i.MX ProcessorsのトピックRe: Question, i.MX6 UART re-initialization

Question, i.MX6 UART re-initialization

Aemj — Thu, 09 Oct 2014 05:16:24 GMT

Dear TIC team,

I would like to ask about re-initializing of i.MX6 UART.

My customer is using i.MX6S UART and they need to change UART settings in their application.

When they implemented the re-initialization software without disabling interrupt, they saw the UART did not work as expected after the re-init due to the behavior of interrupt.

Then they added disabling RX interrupt before the re-init process, and UART worked fine after the re-init.

Could you show me whether the adding disabling RX int right before the re-init is reasonable?

Thanks,

Miyamoto

Re: Question, i.MX6 UART re-initialization

igorpadykov — Thu, 09 Oct 2014 14:18:17 GMT

Hi AVNET JAPAN FAE

what UART bits they changed during "re-init process",

had UARTEN, RXEN changed?

Best regards

igor

Re: Question, i.MX6 UART re-initialization

Aemj — Fri, 10 Oct 2014 00:12:36 GMT

Hi Igor,

Baudrate and length of stop-bit were changed.

BR,

Miyamoto

Re: Question, i.MX6 UART re-initialization

igorpadykov — Sat, 11 Oct 2014 14:39:38 GMT

Hi AVNET JAPAN FAE

seems it may be caused below

Re: i.MX6 UART hardware misbehaves on baudrate mismatch

fixed if bit 7 of UCR3 (ADNIMP in the reference manual) is set.

Best regards

igor

Re: Question, i.MX6 UART re-initialization

fabio_estevam — Sat, 11 Oct 2014 22:37:59 GMT

Miyamoto,

Could you please tell which OS is your customer using and also:

- The exact steps to reproduce the problem?

- The patch with their fix

Thanks

Re: Question, i.MX6 UART re-initialization

Aemj — Tue, 14 Oct 2014 02:02:54 GMT

Hi Fabio,

OS: i-Tron base

Re-init procedure:

HW_UART_UCR1_CLR(instance,BM_UART_UCR1_RRDYEN); // disable UART RX interrupt

uart_init( instance, baudrate, PARITY_NONE, stopbits, EIGHTBITS, FLOWCTRL_OFF );

uart_set_FIFO_mode( instance, RX_FIFO, 1, IRQ_MODE );

Without the 1st step, disabling RX int, the re-init does not work fine.

Without disabling rx int, interrupt seems to occur repeatedly after the re-init.

the uart_init() function came from your SDK.

BR,

Miyamoto

Re: Question, i.MX6 UART re-initialization

Aemj — Fri, 17 Oct 2014 08:33:04 GMT

Hi Fabio,

The customer wants to clarify whether the disabling interrupt is needed when changing UART settings(baud-rate, stop-bit length change).

Do you think the disabling int is not needed always?

BR,

Miyamoto

Re: Question, i.MX6 UART re-initialization

fabio_estevam — Fri, 17 Oct 2014 13:14:47 GMT

Hi Miyamoto,

I thought initially your customer was using linux, but this issue I have never seen with linux.

I am not familiar with SDK or i-Tron OS, sorry.

Regards,

Fabio Estevam