#lt6502 — Public Fediverse posts

@ghalfacree Nice, but can it do wizzy graphics? like my 6502 Laptop?
https://www.maddox.pro/wp-content/uploads/2026/02/Assembled_LHS_Open-1024x963.jpeg

and

https://files.mastodon.social/media_attachments/files/116/065/459/269/002/826/original/ce1706561cbed4e8.mp4

ok, I'll admit, I like that BOOK II laptop, I'm kinda tempted...

#LT6502

Codeberg, any good?
I'm thinking of moving my #LT6502 & #LT6502b projects there as I'm tired of AI rubbish.
Anyone else use them? thoughts?

Second version of #LT6502 underway, so fa so good. Powers up, all voltages are correct.
So onto soldering in cpu and bring up.
#LT6502b #retrocomputing

Almost done with the case for the next revision of my #LT6502
I have the hinges to sort yet, but I’m very happy with the size of this.
This is about 31mm thick, just under half the previous version and has a bigger screen (10.1”)

Working on a new version of #LT6502, currently has the imaginative title of "LT6502b", this is much thinner... currently it is 16mm thick, which is just under half the thickness of the first version base.
It probably wont have an expansion slot as there is not much space inside.
I've looked at a lot of laptops and have learned from my first version.
I'm also going with single 18650s on the rear in some kind of curved extension to the base (TBD).

Well, my version of the “event horizon” code for the BBC micro looks nothing like the page I found it, but it does looks cool.
#LT6502

Trying to decide if I should make a second version of the #LT6502 , try and make it slimmer and maybe a bigger screen?
My limitation in size is always going to be the battery pack though :(
Anyone have any good suggestions for solving that problem? It needs to be a 10,000mAh battery pack or more.

Converted a BBC basic program to run on my #LT6502 computer

More shots with the lid “closer”, not perfect but for a first go I’m ok with it.

#LT6502 #retrocomputing

My #LT6502 is assembled.
The hinges work really well, if a tad fiddly to get right.
The case, well there are a few gaps here and there, this could be improved with more clips.
Also I’ve learned a lot about 3D printing and there is a lot I would change.
But overall, I’m happy with it.
It’s a bit of a chonker but that honestly doesn’t bother me.
#retrocomputing

Final commands added to EhBASIC;
LINE,
SQUARE,
ELIPSE and
TRIANGLE

PLOT and CIRCLE were added a few days ago.

These all use the displays on board acceleration so are very snappy.

Hinges next, then a bug in the keybed, couple of resistor changes for LEDs and it’ll be done.
Well until I start on the expansion card ;)

#LT6502 #retrocomputing

Hmmm so printing on a raft solved one problem but the finish isn’t great.
I need to do some more work on trying to clean it up (display bezel).
The hinge is coming along but it’s taking quite a bit of work to get it just right. You can see a couple of the bits on the LHS between screen and base.
I am very pleased with the CF load/save/dir functionality :)
#LT6502 #retrocomputing

SAVE, LOAD and DIR now working on my #LT6502, though they are NOT FAT compatible. Which is fine with me :)

Progress is being made on the case for my #LT6502 project.
I’m quite proud of it so far, the top needs a few tweaks.
Then I need to design the case for the screen.

Tweaked the colours and made it wider so it’s the width of the screen.
I’m really enjoying this, I feel like it’s time to get back into my James Gleick Chaos book and do some experiments.
But I need to sort CF storage and a few more basic commands.
#retrocomputing #LT6502

I did a quick version of the “bubble verse” program on #LT6502 and after a while it’s looking incredible.
I’m going to leave it running for an hour two.
I do want to tweak the code to show what iteration it’s currently on rather than the start iteration.
#retrocomputing

#LT6502 now has scrolling on the screen, it might not sound like much but it took a lot of work to get right.
#retrocomputing

I’ve heard about these bulletin boards tha are resurfacing, how would I go about getting online with one or two? I’m thinking about some kind of interface for my #LT6502 project.

