MHS35 (ILI9486) variant

[craigerl]

EDIT
CORRECTION - The Device in question is the MHS35 not the MHS35B
EDIT

I de-compiled the device tree overlay for the "MHS35b" ili9486 variant, which is a popular alternative to the increasingly hard-to-find Waveshare ili9486 which works perfectly with this python driver.

This is in the hope it might trigger an obvious tweak to your project to get it to work. The initialize command bytes are very similar.

https://github.com/goodtft/LCD-show/blob/master/MHS35B-show

$ cat mhs35b-overlay.dts

/dts-v1/;

/ {
        compatible = "brcm,bcm2835\0brcm,bcm2708\0brcm,bcm2709";

        fragment@0 {
                target = <0xffffffff>;

                __overlay__ {
                        status = "okay";

                        spidev@0 {
                                status = "disabled";
                        };

                        spidev@1 {
                                status = "disabled";
                        };
                };
        };

        fragment@1 {
                target = <0xffffffff>;

                __overlay__ {

                        tft35a_pins {
                                brcm,pins = <0x19 0x18>;
                                brcm,function = <0x00 0x00>;
                                phandle = <0x01>;
                        };
                };
        };

        fragment@2 {
                target = <0xffffffff>;

                __overlay__ {
                        #address-cells = <0x01>;
                        #size-cells = <0x00>;

                        tft35a@0 {
                                compatible = "ilitek,ili9486";
                                reg = <0x00>;
                                pinctrl-names = "default";
                                pinctrl-0 = <0x01>;
                                spi-max-frequency = <0x8f0d180>;
                                txbuflen = <0x8000>;
                                rotate = <0x5a>;
                                bgr = <0x00>;
                                fps = <0x1e>;
                                buswidth = <0x08>;
                                regwidth = <0x10>;
                                reset-gpios = <0xffffffff 0x19 0x01>;
                                dc-gpios = <0xffffffff 0x18 0x00>;
                                debug = <0x00>;
                                init = <0x10000f1 0x36 0x04 0x00 0x3c 0x0f 0x8f 0x10000f2 0x18 0xa3 0x12 0x02 0xb2 0x12 0xff 0x10 0x00 0x10000f8 0x21 0x04 0x10000f9 0x00 0x08 0x1000036 0x08 0x10000b4 0x00 0x10000c1 0x41 0x10000c5 0x00 0x91 0x80 0x00 0x10000e0 0x0f 0x1f 0x1c 0x0c 0x0f 0x08 0x48 0x98 0x37 0x0a 0x13 0x04 0x11 0x0d 0x00 0x10000e1 0x0f 0x32 0x2e 0x0b 0x0d 0x05 0x47 0x75 0x37 0x06 0x10 0x03 0x24 0x20 0x00 0x100003a 0x55 0x1000011 0x1000036 0x28 0x20000ff 0x1000029>;
                                phandle = <0x02>;
                        };
                };
        };

        __overrides__ {
                speed = <0x02 0x7370692d 0x6d61782d 0x66726571 0x75656e63 0x793a3000>;
                txbuflen = [00 00 00 02 74 78 62 75 66 6c 65 6e 3a 30 00];
                rotate = [00 00 00 02 72 6f 74 61 74 65 3a 30 00];
                fps = [00 00 00 02 66 70 73 3a 30 00];
                bgr = [00 00 00 02 62 67 72 3a 30 00];
                debug = <0x02 0x64656275 0x673a3000>;
        };

        __fixups__ {
                spi0 = "/fragment@0:target:0\0/fragment@2:target:0";
                gpio = "/fragment@1:target:0\0/fragment@2/__overlay__/tft35a@0:reset-gpios:0\0/fragment@2/__overlay__/tft35a@0:dc-gpios:0";
        };

        __local_fixups__ {

                fragment@2 {

                        __overlay__ {

                                tft35a@0 {
                                        pinctrl-0 = <0x00>;
                                };
                        };
                };

                __overrides__ {
                        speed = <0x00>;
                        txbuflen = <0x00>;
                        rotate = <0x00>;
                        fps = <0x00>;
                        bgr = <0x00>;
                        debug = <0x00>;
                };
        };
};

[SirLefti]

Hi mate, long time no see.

