Sending via Uart

[kagislason]

Hi, I need to be able to communicate between two boards via UART. I had a look at the example from Ole provided here: devzone.nordicsemi.com/.../ as well as other references here on the Dev zone and code examples in the SDK.

I am running the PCA10001 and also tested it on the N5 chip from Dynastream. The chip is using SDK v6.1 and SD s110 v7.

I need to use hardware flowcontrol and to simplify things I am currently testing it against a PC. Using Ole's code and importing it into a clean IAR project and running it on the PCA10001 the software goes into the app_error_handler after trying to run app_uart_put for the second time, the reason is a NRF_ERROR_NO_MEM error as the current state is not UART_READY. This happens for both HFC on/off.

uint8_t len = strlen((char *) str);
for (uint8_t i = 0; i < len; i++)
{
    APP_ERROR_CHECK(app_uart_put(str[i]));
}

Here is a copy of the app_uart_put function from app_uart.c

uint32_t app_uart_put(uint8_t byte){
    uint32_t err_code = NRF_SUCCESS;

    if (m_current_state != UART_READY)
    {
      err_code = NRF_ERROR_NO_MEM;
    }
    else
    {
      m_tx_byte = byte;
      on_uart_event(ON_UART_PUT);
    }

    return err_code;
}

By adding something like this into the app_uart_put function the problem is solved but I would rather not want to change the SDK. Could also put a fixed delay into the send function but that is an even worse hack in my opinion.

while (m_current_state != UART_READY)
{
    // Wait until uart is ready again
}

Am I using the framework incorrectly or can someone suggest a cleaner solution for this issue, the best thing would be to be able to use the app_uart library from the SDK without modification for future releases.

Thanks!

[Asbjørn]

Which version of the nRF51822 are you using. There was an increase in the UART buffers between revision 1 and revision 2 of the chip from 2 byte to 6 bytes.

nRF51822 QFAAC0 is first revision. nRF51822 QFAAG0 is second revision.

You have at least two nRF51822 or are you planning on having two different UART chips talking to each other? What's the setup you are actually looking for?

[kagislason]

Currently using the N5 chip from Dynastream which is based on the nRF51422. I did not find which revision they are basing their chip on but I did also try the same with other Nordic evaluation kits (using the corresponding libraries of course) with no luck. I have a few evaluation kits from Nordic (both 51822 and 51422, e.g. PCA10001, PCA10003 and more) and also the N5 chip from Dynastream (M8CB based on nRF51422) which I could also test this on if necessary.

The end product will be the N5 chip communicating over UART to a LPC1769 from NXP. Using the LPC as the main processing unit and the N5 chip for BLE communication in the platform.

To simplify things I am currently testing this against my PC using a UB232R serial module and a logical analyzer.