TheBackShed.com

Forum Index : Microcontroller and PC projects : Are these LCDs Usable?

Author

Message

Rickard5

Guru

Joined: 31/03/2022
Location: United States
Posts: 463

Posted: 04:40pm 13 Oct 2022

Copy link to clipboard

Print this post

I just got handed 11 of These TFT Touch Sheilds from Seed Studios, does anyone have any ideas if I can hack them to a Picomite?

I may be Vulgar, but , while I'm poor, I'm Industrious, Honest, and trustworthy! I Know my Place

matherp
Guru

Joined: 11/12/2012
Location: United Kingdom
Posts: 10310

Posted: 04:48pm 13 Oct 2022

Copy link to clipboard

Print this post

No: they are wired 8-bit parallel which is only supported for the SSD1963. Also, the touch screen does not have a controller so touch is not compatible either
Edited 2022-10-14 02:50 by matherp

Mixtel90

Guru

Joined: 05/10/2019
Location: United Kingdom
Posts: 7937

Posted: 05:18pm 13 Oct 2022

Copy link to clipboard

Print this post

The (PDF) circuit looks like they are SPI, but I've no experience of these.

Mick

Zilog Inside! nascom.info for Nascom & Gemini
Preliminary MMBasic docs & my PCB designs

matherp
Guru

Joined: 11/12/2012
Location: United Kingdom
Posts: 10310

Posted: 05:32pm 13 Oct 2022

Copy link to clipboard

Print this post

Quote The (PDF) circuit looks like they are SPI,

Yes: I'm wrong about the display - sorry, shouldn't make assumptions based on the form factor. So it should work with the standard ILI9341 driver.
The touch is though an issue as the board just exposes the raw resistive x,y dividers

TassyJim

Guru

Joined: 07/08/2011
Location: Australia
Posts: 6283

Posted: 11:14pm 13 Oct 2022

Copy link to clipboard

Print this post

If you really do want to use the touch facility,
I came up with a circuit and code for reading the resistive sensors in MMBasic.
The code was written for the Colour Maximite V1 and is 10 years old. It would need some updating to work with current versions of MMBasic.

A better way would be to add the correct IC so the MMBasic touch commands could be used but my method only requires 2 or 3 resistors.

https://www.thebackshed.com/forum/ViewTopic.php?TID=5291&PID=52791#52791#52791

and

https://www.thebackshed.com/forum/ViewTopic.php?TID=5291&PID=52791#52791#52791

It was an interesting exercise that taught me a lot about touch screens.

Jim

VK7JH
MMedit

Rickard5

Guru

Joined: 31/03/2022
Location: United States
Posts: 463

Posted: 02:02am 14 Oct 2022

Copy link to clipboard

Print this post

Ya Know why the Picomite Thrills me so much ? before I retired I managed a few IT shops, and All the Worker Ants (except my IBM Man) Could Never do what you guys do here. it's like the old days when we still har Real USER GROUPS ,You guys Amaze Me post an Arcane question about Junkbox LCDs, and BOOM answers before Pie come! I love you guys I don't really have a Project for them Yet other than getting the screen part working, the touch part isn't as critical, Like I say they were hand-me -downs and I was deciding if it was worth keeping them

I may be Vulgar, but , while I'm poor, I'm Industrious, Honest, and trustworthy! I Know my Place

Mixtel90

Guru

Joined: 05/10/2019
Location: United Kingdom
Posts: 7937

Posted: 06:41am 14 Oct 2022

Copy link to clipboard

Print this post

Rig one up on its SPI pins, use the ILI9341 driver and see what happens. It looks like you should be able to get the display and probably the SD card working. It'll be interesting to see what happens. :) By changing a link on the display you should be able to get control of the backlight too so that you can switch it off and on or PWM it. The necessary transistor is in place.

Mick

Zilog Inside! nascom.info for Nascom & Gemini
Preliminary MMBasic docs & my PCB designs

stanleyella

Guru

Joined: 25/06/2022
Location: United Kingdom
Posts: 2566

Posted: 05:12pm 14 Oct 2022

Copy link to clipboard

Print this post

It looks compatible but not sure what logic levels it uses from the circuit.

Mixtel90

Guru

Joined: 05/10/2019
Location: United Kingdom
Posts: 7937

Posted: 05:30pm 14 Oct 2022

Copy link to clipboard

Print this post

The display has a 5V input that feeds a 3V3 regulator (U3). The buffers U2 and U4 are being powered at 3V3 so they can accept 3V3. Each input has a 3K3 series resistor so I assume that inputs can also accept 5V. Outputs will be at 3V3, but that's within tolerance for 5V TTL.

A further regulator produces 2V8 for the display logic and backlight.
The base of the backlight transistor has 1K on it and is then linked to 5V to turn it on. Moving the on board link connects it to PD7 instead so it can be connected to a Pico output to control it.