I am not sure how I can work on that, because I do not own that display module. If you got a working patch, I'd be probably able to assist you in bringing it together in the same code base, if it makes sense to do so.

I think this is related to #4 right?

I developed this lib using the ILI9486 spec sheet. I see an init sequence in the file you shared, but I an not sure what it tells me.

[craigerl]

Thanks again for all the support here - great work.

I just noticed the string of bytes for "Initialize" was very similar (almost identical) in both the dtoverlay and your ili9486 driver here. I'll keep poking at it, but will otherwise leave the dtoverlay here in case somebody thinks of a way to integrate it with this project.

best,
-craig

[SirLefti]

Yes, I see some similarities. Do you see the 0x10000e0 and 0x10000e1 with their following data? e0 and e1 are the positive and negative gamma control commands (PGAMCTL and NGAMCTL) in ILI9486. They are most likely the same thing here as well. But the other commands not known to me, and they do not appear in the spec sheet I used to implement the commands back then.

If you want to try your luck, all 0x10000.. bytes are most likely commands, the shorter ones are data. You can change the init sequence and see if it works. For the commands, you can maybe use just the last two digits and ignore the long 0x10000 part, not sure about that.

[snakefood3232]

The device tree overlay you mentioned for the MHS35b ILI9486 variant has similarities that could be leveraged to tweak the existing driver. I'd handle this by examining the initialization command bytes and adjusting the driver accordingly to accommodate these differences. Can have a PR up within 2 days. I've worked on similar integrations with SPI-based displays, ensuring compatibility across various hardware variations.

[craigerl]

I thought you might have some good insights. I went a few bytes into the init string on the dtoverlay and started picking out LOTS of consecutive similarities. I can send you a screen too. thanks,
-craig

[craigerl]

According to amazon reviews the MHS35-show driver doesn't work, however the LCD35-show driver does, in fact, work, so posting that device tree here. Screen specs,

https://www.lcdwiki.com/MHS-3.5inch_RPi_Display

tft35a-overlay.dtb

/dts-v1/;                                                                                                                
                                                                                                                         
/ {                                                                                                                      
        compatible = "brcm,bcm2835\0brcm,bcm2708\0brcm,bcm2709";                                                         
                                                                                                                         
        fragment@0 {                                                                                                     
                target = <0xdeadbeef>;                                                                                   
                                                                                                                         
                __overlay__ {                                                                                            
                        status = "okay";                                                                                 
                                                                                                                         
                        spidev@0 {                                                                                       
                                status = "disabled";                                                                     
                        };                                                                                               
                                                                                                                         
                        spidev@1 {                                                                                       
                                status = "disabled";                                                                     
                        };                                                                                               
                };                                                                                                       
        };                                                                                                               
                                                                                                                         
        fragment@1 {
                target = <0xdeadbeef>;

                __overlay__ {

                        tft35a_pins {
                                brcm,pins = <0x11 0x19 0x18>;
                                brcm,function = <0x00 0x00 0x00>;
                                linux,phandle = <0x01>;
                                phandle = <0x01>;
                        };
                };
        };

        fragment@2 {
                target = <0xdeadbeef>;

                __overlay__ {
                        #address-cells = <0x01>;
                        #size-cells = <0x00>;

                        tft35a@0 {
                                compatible = "ilitek,ili9486";
                                reg = <0x00>;
                                pinctrl-names = "default";
                                pinctrl-0 = <0x01>;
                                spi-max-frequency = <0xf42400>;
                                txbuflen = <0x8000>;
                                rotate = <0x5a>;
                                bgr = <0x00>;
                                fps = <0x1e>;
                                buswidth = <0x08>;
                                regwidth = <0x10>;
                                reset-gpios = <0xdeadbeef 0x19 0x01>;
                                dc-gpios = <0xdeadbeef 0x18 0x00>;
                                debug = <0x00>;
                                init = <0x10000f1 0x36 0x04 0x00 0x3c 0x0f 0x8f 0x10000f2 0x18 0xa3 0x12 0x02 0xb2 0x12 0xff 0x10 0x00 0x10000f8 0x21 0x04 0x10000f9 0x00 0x08 0x1000036 0x08 0x10000b4 0x00 0x10000c1 0x41 0x10000c5 0x00 0x91 0x80 0x00 0x10000e0 0x0f 0x1f 0x1c 0x0c 0x0f 0x08 0x48 0x98 0x37 0x0a 0x13 0x04 0x11 0x0d 0x00 0x10000e1 0x0f 0x32 0x2e 0x0b 0x0d 0x05 0x47 0x75 0x37 0x06 0x10 0x03 0x24 0x20 0x00 0x100003a 0x55 0x1000011 0x1000036 0x28 0x20000ff 0x1000029>;
                                linux,phandle = <0x02>;
                                phandle = <0x02>;
                        };

                        tft35a-ts@1 {
                                compatible = "ti,ads7846";
                                reg = <0x01>;
                                spi-max-frequency = <0x1e8480>;
                                interrupts = <0x11 0x02>;
                                interrupt-parent = <0xdeadbeef>;
                                pendown-gpio = <0xdeadbeef 0x11 0x01>;
                                ti,x-plate-ohms = [00 3c];
                                ti,pressure-max = [00 ff];
                                linux,phandle = <0x03>;
                                phandle = <0x03>;
                        };
                };
        };

        __overrides__ {
                speed = <0x02 0x7370692d 0x6d61782d 0x66726571 0x75656e63 0x793a3000>;
                txbuflen = [00 00 00 02 74 78 62 75 66 6c 65 6e 3a 30 00];
                rotate = [00 00 00 02 72 6f 74 61 74 65 3a 30 00];
                fps = [00 00 00 02 66 70 73 3a 30 00];
                bgr = [00 00 00 02 62 67 72 3a 30 00];
                debug = <0x02 0x64656275 0x673a3000>;
                swapxy = <0x03 0x74692c73 0x7761702d 0x78793f00>;
        };

        __symbols__ {
                tft35a_pins = "/fragment@1/__overlay__/tft35a_pins";
                tft35a = "/fragment@2/__overlay__/tft35a@0";
                tft35a_ts = "/fragment@2/__overlay__/tft35a-ts@1";
        };

        __fixups__ {
                spi0 = "/fragment@0:target:0\0/fragment@2:target:0";
                gpio = "/fragment@1:target:0\0/fragment@2/__overlay__/tft35a@0:reset-gpios:0\0/fragment@2/__overlay__/tft35a@0:dc-gpios:0\0/fragment@2/__overlay__/tft35a-ts@1:interrupt-parent:0\0/fragment@2/__overlay__/tft35a-ts@1:pendown-gpio:0";
        };

        __local_fixups__ {
                fixup = "/fragment@2/__overlay__/tft35a@0:pinctrl-0:0\0/__overrides__:speed:0\0/__overrides__:txbuflen:0\0/__overrides__:rotate:0\0/__overrides__:fps:0\0/__overrides__:bgr:0\0/__overrides__:debug:0\0/__overrides__:swapxy:0";
        };
};

[craigerl]

And the manufacturer recommended device tree overlay from https://www.lcdwiki.com/MHS-3.5inch_RPi_Display

mhs35-overlay.dts

/dts-v1/;

/ {
        compatible = "brcm,bcm2835\0brcm,bcm2708\0brcm,bcm2709";

        fragment@0 {
                target = <0xdeadbeef>;

                __overlay__ {
                        status = "okay";

                        spidev@0 {
                                status = "disabled";                            
                        };                                                      
                                                                                