#LT6502 getting there now.
We now have the LCD working for EhBASIC, I chose an orange/amber colour for the text as I find it easier on my eyes.
This is running from battery.
It has a power on beep, currently I’m pasting code via the serial console.
After I’ve sorted scrolling of the text I’ll be working on loading/saving using the compact flash card.
#retrocomputing

I got the 9” 800x480 display working on my #LT6502 project. Played with colours and here is a full resolution Mandelbrot.
I’m not convinced about the viewing angle on this panel so I may have a go with the other panel again.
This took about 3 hours.

I managed to get a BASIC program to read a sector of the CF card on #LT6502 and show it on the display.
New display is due today so I’ll be working on that.
And add those bits to my bios.

Tweaked the #LT6502 case to make it work with some connectors and add a bit more in the way of clips/fixing for the base lid.

My #LT6502 running from battery and generating a Mandelbrot at 800x480, I’m just waiting for the 9” screen and then I can work on the case and the firmware to initialise the screen.

So relented and I have ordered an RA8875 based display for my #LT6502.
It’s 9” so not quite what I wanted but give the RA8875 works on both my tower PC6502 and my #LT6502 board where the 7673 based display doesn’t, it seems to be a no brainer really. It’ll be 800x480 at 9” so text should be readable without a microscope which was a worry I had with the 10” 1024x600.
I’ve got a 5” version of this display somewhere so I should be able to get test code going before the 9” arrives.

#Lt6502 display update: so it seems that driver code I found from the supplier may be incorrect <Doh!>
So I’ll try something tonight to see if I can read a register which is based on the datasheet, or at least my understanding of the datasheet.

Really struggling to make any sense of the LT7683 data sheet (https://www.buydisplay.com/download/ic/LT7683.pdf) for the display I've chosen for #LT6502 (https://www.buydisplay.com/download/manual/ER-TFT101B4-1-5553_Datasheet.pdf)
I can't even seen to read or write despite it claiming to have the same 6800 style 8bit interface as the RA8875 (which I've used and proven is good).
First problem is, I can't understand of RS = 0 is data or register (anyone know?) I've tried both combinations, I'd LIKE to be able to read any register, but I never get back a consistent value.

Been working on #LT6502 and it now has Reduced LED brightness, a beeper and compact flash is working.
Next the big challenge, the display.

Feeling brave I connected the battery to my 6502 laptop board.
It works.
I can power it from battery and I can charge it.

One thing I’m puzzled about is the charge LED, with power in+battery connected but no load the charge LED flashes. With a load the charge LED is on. Anyone else used the MP2636 charge IC?

I’ve not measured voltages yet and I haven’t left it charging for more than a few minutes ye either.

One thing, I need to sort the LED brightness, oops.

#LT6502

Wohoo! Keyboard input is now working for my #LT6502, so I can type programs and commands into EhBASIC and they work.
However this does highlight a problem with keyboard code, so I need to figure out how to compile C code for #AVR (ATMEGA644P) in ubuntu (windoze has blocked my ATMEL-ICE and I can't be bothered to fight windoze).
Any pointers on how to compile?

Wohoo! Keyboard input is now working for my #LT6502, so I can type programs and commands into EhBASIC and they work.
However this does highlight a problem with keyboard code, so I need to figure out how to compile C code for #AVR (ATMEGA644P) in ubuntu (windoze has blocked my ATMEL-ICE and I can't be bothered to fight windoze).
Any pointers on how to compile?

Work on the keyboard link to the main #LT6502 board is going well.
Basic test works, sending and receiving.
I’ve begun integrating it into the firmware, so on boot it shows C/W/M on the keyboard for cold, warm or monitor.
Next up is adding receiving data from the ACIA so the laptop can be fully self contained and not need a console.
#retrocomputing

Sorted the problem with the #LT6502 and console, not sure why but I swapped the TXE and TXF pins on the CPLD and it worked.
Now running basic with almost 48K of RAM.
Using #PicoROM to get the firmware working.
Need to add other bits now (VIA, 6521 and compact flash).

Interesting problem with #LT6502 main board, I've got the RAM, ROM, CPU and Glue on now.
I've the minimal glue logic in and I can see it starts EhBASIC and I can even run Mandelbrot.However, it only sends data out when data is coming in. I.e. to see the Mandelbrot being generated I have to hold down a key.....
Glue code is the same as my #PC6502, schematic for the FT245 is the same, so I'm very confused.