topic Re: Timeouts in LPUART with FreeRTOS in MCUXpresso General

Timeouts in LPUART with FreeRTOS

andrew_walsh — Thu, 31 Jan 2019 09:05:08 GMT

Hello,

I'm currently planning to use the LPUART FreeRTOS driver (fsl_lpuart_freertos.*) from the MCUXpresso SDK, but I've noticed that it is not possible to specify a timeout. This appears to be the case in 2.5.0, which I think is the latest (dated 11th Jan 2019).

For example, inside the function LPUART_RTOS_Send(), there is a call to LPUART_TransferSendNonBlocking(), followed by a call to the FreeRTOS xEventGroupWaitBits(), which is as I might expect. The problem, however, is that a hardcoded value, portMAX_DELAY is passed for the parameter xTicksToWait, which I think means it will wait forever.

Would NXP consider modifying the SDK, providing an extra parameter to LPUART_RTOS_Send() which would allow this wait time to be specified? If xEventGroupWaitBits() then returns with no event bits set, LPUART_RTOS_Send() would call LPUART_TransferAbortSend(), perhaps?

If this change was made, I think similar modifications would also be needed in LPUART_RTOS_Receive().

Many Thanks,

Andrew.

Re: Timeouts in LPUART with FreeRTOS

BlackNight — Thu, 31 Jan 2019 17:58:16 GMT

Hi Andrew,

you might have a look at the files in mcuoneclipse/uart.c at master · GitHub

where it implements a simple non-blocking UART driver with FreeRTOS.

I hope this helps,

Erich

Re: Timeouts in LPUART with FreeRTOS

andrew_walsh — Mon, 11 Feb 2019 07:56:26 GMT

Hi Erich,

Thanks for this, and sorry for the delay of my reply; I'll take a look.

I am thinking, in any case, that I'll have to modify the MCUXpresso API, but I was hoping that NXP would consider modifying the standard API.

Best regards,

Andrew.

Re: Timeouts in LPUART with FreeRTOS

danielchen — Mon, 18 Feb 2019 15:09:11 GMT

Hi Andrew:

Thanks for your good suggestion, I will issue a feature request to the develop team.

Regards

Daniel

Re: Timeouts in LPUART with FreeRTOS

Meera_123 — Fri, 19 Mar 2021 10:32:32 GMT

Hiii I tried your code https://github.com/ErichStyger/mcuoneclipse/blob/f2a1361e8a49cc0a2428618796fde21d559cc304/Examples/MCUXpresso/i.MX%20RT1064_EVK/MIMXRT1064_FreeRTOS/source/uart.c

void UART_Init(void) { MSG_Init(); if (xTaskCreate(UartTask, /* pointer to the task */ "UartTask", /* task name for kernel awareness debugging */ 500/sizeof(portSTACK_TYPE), /* task stack size */ NULL, /* optional task startup argument */ tskIDLE_PRIORITY+1, /* initial priority */ NULL /* optional task handle to create */ ) != pdPASS) { for(;;) {} } MSG_SendStringTxQueue("AT\r"); MSG_SendStringTxQueue("AT+CSQ\r"); }

Then it transmits both the string together("AT\rAT+CSQ\r"). I checked here MSG_GetStringTxQueue(localBuf, sizeof(localBuf)); and gives response of first string.