Trying to get Landzo 3.5" Display Touch-feature working


The are only shipping to US. When I call the link, it says, they don’t ship to germany.


Geez, that is really lame :rage:

Starting my zynthian build: alternative LCD, DAC, encoders

I used Waveshare’s image of Raspian with the Waveshare3.5A driver pre-installed and it worked with the two rows switched with my extra wiring with the official ribbon cable. Just to test, once I shut down, disconnected the All-In-One board, but left the screen connected, then Touch worked immediately. The screen refreshes very slowly, I’m not sure if that’s normal. I haven’t tried with Stretch installing the drivers at Waveshare afterwards.

Looking at the wiring here Failed starting software [solved]

Would I need to use my own custom wiring between the middle ribbon cable connector and the AllInOne board?

I’d like to make a graphic so folks understand what I mean by the official ribbon cable transposing the pins. It is as if the OzzMaker screen is expecting an orientation of looking UP through the RaspberryPi and the “normal?” HAT displays are expecting an orientation of looking DOWN onto the RaspberryPi pins. This is one way I can explain how the rows are transposed without making a graphic. If you rotated the 40-pin connectors 180 degrees pointing up, held it next to the 26-pin connector also pointing up, you would have the two rows transposed. I imagine the HAT connector on the OzzMaker works just like the Waveshare35A, but the ribbon cable is meant to connect to male pins on it’s short side, correct?

From reading the Waveshare32 thread and the newer wiring diagram I’m not understanding which pins I should rewire so they are not conflicting with the Waveshare35A’s touch feature. Should I visually layer the pins AudioInjector, the AllInOne, and the Waveshare35A need and see where there are overlaps and open GPIOs?

The Touch feature isn’t a big deal for me now, but maybe with any more complex interfaces added to Zynthian? I understand if this is something I’ll just have to figure out myself. But I did want everyone to understand why I am switching the two 13-pin rows on the 26-pin when I am connecting to the Waveshare35A. I’ve checked with a multimeter where the 3.3V and the 5V and grounds are. Using the ribbon cable with the Waveshare35A is not the same as plugging the display directly to the RPi pin or the AudioInjector. The 26-pin ribbon connector is, in effect, upside down or mirrored might be a better word. I can try to make a graphic if this isn’t making sense.

Edit: I did get the waveshare driver to work in Stretch as well. Wooo. :confused:


As I said before, I would try the waveshare32 wiring. And that’s more than turning it.

Montag, 11 Juni 2018, 02:12vorm. +02:00 von rockwater



1.) I wasn’t meaning the turning was related to Waveshare32 solution, or the solution to getting Waveshare35A Touch working. The turning I was referring to is that the 40-pin connector, facing down onto the RPi, expects 3.3V on the left (Pin 1) and 5V on the right (Pin 2). The Waveshare35A also expects this as it is a Hat.

The official ribbon cable for the kit V2 26-pin connector has 5V on the LEFT (where the Waveshare35A expects 3.3V, Pin 1, etc) and 3.3V on the RIGHT (also is not Male of course). Maybe would help others later if they happened to try this v2 cable with a Waveshare or other Hat display. Someone tell me if I’m crazy? :slight_smile:


2.) I know you have recommended this before, but I don’t understand how I can apply the Waveshare32 wiring while using the newer Kit v2 All-In-One board.

Are you referring to this:

And also choosing PROTOTYPE-4-WS32 in the webconf? I couldn’t find what you meant by a line I should remove you mentioned earlier.

Can I accomplish this while using the Kit v2 All-In-One board?

Do I need to make a new ribbon cable with a 40-pin Male connector / custom wiring?


Would I need to re-organize the connections between the AudioInjector 40-pin and the All-In-One 40-pin?


Perhaps using the AudioInjector instead of the HiFiBerry is making this overly complicated as well?

If this is too much, and something I just need to figure out on my own, I understand. Maybe I should work on my own pin map also?


If this could help someone else later, maybe it would be worth it. But of course now I wish I had bought an already supported display - I’m learning! Maybe there are some simple basics about how Zynthian works that I don’t understand yet (such as how to arrive at the values for the zyncoder_pin lines, guessing it’s all in the wiki.)

Anyways, I don’t know if I’m actually contributing or just clogging up the forum, sorry! I’ve spent over two hours on this post and a lot more trying to get this display to work normally, maybe just not worth the time now. :confused: :zipper_mouth_face:


Yep, I would have used custom wiring.

You don’t need a complete new ribbon cable. But unfortunately a lot of single cables. And a connector.

Dienstag, 12 Juni 2018, 05:14vorm. +02:00 von rockwater


just follow the picture you posted above. I did the pin-work keeze prepared already. Just use the Ws32 wiring in webconf once you exchanged the wiring physically.


I think the solution for the 2-in-1 board is not the same as the All-In-One board. I found the conflict pin in the 2-in-1 board, but that is not what I’m using.

I was looking at the old schematic for the 2-in-1 board.

When I look at the schematic using MCP23017, All-In-One, I cannot find any conflicts between the All-In-One board, the AudioInjector hat, and the Waveshare35A hat display. This would seem to indicate this isn’t a hardware wiring issue?

Also, if I remove the ribbon cable, and connect the Waveshare35A directly on the AudioInjector, Zynthian UI will only load on the display if I have a mouse connected. If I have wiring set to Dummies, wouldn’t the Touch be working on the display without the All-In-One board? I can navigate fine with the mouse. (Also could do this with everything connected, just no working Touch).

Between these three pinouts/diagrams I can’t find any pins used by all 3 devices (except for shared I2C, power, and ground.)

This would mean this is a software issue, correct? At least, not one that can be solved by re-wiring and re-assigning encoder/switch pins. This is not the same situation as the previous Kees/Waveshare32 solution, right?


from this:


Hi @rockwater!

The All-In-One circuit main improvement was avoiding this kind of conflicts by using only 2 GPIO pins from the RBPi for the MCP23017 interrupts (INTA & INTB). For that i’m using pins 36 & 37 that are rarely used by other devices like displays and soundcards. So … as you correctly set, AudioInjector and Waveshare shouldn’t have conflicts with All-In-One.

Anyway, my experience with AudioInjector Stereo boards is that they make strange things. Although i’m not completely sure, i suspect that the double side 40-pin connector is not a very reliable part and some pins fail randomly from one unit to other. Quite strange …



Thank you - well darn, not sure if it’s worth getting another AudioInjector Stereo?, possibly the Zero, I think Zero I would need a male and female 40-pin soldered on though to use as a hat? I don’t have an immediate need for Audio-In but I imagine maybe in the future. I do have a tiny PCM5102A DAC that I had working before, but not with the Landzo display - I think that would need some special split wiring or ribbon as well to pass thru the pins as it’s not a hat. Wonder if HiFi-Berry has audio-in in their future…


Nice analysis. I am using zero and don’t have issues. Going to use the second one soon.
But wait for the ultra and subscribe on Kickstarter.


Yeah it does look pretty decent! I’ll have to look at it again, it looked really big!


For the Zero, I would need this, right?


I used this


We would need the female header on the bottom to stack onto an RPi 3 though, wouldn’t we?


No real stacking:


Cooool, I really need to try making ribbon cables :grin: