Using MIPI-DBI-SPI display and SPI sensor on same bus

[mnjLC]

Hello Nordic team,
We are trying to use ST7305 display (custom driver that we have developed using st7789V as refrence ) and acconeer A121 senors on same SPI bus. The A121 sensor works with no issues but the display does not work/update. If we completely remove the A121 sensor node and comment out the MISO pin then the display works perfectly fine. Can someone from nordic provide some insight on using the mipi-dbi-spi driver based display and simple spi based sesnor on same spi bus? I am sharing the overlay file with you

&spi3 {
	compatible = "nordic,nrf-spim";
	status = "okay";
	pinctrl-0 = <&spi3_default_alt>;
	pinctrl-1 = <&spi3_sleep_alt>;
	cs-gpios = <&gpio0 16 GPIO_ACTIVE_LOW>,<&gpio0 26 GPIO_ACTIVE_LOW>; #p0.16 is CS pin for display and p0.26 CS pin for A121 spi sensor 
	pinctrl-names = "default", "sleep";

	mipi_dbi_sT7305 {
        compatible = "zephyr,mipi-dbi-spi";
        spi-dev = <&spi3>;
        dc-gpios = <&gpio0 12 0 >;
        write-only;
        #address-cells = <1>;
		
        #size-cells = <0>;

        mydisplay2: st7305@0 {
            compatible = "zephyr,custom-st7305";
            status= "okay";
            mipi-max-frequency = <1000000>;
			mipi-mode = <0x02>;
            reg = <0x00>;
            width = <256>;
            height = <144>;
            x-offset = <0>;
            y-offset = <0>;
            nvm-param = [17 02];
            boost-param = <0x01>;
            gvctrl-param = [08 02];
            vshp-param = [41 41 41 41];
            vslp-param = [32 32 32 32];
            vshn-param = [4B 4B 4B 4B];
            vsln-param = [00 00 00 00];
            osc-param = [A6 E9];
            frctl-param = <0x13>;
            hpmctl-param = [E5 F6 05 46 77 77 77 77 76 45];
            lpmctl-param = [05 46 77 77 77 77 76 45];
            gatetm-param = [32 03 1F];
            srceq-param = <0x13>;
            gtline-param = <0x3F>;
            srcv-param = <0x00>;
            lpwr-param = [C1 41 26];
            caset-param = [19 23];
            raset-param = [00 7C];
            mdac = <0x00>;
            dfs-param = <0x11>;
            pset-param = <0x25>;
            enpwd-param = <0xFF>;
			// mipi-hold-cs;
        };
    };

	acc_a121_device: a121@1 {
		compatible = "acc,a121";
		reg = <0x01>;
		spi-max-frequency = <32000000>;
		status = "disabled";
	};
};

 

[Håkon Alseth]

Hi,

 

You shall define your mipi-node under the root-node, like shown here:

https://github.com/nrfconnect/sdk-zephyr/blob/v4.0.99-ncs1/boards/shields/seeed_xiao_round_display/seeed_xiao_round_display.overlay#L32-L49

 

And the amount of sensors on the chosen spi-node is determined how you declare that node. In the case of this specific board, it has 2 CSN pins, ie. 2 SPI slaves, defined:

https://github.com/nrfconnect/sdk-zephyr/blob/v4.0.99-ncs1/boards/shields/seeed_xiao_round_display/seeed_xiao_round_display.overlay#L84

Kind regards,

Håkon

[Dhruvil Levelcon]

hello Håkon

Thank You for your quick response.

Currently we have assigned a MISO Pin as a dc-gpio pin ( gpio0 12 )in our mipi-dbi-spi node for display. please do note that the same MISO pin is also used by our Sensor.

can we do that ?

&pinctrl {
    spi3_default_alt: spi3_default_alt {
        group1 {
            psels = <NRF_PSEL(SPIM_SCK, 0, 11)>,
                <NRF_PSEL(SPIM_MOSI, 0, 6)>,
                <NRF_PSEL(SPIM_MISO, 0, 12)>;
        };
    };

    spi3_sleep_alt: spi3_sleep_alt {
        group1 {
            psels = <NRF_PSEL(SPIM_SCK, 0, 11)>,
                <NRF_PSEL(SPIM_MOSI, 0, 6)>,
                <NRF_PSEL(SPIM_MISO, 0, 12)>;
            low-power-enable;
        };
    };
};

[Håkon Alseth]

Hi,

 

That will create a pin-conflict.

Try using different GPIOs for MISO/DC-pin and see if this helps.

 

Kind regards,

Håkon

[Dhruvil Levelcon]

Hello,

Thanks for quick response 

we cannot use a different pins as we are sharing a same spi bus and also we are short of pins on our controller.

So do you have any other options where we can use the same MISO pin?

Thanks

[Håkon Alseth]

Hi,

 

Dhruvil Levelcon said:

we cannot use a different pins as we are sharing a same spi bus

Sorry, but I do not understand. Why are you connecting DC to MISO? Those are two different purposes, and as pointed out; will create a conflict.

  

Kind regards,

Håkon