                        spidev@1 {                                              
                                status = "disabled";                            
                        };                                                      
                };                                                              
        };                                                                      
                                                                                
        fragment@1 {                                                            
                target = <0xdeadbeef>;                                          
                                                                                
                __overlay__ {                                                   
                                                                                
                        tft35a_pins {                                           
                                brcm,pins = <0x11 0x19 0x18>;                   
                                brcm,function = <0x00 0x00 0x00>;               
                                linux,phandle = <0x01>;                         
                                phandle = <0x01>;                               
                        };                                                      
                };                                                              
        };                                                                      
                                                                                
        fragment@2 {                                                            
                target = <0xdeadbeef>;                                          
                                                                                
                __overlay__ {                                                   
                        #address-cells = <0x01>;                                
                        #size-cells = <0x00>;                                   
                                                                                
                        tft35a@0 {                                              
                                compatible = "ilitek,ili9486";                  
                                reg = <0x00>;                                   
                                pinctrl-names = "default";                      
                                pinctrl-0 = <0x01>;                             
                                spi-max-frequency = <0x6dac2c0>;
                                txbuflen = <0x8000>;
                                rotate = <0x5a>;
                                bgr = <0x00>;
                                fps = <0x1e>;
                                buswidth = <0x08>;
                                regwidth = <0x10>;
                                reset-gpios = <0xdeadbeef 0x19 0x01>;
                                dc-gpios = <0xdeadbeef 0x18 0x00>;
                                debug = <0x00>;
                                init = <0x10000f1 0x36 0x04 0x00 0x3c 0x0f 0x8f 0x10000f2 0x18 0xa3 0x12 0x02 0xb2 0x12 0xff 0x10 0x00 0x10000f8 0x21 0x04 0x10000f9 0x00 0x08 0x1000036 0x08 0x10000b4 0x00 0x10000c1 0x41 0x10000c5 0x00 0x91 0x80 0x00 0x10000e0 0x0f 0x1f 0x1c 0x0c 0x0f 0x08 0x48 0x98 0x37 0x0a 0x13 0x04 0x11 0x0d 0x00 0x10000e1 0x0f 0x32 0x2e 0x0b 0x0d 0x05 0x47 0x75 0x37 0x06 0x10 0x03 0x24 0x20 0x00 0x100003a 0x55 0x1000011 0x1000036 0x28 0x20000ff 0x1000029>;
                                linux,phandle = <0x02>;
                                phandle = <0x02>;
                        };

                        tft35a-ts@1 {
                                compatible = "ti,ads7846";
                                reg = <0x01>;
                                spi-max-frequency = <0x1e8480>;
                                interrupts = <0x11 0x02>;
                                interrupt-parent = <0xdeadbeef>;
                                pendown-gpio = <0xdeadbeef 0x11 0x01>;
                                ti,x-plate-ohms = [00 3c];
                                ti,pressure-max = [00 ff];
                                linux,phandle = <0x03>;
                                phandle = <0x03>;
                        };
                };
        };

        __overrides__ {
                speed = <0x02 0x7370692d 0x6d61782d 0x66726571 0x75656e63 0x793a3000>;
                txbuflen = [00 00 00 02 74 78 62 75 66 6c 65 6e 3a 30 00];
                rotate = [00 00 00 02 72 6f 74 61 74 65 3a 30 00];
                fps = [00 00 00 02 66 70 73 3a 30 00];
                bgr = [00 00 00 02 62 67 72 3a 30 00];
                debug = <0x02 0x64656275 0x673a3000>;
                swapxy = <0x03 0x74692c73 0x7761702d 0x78793f00>;
        };

        __symbols__ {
                tft35a_pins = "/fragment@1/__overlay__/tft35a_pins";
                tft35a = "/fragment@2/__overlay__/tft35a@0";
                tft35a_ts = "/fragment@2/__overlay__/tft35a-ts@1";
        };

