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Forum Index : Microcontroller and PC projects : Two problems - #1 ILI9341 not working and #2 I2C not working
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Mixtel90 Guru  Joined: 05/10/2019 Location: United KingdomPosts: 6798 |
I keep saying this, but we all do it... :) Breadboards are not designed to take male header pins, they are too big for the contact springs. Cheap breadboards in particular don't have great springs to start with so we can't really expect them to have a long life when we abuse them. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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phil99 Guru Joined: 11/02/2018 Location: AustraliaPosts: 2140 |
The reason for the wrong orientation will be due to the ILI9488 driver being for a 480w x 320h pixel panel but yours appears to be 320w x 240h so 320 becomes the height and 240 the width . The other half of the pixels are located off the right hand edge. If that is the only driver that works a work-around for the colour problem is to redefine the colours with constants. eg if RGB(red) is blue then:- CONST Blue = RGB(red) Because of the intermittent hardware you can't be sure if any of the drivers you have already tried are actually wrong. Retry them when the hardware is reliable. |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6798 |
The best way to connect to these is probably by using female Dupont connectors. They may not be perfect but at least you can feel if one isn't gripping the pin properly. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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stanleyella Guru Joined: 25/06/2022 Location: United KingdomPosts: 2129 |
It's a good fit on new bread board if you just plug the display into the board. Dupont connector are a good option if you use the ribbon cable type.. neater, one end to display, other end to picomite. Backlight needing resistor would be a problem with no bread board though. |
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| VK2AHB Regular Member  Joined: 28/07/2022 Location: AustraliaPosts: 51 |
To recap: The I2C problem seems to have been due to a connection problem which was fixed by swapping out the Pico board. The ILI9341 problem was partially solved by using ILI9488, although with wrong dimensions and colours. While that was working, I plugged in the RTC and DS18B20 on the board and jumoered the Vcc, GND, SDA and SCK lines. The program was running OK, printing to the terminal window but nothing on the display. I moved the Pico and display to another breadboard with external 5V supply rail. Still nothing. Last year when I was here, I finally got the ST7735 display working fine then it suddenly stopped. I am wondering if this is related to 3.3 vs 5V supply. |
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| Mixtel90 Guru Joined: 05/10/2019 Location: United KingdomPosts: 6798 |
I'm pretty sure that the TFT display problem is one of two things: 1: It isn't either a ILI9341 or a ILI9488 on them. 2: You still have a hardware connection problem. You can't do much about the first apart from keep trying other drivers. You have to rule out the second before you tackle the first. At the very least that will involve a continuity test (with the power off) between the soldered pin connections (not the breadboard) on the Pico and the display. The I2C problem could also be related to 2. There simply isn't anything else to go wrong on I2C if the addresses are right. Two wires and two resistors, that's all. It would make me want to start again with a different breadboard. It's quite possible that the area where the Pico is plugged in has already failed in several places. Note that the terminal will still work ok even if the GP pins have no connections! ===================== On a test rig it's not a good idea to power the Pico and it's display from separate supplies. Once things are stable it's something you can look at, but not on a test rig. The reason is that data lines are also resistive (you hope!) power supply lines while one item or the other has no power. That can screw up all sorts of things and even cause damage. Just don't do it. My basic setup is to power the Pico from USB and take 5V from VBUS to feed the display. That keeps it nice and simple and you can't mess things up. All the 3V3 stuff then comes from the switcher on the Pico. If I want low noise stuff I rarely attempt it on a breadboard as it's usually pointless. There is also the risk of accidentally pulling out the 3V3EN link. If there's not enough current from your computer USB to power the Pico and ILI9341 then use a powered USB hub. Displays are usually better on Dupont leads than plugged into a breadboard. They are cheaper than replacing a breadboard and can even have new connectors fitted should they lose their grip or break off. They also take up a lot less space on the breadboard. An alternative is to keep a display plugged into a breadboard and patch wires across to the main one when needed, but I find that clunky. For more serious playing I use one of my PicoMite Backpack boards, which has the display, RTC and SD card already connected. Mick Zilog Inside! nascom.info for Nascom & Gemini Preliminary MMBasic docs & my PCB designs |
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| stanleyella Guru Joined: 25/06/2022 Location: United KingdomPosts: 2129 |
quote "The program was running OK, printing to the terminal window but nothing on the display." Display uses text x,y, not print I think |
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