i.MX ProcessorsのトピックMX6 UART KEY_COL1/ROW1 TXD/RXD can be swapped?

MX6 UART KEY_COL1/ROW1 TXD/RXD can be swapped?

raymondwang — Mon, 16 Sep 2013 06:35:49 GMT

Dear All, there are two IOMUX configurations

MX6Q_PAD_KEY_COL1__UART5_TXD ,MX6Q_PAD_KEY_COL1__UART5_RXD

MX6Q_PAD_KEY_ROW1__UART5_RXD , MX6Q_PAD_KEY_ROW1__UART5_TXD

Is that means we can swap uart5 TXD/RXD in the samp pins? If so, why I use latter configuration, It does not work?

Anybody had experience on MX6Q uart txd/rxd pin swap?

Re: MX6 UART KEY_COL1/ROW1 TXD/RXD can be swapped?

Yuri — Mon, 23 Sep 2013 06:09:48 GMT

According to section 36.4.125 “Pad Mux Register (IOMUXC_SW_MUX_CTL_PAD_KEY_ROW1)”,

“Pad KEY_ROW1 is involved in Daisy Chain”. This means in order to use ALT4 mode (UART5_RX_DATA)
it is needed additionally to “configure register IOMUXC_UART5_UART_RX_DATA_SELECT_INPUT
for mode ALT4”. Please look at section 36.4.587 “Select Input Register
(IOMUXC_UART5_UART_RX_DATA_SELECT_INPUT)” for more details.

Re: MX6 UART KEY_COL1/ROW1 TXD/RXD can be swapped?

raymondwang — Mon, 23 Sep 2013 11:40:26 GMT

Thanks for your reply!

Since IOMUX driver wrap all lowlevel details in linux, I use it in my Board pin config array.

static iomux_v3_cfg_t myboard_pads[] =

{

MX6Q_PAD_KEY_COL1__UART5_TXD,

MX6Q_PAD_KEY_ROW1__UART5_RXD,

};

Expand these two macros:

IOMUX_PAD(0x05D0, 0x0200, 4, 0x0000, 0, 0) | MUX_PAD_CTRL(MX6Q_UART_PAD_CTRL)

IOMUX_PAD(0x05D4, 0x0204, 4, 0x0940, 1, 0) | MUX_PAD_CTRL(MX6Q_UART_PAD_CTRL)

Bolded text is Daisy chain register offset and value

in my board_init:

mxc_iomux_v3_setup_multiple_pads(myboard_pads,

ARRAY_SIZE(myboard_pads));

Also,there are two Macros mapping to different uart TX/RX.

MX6Q_PAD_KEY_COL1__UART5_RXD

MX6Q_PAD_KEY_ROW1__UART5_TXD

Expand these two macros:

IOMUX_PAD(0x05D0, 0x0200, 4, 0x0940, 0, 0) || MUX_PAD_CTRL(MX6Q_UART_PAD_CTRL)

IOMUX_PAD(0x05D4, 0x0204, 4, 0x0000, 0, 0) | MUX_PAD_CTRL(MX6Q_UART_PAD_CTRL)

My question is if change to latter group pad config, my UART5 txd/rxd can be swapped?

If it can't ,why there are two more different macros which leading me to understand UART5 txd/rxd can be swapped?