        __fixups__ {
                spi0 = "/fragment@0:target:0\0/fragment@2:target:0";
                gpio = "/fragment@1:target:0\0/fragment@2/__overlay__/tft35a@0:reset-gpios:0\0/fragment@2/__overlay__/tft35a@0:dc-gpios:0\0/fragment@2/__overlay__/tft35a-ts@1:interrupt-parent:0\0/fragment@2/__overlay__/tft35a-ts@1:pendown-gpio:0";
        };

        __local_fixups__ {
                fixup = "/fragment@2/__overlay__/tft35a@0:pinctrl-0:0\0/__overrides__:speed:0\0/__overrides__:txbuflen:0\0/__overrides__:rotate:0\0/__overrides__:fps:0\0/__overrides__:bgr:0\0/__overrides__:debug:0\0/__overrides__:swapxy:0";
        };
};

[craigerl]

... and finally with the help of AI, we created MHS35.py which is based upon ILI9486.py, and IT WORKS!

MHS35 Display (ILI9486 variant):
https://www.lcdwiki.com/MHS-3.5inch_RPi_Display

MHS35 Python/PIL driver based upon ILI9486.py:
https://github.com/craigerl/MHS35/blob/main/MHS35.py

Thanks guys!
-craig

[SirLefti]

Awesome mate! That's really cool!

I just have to get my head around it.. So we got two very common models: The MPI3501 (my one, currently supported), and the MHS3528 (yours, with your patch). Can you name me your display's manufacturer? My one is from ELEGOO, and basically all shops here at my location will only have that variant for sale. Never saw the MHS one.

If you agree, I'd try to bring both together and maybe bring it also as a package to the PyPi index. But I cannot promise all of this will definitely happen. The issue is that you published your repository with a GLPv2 license, whereas my one - as well as all previous work I utilized - is MIT licensed. I'd like to keep it that way, therefore I need your explicit permission that I can use your changes. I will add this note as well as your name to the authors. Actually, I've seen also the name hemna in your file, is that just an alternative nickname of yours or a co-author of your patch?

I've also seen you went for the RGB565 pixel format. Is RGB666 not working with the MHS3528, or what's the reason for that change?

That's quite a few questions for you, but bringing two of the most common Raspberry displays under one hood sounds promising to me!

[craigerl]

Hi SirLefti,

Yes, I was hoping you might merge these and I can delete my github.

I meant to select an MIT license, so please consider it MIT and you have my full permission to copy/merge. I deleted the gplv2 license for now.

Hemna can be considered a co-author. He/I used Claude to compare your code and examine the device tree overlay to find the differences and come up with the MHS35 ili9486 driver.

Claude suggested RGB565, I suspect it was from the dtoverlay. He (it?) suggested 2-byte words. It was an iterative process with tests that narrowed down these settings.

The exact display I'm using is:

https://www.amazon.com/dp/B0D7VDWBBC

The spec(?) is at

https://www.lcdwiki.com/MHS-3.5inch_RPi_Display

The view angles are NOT as good as the waveshare model, so it's not replacing that any time soon. Colors invert when viewed from the left edge. other angles are good, and dead-on is rather impressive/bright.

Please let me know when/if you merge, I can test.

thanks a bunch for all your support.

-craig

[SirLefti]

Many thanks for your information and input.

I added your init sequency quickly to my dev branch here: https://github.com/SirLefti/Python_ILI9486/blob/99bf603cb65f103dfac8c0ff2bb699fffa25a2fc/ILI9486.py
Can you check if that is working for you?

Notice: The image.py still uses the MPI3501 SKU by default, you have to change that. It is also using rpi-lgpio instead of lgpio as you do in your patch. You have to install rpi-lgpio to use it, it is a compatibility package to replace the old RPi.GPIO while using lgpio under the hood. I plan to support various GPIO back-ends next, to make it more easy to use.

I will also try to add RGB565 mode. I was experimenting a lot today, and I think I got it working as some point with the code you provided, but it broke again for some reason, lol. I cannot make it work for now, at least not with my display.