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dddns
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Joined: 20/09/2024
Location: Germany
Posts: 534

Posted: 12:57pm 13 Jul 2025

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phil99 said
If all else fails try ILI9481, ILI9341, ST7789_320 etc.

It might be a newer IPS panel, so I would try ILI9488W in first instance

@Bryan: A picture of the display could help
Edited 2025-07-13 22:59 by dddns

Bryan1

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Joined: 22/02/2006
Location: Australia
Posts: 1460

Posted: 11:18pm 13 Jul 2025

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Morning Guy's well over a caffine decided to try a few options so I tried different drivers and to my surprise the backlight worked with EVERY driver but the gui test lcdpanel failed on every one

Here is a pic of the back of the lcd

So my next job with this is to rip out all the wiring and start again just to see if that is the problem.

phil99

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Joined: 11/02/2018
Location: Australia
Posts: 2626

Posted: 12:14am 14 Jul 2025

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Ok that looks like a standard ILI9488 and has U1 fitted so Vcc should be 5V.

If you can wire it up like this, which I have working, hopefully there will be a different outcome.

Only System SPI & LCDPANEL drivers installed (no touch or SD)
Panel Pico
VCC VSYS (5V)
GND GND
CS GP13
RESET GP14
DC/RS GP15
SDI(MOSI) GP19
SCK GP18
LED GP7

In your first test the SD card also didn't work suggesting the SPI wiring may be the culprit, provided the SD card was no more than 32GB as that is all the LittleFS in the Pico can handle.

If the panel still doesn't work the SPI bus can be checked with just the SD card.

Remove the LCDPANEL and driver and add the SDCARD driver

manual p36 said System SPI Port
This is a port that will be used for system use (SD card, LCD display and the touch controller on an LCD panel).
There are a number of ports and pins that can be used (see the chapter PicoMite Hardware) but this example uses SPI on pins GP18, GP19 and GP16 for Clock, MOSI and MISO respectively.
OPTION SYSTEM SPI GP18, GP19, GP16
Then MMBasic must be told that there is an SD card attached and what pin is used for the Chip Select (CS) signal:
OPTION SDCARD GP22

Edited 2025-07-14 10:22 by phil99

Bryan1

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Joined: 22/02/2006
Location: Australia
Posts: 1460

Posted: 02:58am 14 Jul 2025

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Well rewired it all up did a clear flash and put 6.03 back on and just did the lcdpanel option and noticed it didn't light up like before so did a gui test lcdpanel and got the bubbles

Went and did the gui calibrate and got thru it first time.

PicoMite MMBasic RP2040 Edition V6.00.03
OPTION SYSTEM SPI GP18,GP19,GP16
OPTION COLOURCODE ON
OPTION CPUSPEED (KHz) 200000
OPTION LCDPANEL ILI9488, RLANDSCAPE,GP15,GP14,GP13,GP7
OPTION TOUCH GP12,GP11
GUI CALIBRATE 0, 240, 204, 1251, 858
OPTION SDCARD GP22

So got the lcd and touch working and I replaced the 32gig sdcard with a 2 gig but still no sign of the sdcard working

So a bit more sleuthing to to work this sdcard one out.

phil99

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Joined: 11/02/2018
Location: Australia
Posts: 2626

Posted: 03:08am 14 Jul 2025

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Good to hear the LCD is working!
The SD card is drive B:

Type B:<enter> at the prompt to change drives then "files"

A 32GB card should be ok but that is the maximum.
Edited 2025-07-14 13:12 by phil99

Bryan1

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Joined: 22/02/2006
Location: Australia
Posts: 1460

Posted: 03:16am 14 Jul 2025

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[CODE> B:
> files
B:/
<DIR> dtxhelp
11:48 18-02-2012 589 dates.txt
16:10 05-07-2013 108160 DTXHELP.TXT
10:11 19-08-2018 2039 EDITOR.TXT
10:11 19-08-2018 799 FUN1WIRE.BAS
10:11 19-08-2018 4798 ONEWIRE.BAS
18:13 18-08-2018 23970870 ruff.bmp
00:00 01-01-2000 640 TEMP.BAS
1 directory, 7 files
>]

Thanks Phil

now time for lunch then spend some time reading the manual to get the gui setup

As one can see from the dates this is how long I have been away from this
Edited 2025-07-14 13:17 by Bryan1

Bryan1

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Joined: 22/02/2006
Location: Australia
Posts: 1460

Posted: 08:53am 14 Jul 2025

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Well just read right thru the Advanced Graphics PDF and at no point did I see any reference to in/out pins so are any examples around where it does show as it would be great in me learning.

