cannot multiplex flexcan1 on LCD pins

[netfish]

Hello,

We are using i.mx6ul mpu and multiplexing flexcan1 on pins LCD_DATA08 & LCD_DATA09, but no luck.

dts changed as follows:

pinctrl_flexcan1: flexcan1grp{
    fsl,pins = <
        MX6UL_PAD_LCD_DATA08__FLEXCAN1_TX 0x1b020
        MX6UL_PAD_LCD_DATA09__FLEXCAN1_RX 0x1b020
    >;
};

No signal occurs on the LCD_DATA08 pin when can sending, checked using oscilloscope.

What issue can it be? Any special care should be taken when using LCD pins?

We are stuck on this for nearly a week.  Any response is appreciated.

Thanks,

Edwin

[igorpadykov]

Hi Edwin

i.MX6UL flexcan1 example can be found on

linux/arch/arm/boot/dts/imx6ul-14x14-evk.dts

imx6ul-14x14-evk.dts\dts\boot\arm\arch - linux-imx - i.MX Linux kernel 

One can check if these lcd MX6UL_PAD_LCD_DATA08 pads were not used

by other modules. Also recommended to testing attach another board, otherwise

you may will not see flexcan signals.

Best regards
igor
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[netfish]

Hi igor,

Thanks for your reply.

We have double checked. No othrer moudle use these pins. 

We have tried to route flexcan1_tx to other pins, it is OK.

Our board is mostly compatible with NXP official IMX6UL-EVK.

LCD_DATA08 is attached directly to can receiver with a 10k pull-down resistor for boot.

Are there any special power or clock settings needed?

pinctrl_flexcan1: flexcan1grp{
fsl,pins = <
//MX6UL_PAD_UART3_RTS_B__FLEXCAN1_RX 0x1b020
//MX6UL_PAD_UART3_CTS_B__FLEXCAN1_TX 0x1b020
MX6UL_PAD_LCD_DATA08__FLEXCAN1_TX 0x1b020
MX6UL_PAD_LCD_DATA09__FLEXCAN1_RX 0x1b020
//MX6UL_PAD_SD1_DATA0__FLEXCAN1_TX 0x1b020
//MX6UL_PAD_SD1_DATA1__FLEXCAN1_RX 0x1b020
>;
};

pinctrl_lcdif_dat: lcdifdatgrp {
fsl,pins = <
MX6UL_PAD_LCD_DATA00__LCDIF_DATA00 0x79
MX6UL_PAD_LCD_DATA01__LCDIF_DATA01 0x79
MX6UL_PAD_LCD_DATA02__LCDIF_DATA02 0x79
MX6UL_PAD_LCD_DATA03__LCDIF_DATA03 0x79
MX6UL_PAD_LCD_DATA04__LCDIF_DATA04 0x79
MX6UL_PAD_LCD_DATA05__LCDIF_DATA05 0x79
MX6UL_PAD_LCD_DATA06__LCDIF_DATA06 0x79
MX6UL_PAD_LCD_DATA07__LCDIF_DATA07 0x79
//MX6UL_PAD_LCD_DATA08__LCDIF_DATA08 0x79
//MX6UL_PAD_LCD_DATA09__LCDIF_DATA09 0x79
MX6UL_PAD_LCD_DATA10__LCDIF_DATA10 0x79
MX6UL_PAD_LCD_DATA11__LCDIF_DATA11 0x79
MX6UL_PAD_LCD_DATA12__LCDIF_DATA12 0x79
MX6UL_PAD_LCD_DATA13__LCDIF_DATA13 0x79
MX6UL_PAD_LCD_DATA14__LCDIF_DATA14 0x79
MX6UL_PAD_LCD_DATA15__LCDIF_DATA15 0x79
MX6UL_PAD_LCD_DATA16__LCDIF_DATA16 0x79
MX6UL_PAD_LCD_DATA17__LCDIF_DATA17 0x79
MX6UL_PAD_LCD_DATA18__LCDIF_DATA18 0x79
MX6UL_PAD_LCD_DATA19__LCDIF_DATA19 0x79
MX6UL_PAD_LCD_DATA20__LCDIF_DATA20 0x79
MX6UL_PAD_LCD_DATA21__LCDIF_DATA21 0x79
MX6UL_PAD_LCD_DATA22__LCDIF_DATA22 0x79
MX6UL_PAD_LCD_DATA23__LCDIF_DATA23 0x79
>;
};

Any advice?

Thanks,

Edwin

[zzyhqu]

Hi Edwin ,

did you resolve your problem and how to resolve it ? I also meet the same problem

[netfish]

Hi xm,

No. We just rebuilt our board and route the can to uart3 rts/cts.

[igorpadykov]

Hi Edwin

lcd can be used in uboot splashscreen, so one can try to disable these pins

in uboot too, please check iomux_v3_cfg_t const lcd_pads[]:
mx6ul_14x14_evk.c\mx6ul_14x14_evk\freescale\board - uboot-imx - i.MX U-Boot 

Also as signal LCDIF_DATA08 has not alternative mux option except from pad

MX6UL_PAD_LCD_DATA08__LCDIF_DATA08, seems one can disable lcd completely.

Best regards
igor