imx6q UART CTS/RTS Issue

[angelo_d]

Dear all,

i am using a kernel 3.10.17 on a board very similar to sabre-lite board.

I have an HCI/ BT module connected on uart2, that needs flow control.

After reset, the module sends on UART TX (imx6 RX) a train of data, scanning for firmware to be downloaded from bluez hciattach.

With pinmux settings for CTS and RTS commented out, i see the burst of data only on imx6 RX, as it should be, and i can upload the firmware successfully. Just after i have issues since the flow control is off.

If i enable pinmux ctrl pins for CTS and RTS, i see this burst of data in TX replicated on RX pin, RTS and CTS pins. And due to same train of data also in imx6 TX, i cannot upload the firmware anymore. Why this signal is now on all 4 UART pins ?

Thanks

Angelo

[mohammedazlum]

Hello,

Have you connected HCI BT modules directly into the iMX6 ?

Or Did you put any bridge between iMX6 CPU and youyr BCI BT ?

Regards,

Azlum

[marcocavallini]

Are your RTS/CTS signal working then?

[angelo_d]

Hi all,

thanks,

i had some linux devicetree issues mainly, something wrong in the syntax was not enabling really the flow control on those pins. Yes, now, with proper pinmux config, it works.

[marcocavallini]

Hi Angelo,

I still am struggling to make RS work.

Would you mind to share an excerpt of your DT please?

I am doing tese settings at the moment

https://community.freescale.com/thread/353966

[Yuri]

IMX6 UART has some specific implementation features. The i.MX6 DQ Reference

Manual provides clear description about internal signals and (external) multiplexing
for them. Table in the Datasheet helps to clarify it. Also - the following thread in Community
may be helpful.

"i.MX6: What does the DTE/DCE in i.MX6's UART do and how are RTS and CTS affected
by the UARTxUFCR[DTEDCE] bit?"

https://community.freescale.com/docs/DOC-97509#

Have a great day,
Yuri

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