Now with this 2040 and the LCD my goal is to use for reading the cnc input/output like the limit switch's and temp probes I'm going to in each heatsink of the DM556's so I can check if they are going to heat up too much. Also it would be good on gui page 2 to have a toggle setup for jogging each axis.

I do need to get on and purchase a heap of stuff for the big pico so for now I'm going to sort out the 2040 where I can. Just got a bit more wiring to do on the cnc then I use the 2040 to run that test code so I can get each step calibrated.

phil99

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Location: Australia
Posts: 2626

Posted: 12:34pm 14 Jul 2025

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What you want is in the main manual p45 "Using the I/O pins"
As you have found the Advanced Graphics PDF covers displaying the data after you have got it, and user input via the touch screen.

I usually start just using the console for showing data and user input.
After getting and processing the data is all bug free it is time to add all the graphics etc.

The main manual also has a chapter on Graphics Functions.
Edited 2025-07-14 22:40 by phil99

Bryan1

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Joined: 22/02/2006
Location: Australia
Posts: 1460

Posted: 05:09am 16 Jul 2025

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As I only have a small breadboard decided to do a bit of shopping on fleabay and got a big breadboard, 10 off 40 pin male single pin headers, 10 off female headers and found 20 off sharp PC817 opto's for $3.

So this will get me going with the big pico and once I have everything working a pcb can be designed.

Now with the PC817 what sized resistor is used on the input side? Looking at the datasheet didn't give any clues but this ol' grey mattered brain hasn't looked at a datasheet in years

PhenixRising
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Joined: 07/11/2023
Location: United Kingdom
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Posted: 06:32am 16 Jul 2025

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In my case, which is 24VDC, I currently have 2K2, 500mW (to be safe) spec'd but I might increase that resistance. These are only input signals from machine sensors.

Bryan1

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Joined: 22/02/2006
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Posts: 1460

Posted: 06:46am 16 Jul 2025

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I will be using the opto's for the step, direction and enable signals now as the pico only outputs 3V3 I will be using 5V on the opto output so suit the minimum spec's of the DM556.

Still got a couple of weeks for everything to arrive so gotta get my thinking cap on so everything falls into place. I do need to make list of all the passives I will need and I'll do a trip down the hill to get all the parts.

Mixtel90

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Posts: 7891

Posted: 07:04am 16 Jul 2025

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Depends on what voltage you want to use for the inputs. Opto-couplers are current driven, not voltage. I'd allow a couple of mA.

As an example I'll work it out for 12V input.

The forward voltage Vf is a maximum of 1.4V for the PC817 so, the voltage across the resistor will be 12 - 1.4 = 10.6V
I'll allow 3mA for the forward current.
The resistor will have a value of 10.6 / 0.003 = 3533Ω
The closest standard value to this is 3.3K.
Working back, this will give a current of 10.6 / 3300 = 0.0032A (3.2mA)

The resistor will dissipate some heat. We can calculate this using P=I*I*R:
P = 0.0032 * .0032 * 3300 = 0.034W which is no problem at all.

As this is operating the PC817 towards the bottom end of its current range you can use the same resistor value up to about 32V DC input:
Voltage drop = 32-1.4=30.6V
Current = 30.6/3300=9.2mA
Dissipated power = .0092*.0092*3300=0.279W
So you'd get away with a 0.5W resistor

If you drop the input voltage to 6V using the same resistor the current will halve to about 1.5mA (not accurate as Vf changes at low current). This might just be possible as the collector current that you are after is only low when you want inputs.

Opto couplers have what's called a Current Transfer Ratio, which is the ratio of the collector current to the diode current - rather like the current gain. The minimum for this opto coupler is 50 at 5mA. The range of transfer ratio is shown on the device by a letter code. I'm guessing that these will be the minimum of 80-160%. So, as the maximum allowable collector current is 50mA for this device 1mA through the diode should be fine.

Mick

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

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