ... Any clue will be appreciated :) Thank you for your help.

RE: My nRF51822 can not reach 1MBaud on an UART serial UART communication

Hung Bui — Thu, 27 Apr 2017 10:55:56 GMT

@antrou: Which UART driver you used on the board to communicate with the PC ? Did you test with our nRF51 DK or Dongle ? Our nRFConnect software running on PC use 1Mbps baudrate to communicate with the NRF51 dongle without a problem.

Have you tried on other computer ? I experienced that on some computer 1Mbps baudrate actually not supported.