IMX6DL In Yocto UART3 with CTS and RTS configure

[wenjingwang]

HW Env:   IMX6DL

SF  Env:  Yocto (Kernel version 3.10.7)

I connect the BT module with UART3(with CTS and RTS), the PIN ctrl is like the flow:

UART3_CTS<-------->EIM_D30     (mux_reg = 0x4;   pad_reg  = 0x130b1)

UART3_RTS<-------->EIM_D31     (mux_reg = 0x4;   pad_reg  = 0x130b1)

UART3_RXD<-------->EIM_D25     (mux_reg = 0x2;   pad_reg  = 0x1b0b1)

UART3_TXD<-------->EIM_D24     (mux_reg = 0x2;   pad_reg  = 0x1b0b1)

the daisy is configured already:

IOMUXC_UART3_UART_RTS_B_SELECT_INPUT           reg = 0x2

IOMUXC_UART3_UART_RX_DATA_SELECT_INPUT      reg = 0x1

I tested the BT module with another uart(ttyUSB0)and it work ok when it connected the ttyUSB0 uart, so think the BT module is OK.

when i connect the BT to UART3(ttymxc2),and  powered up, then use the bt-app write data to uart3 and the BT-CTS and BT-RXD pin is high level without any change, like this:

then Ctrl+C the bt-app, and try again, the BT-CTS is low and data can be transfer on BT-RXD, but sometimes failed in transfering, if success the BT-CTS will hight(int ttyUSB0, the BT-CTS will be hold low), like this:

[Yuri]

   Please refer to the following regarding i.MX6 UART specifics.

"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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