About SDMA support for UART in i.MX6DQ.

[keitanagashima]

Dear Sir or Madam,

Hello.

Refer to "46.1 Introduction" in i.MX 6 Linux Reference Manual, Rev. L3.10.17_1.0.0-ga, 05/2014

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If you want to use the DMA support for UART please also

enable the RTS/CTS for it. The DMA may be abnormal if you

do not enable the RTS/CTS.

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I'd like to know the why FSL judged that RTS/CTS need.

(My customer will use SDMA with UART that do not enable the RTS/CTS.)

What problem did freescale face in the past?

Best Regards,

Keita

[Yuri · Accepted solution]

  UART interface is relatively slow, therefore special lines are required

for hardware ready acknowledgement, in order to avoid data FIFO overrun.

Have a great day,
Yuri

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[keitanagashima]

Hi Yuri,

Thank you for your answer.

I understood the reason.

Best Regards,

Keita