Mick

Zilog Inside! nascom.info for Nascom & Gemini
Preliminary MMBasic docs & my PCB designs

Rickard5

Guru

Joined: 31/03/2022
Location: United States
Posts: 463

Posted: 02:33am 22 Oct 2022

Copy link to clipboard

Print this post

I found this Pin Out of the LCD Does anyone know how I'd wire these pins to the PicoMITE and what option config I'd use on the PM to config it?
Thank you guys

Digital pins

Pin Name Function
D0 NOT USED
D1 NOT USED
D2 NOT USED
D3 NOT USED
D4 TF_CS
D5 TFT_CS
D6 TFT_DC
D7 BACKLIGHT(Selectable)
D8 NOT USED
D9 NOT USED
D10 NOT USED
D11 SPI_MOSI
D12 SPI_MISO
D13 SPI_SCK

Analog Pins
Pin Name Function
A0 TOUCH PANEL
A1 TOUCH PANEL
A2 TOUCH PANEL
A3 TOUCH PANEL
A4 NOT USED
A5 NOT USED

I may be Vulgar, but , while I'm poor, I'm Industrious, Honest, and trustworthy! I Know my Place

phil99

Guru

Joined: 11/02/2018
Location: Australia
Posts: 2640

Posted: 06:32am 22 Oct 2022

Copy link to clipboard

Print this post

Looking at the PDF it isn't clear where to connect Reset, but this might work for the rest. A bit of experimentation may be needed.

OPTION SYSTEM SPI CLKpin, MOSIpin, MISOpin
OPTION LCDPANEL ILI9341, LANDSCAPE, DC, RESET, CS

Using the suggested pins.

OPTION SYSTEM SPI GP18, GP19, GP16

Where
D11 SPI_MOSI = GP19
D12 SPI_MISO = GP16
D13 SPI_SCK = GP18

OPTION LCDPANEL ILI9341, L, GP15, GP14, GP13

Where
D6 TFT_DC = GP15
RESET ? TRST ? = GP14
D5 TFT_CS = GP13
.

Mixtel90

Guru

Joined: 05/10/2019
Location: United Kingdom
Posts: 7937

Posted: 06:58am 22 Oct 2022

Copy link to clipboard

Print this post

First - you can NOT use the PicoMite VGA firmware for this.

The TFT_xxx pins are control pins for the display
The SPI_xxx pins are for the SPI system
The touch panel pins are for.... � (guess) - but we aren't bothered about those.

So it depends on which PicoMite pins you want to use use. You need a set of SPI pins and some to use as control pins.

From the manual....
You need SPI:
OPTION SYSTEM SPI CLKpin, MOSIpin, MISOpin
Try the ILI9341 driver:
OPTION LCDPANEL ILI9341, OR, DC, RESET, CS
OR is orientation - try L to be going on with

Now look at what you have to work with:
SPI_SCK is SPI CLKpin
SPI_MOSI is SPI MOSIpin
SPI_MISO is SPI MISOpin
These can be either of the SPI devices on the PicoMite - your choice.
TFT_DC is the DC pin (can be any pin as long as you specify it)
TFT_CS is the CS pin (can be any pin as long as you specify it)
RESET can be any pin as long as you specify it (It goes to TRST, which shorts out the reset input pin on the driver chip).

The SD card only needs a CS signal as the data pins are connected to SPI. So...
OPTION SDCARD xx
From the schematic, the CS pin on the SD card socket is on TF_CS so xx is the pin that you connect to that.
Edited 2022-10-22 17:00 by Mixtel90

Mick

Zilog Inside! nascom.info for Nascom & Gemini
Preliminary MMBasic docs & my PCB designs

Rickard5

Guru

Joined: 31/03/2022
Location: United States
Posts: 463

Posted: 07:49am 22 Oct 2022

Copy link to clipboard

Print this post

Hey Thanks Guys I'm gonna wire it up first thing in the morning it's almost 3 am here and them Walker boys have been getting me in trouble all night

the trouble with trouble is it always starts out as fun ;)
AGAIN THANK YOU
something Cool will come of this if I get it working :)
Rick

I may be Vulgar, but , while I'm poor, I'm Industrious, Honest, and trustworthy! I Know my Place

Rickard5

Guru

Joined: 31/03/2022
Location: United States
Posts: 463

Posted: 01:42pm 22 Oct 2022

Copy link to clipboard

Print this post

sorry Guys tried it 3 times and no Joy

I may be Vulgar, but , while I'm poor, I'm Industrious, Honest, and trustworthy! I Know my Place

Mixtel90

Guru

Joined: 05/10/2019
Location: United Kingdom
Posts: 7937

Posted: 02:48pm 22 Oct 2022

Copy link to clipboard

Print this post

What are you connecting where and with what options set?
Also, if you are messing about with changing options, you must use OPTION LCDPANEL DISABLE before you can set up new options.

Concentrate on just the display first. You'll need to set up the SYSTEM SPI and LCDPANEL options. The SPI pins must be on a valid hardware SPI port of the PicoMite. Once they are set you shouldn't need to mess with them again.

Mick

Zilog Inside! nascom.info for Nascom & Gemini
Preliminary MMBasic docs & my PCB designs

phil99

Guru

Joined: 11/02/2018
Location: Australia
Posts: 2640

Posted: 09:47pm 22 Oct 2022

Copy link to clipboard

Print this post

Adding to the above, is the backlight enabled?
Maybe it is working but invisible.

TassyJim

Guru

Joined: 07/08/2011
Location: Australia
Posts: 6283

Posted: 12:15am 23 Oct 2022

Copy link to clipboard

Print this post

Forget the Arduino pin numbers, they only confuse.

Compare the schematic to the PCB layout and you will see which pins to use, including the RESET which you were missing.

Jim

VK7JH
MMedit

Print this page

To reply to this topic, you need to log in.