topic Re: SDK 2.1 UART Rx Overflow handling bug in MCUXpresso SDK

SDK 2.1 UART Rx Overflow handling bug

paulsandys — Sat, 18 Feb 2017 06:37:56 GMT

I think there's a logical bug in fsl_uart.c

/* If RX overrun. */

if (UART_S1_OR_MASK & base->S1) {
/* Read base->D to clear overrun flag, otherwise the RX does not work. */
while (base->S1 & UART_S1_RDRF_MASK) {
(void) base->D;
}

The "while (base->S1 & UART_S1_RDRF_MASK)" creates a problem when the routine gets preempted by another interrupt. The RDRF can be set again, causing the routine to eat up extra bytes and/or generate additional Rx OR interrupts. After removing the while loop and reading "(void) base->D;" exactly once, the problems go away.

Re: SDK 2.1 UART Rx Overflow handling bug

Alice_Yang — Tue, 07 Mar 2017 07:43:32 GMT

Hello Paul,

Which chip do you used?

I randomly check one SDK package (FRDM-K22),

it just read D once :

Alice

Re: SDK 2.1 UART Rx Overflow handling bug

paulsandys — Tue, 07 Mar 2017 18:13:11 GMT

FRDM-KL25Z

Re: SDK 2.1 UART Rx Overflow handling bug

Alice_Yang — Wed, 08 Mar 2017 05:31:38 GMT

Hello ,

Thanks for your sharing , I will report it to the SDK team.

And I recommend you can use the UART driver file of FRDM-KL26.

I also attached it for you.

Hope it helps

Alice

Re: SDK 2.1 UART Rx Overflow handling bug

paulsandys — Wed, 15 Mar 2017 05:43:36 GMT

I've wrote my own IRQ handler.

It would be very useful if the UART async driver could callback after receiving "special" character specified in the xfer structure, similar to SPI. (I.E. NewLine, CarriageReturn, NULL or whatever)

Re: SDK 2.1 UART Rx Overflow handling bug

NicolasP — Fri, 14 Sep 2018 13:20:05 GMT

Hi,

Same problem with SDK 2.4.1 and K22FN51212

Best regards,

Nicolas

Re: SDK 2.1 UART Rx Overflow handling bug

biafra — Wed, 12 Dec 2018 10:06:10 GMT

Hi Alice_Yang‌,

It's the same in the latest SDK for TWR-K65F180M (2.4.1 2018-09-14).

Many thanks

Biafra