ELLO 16P

Description

When I started the design of this one last year, my only goal was to make the cleanest possible little SBC without aiming for massive parameters or speed.
However, I also wanted to make it flexible enough to be actually useful.

The parameters are:
PIC24FJ256DA210 working at 32MHz off the internal generator; additional crystal for the real-time clock.
4 Mbytes external SRAM connected to the memory bus of the PIC.
Video output to a standard monitor in 64 colours, plus a small speaker.
SD card connector.
RS-485 line driver.
UEXT20: 20-pin extended version of the UEXT interface, compatible with all the existing on the market UEXT modules.
PS/2 keyboard and PS/2 serial interface connectors.
Additional serial memory module expansion receptacle.
Power hold-up circuit.

This is the only known to me computer built around the PIC24 core. Because this PIC has a built-in graphics controller, the entire system is only 6 ICs.

Details

The situation with the software is this:

There isn't much of it yet. I have verified the proper functionality of the entire hardware, seen a nice video output of a demo picture on the display, and that's pretty much all of it so far. I was originally planning to write a small Basic interpreter, or maybe port my own FANF shell (https://github.com/knivd/FANF), but then got carried away with other ideas and eventually forgot. Only today the board appeared again before my eyes, and reminded me about some unfinished business... ;-)

Anyway, the ELLO 16P bare boards are really cheap, and I have a few of them already made. Currently looking for place where I can stick them online, so everyone can get one for themselves.

Files

PCB.pdf

3D rendering of the assembled PCB

Adobe Portable Document Format - 2.66 MB - 06/24/2019 at 13:55

Preview

manufacturing files for ELLO 16P.zip

Gerbers

x-zip-compressed - 5.59 MB - 06/24/2019 at 13:54

Download

Schematic.pdf

Schematic

Adobe Portable Document Format - 188.69 kB - 02/21/2016 at 18:50

Preview

Assembly Drawings.pdf

What goes where

Adobe Portable Document Format - 55.75 kB - 02/20/2016 at 22:08

Preview

BOM.xls

Bill of materials

ms-excel - 16.50 kB - 02/20/2016 at 22:07

Download

Project Logs

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Now available on Tindie!
Kn/vD • 03/31/2021 at 08:21 • 0 comments

ELLO 16P PCBs are now available on Tindie
Back from retirement
Kn/vD • 06/24/2019 at 15:21 • 0 comments

This project was enjoying retirement for a while, but due to interest I have decided to bring it back. Currently asking Tindie how to bring it back in my store too. Ordering a new batch of freshly-made PCBs from the last revision.
4 years later it is still the only serious PIC24-based computer that I know of, so that makes is a pretty good toy for "21st century retro computing" :-)
Now available to build it yourself (if you want)
Kn/vD • 03/22/2016 at 13:21 • 0 comments

The link: https://www.tindie.com/products/KnivD/ello-16p-bare-pcb-for-diy/
Enjoy!
Four boards
Kn/vD • 03/01/2016 at 14:06 • 0 comments

Just checked in my drawer, and I pulled four nearly fully assembled ELLO 16P boards with only missing SW1 and J2. These are the pre-release revision samples and fully operational (well, except for one small bug with the LED which is fixable with an extra resistor).
My storage space if pretty limited, and I am willing to give these boards away to enthusiasts who might like tinkering with them to get some software running and expand the community. I don't want any money for these except for my postal expenses.
Anyone keen to get one of these, please drop me a line at knivd@me.com
Will be available soon from Tindie.com
Kn/vD • 02/24/2016 at 11:15 • 0 comments

I am working to get a small batch of new ELLO 16P boards made, and release them at http://tindie.com within the next couple of weeks
Had the wrong schematic file...
Kn/vD • 02/21/2016 at 18:53 • 0 comments

Just replaced the schematic file with the latest revision. The old one was still carrying remnants of the mistakes from the first revision of the board. This one is the final R2 file.

View all 6 project logs

Discussions

harrythespider69 wrote 06/23/2024 at 22:54

I just found a pre-built Ello 16p in my mess of a home office/study. In its original packing/shipping carton, wth the post mark of 12 Aug 2019!

I don't think I ever used it, or even powered it on.

Where can I find basic details to get this thing running? I'd like to port my Tiny Pascal compiler over to it - PIC24 was the first processor it ever generated native code for, about 10 years ago, and pretty efficient it was too!

Are you sure? yes | no

Hacker404 wrote 03/01/2016 at 10:14

Can i buy the board?

Looks great, love to give it a try.

Are you sure? yes | no

Kn/vD wrote 03/01/2016 at 10:18

A small batch is being manufactured at the moment, and I will post a an update as soon as the boards are ready. Maybe about two weeks from now.

Are you sure? yes | no

Freire wrote 02/23/2016 at 00:09

MMBasic is a free and open BASIC interpreter for 32 bit microcontrollers.

http://mmbasic.com/

Are you sure? yes | no

Matthias wrote 02/22/2016 at 20:57

I would throw in http://retrobsd.org/wiki/doku.php but than i realized it only runs on PIC32.

Are you sure? yes | no

Kn/vD wrote 02/22/2016 at 21:13

This one won't do it because it carries a different concept behind it, but my ELLO 2M laptop does have a chance... https://hackaday.io/project/9692

Are you sure? yes | no

danjovic wrote 02/21/2016 at 11:49

Amazing build, pal! Can it run software from external memory too? Is the video handled entirely by the display controller builtin or does it need service from CPU?

Are you sure? yes | no

Kn/vD wrote 02/21/2016 at 11:59

Thanks! The video is entirely handled by the internal hardware. Running software from the external memory obviously will needs some input from pic because the external memory is originally thought by Microchip to be data memory only, but that is no big bother since I was planning to have it running a HAL machine anyway.

Are you sure? yes | no

Oscarv wrote 02/21/2016 at 11:31

Very very cute indeed! To get some software base going, why not implement a CP/M emulator on it? There's a couple of plain-C implementations that already run on other microcontrollers. https://hackaday.io/project/3709-cpmduino . Should be relatively easy to port and gets you a whole library of software.

Are you sure? yes | no

Kn/vD wrote 02/21/2016 at 11:56

Thanks! I will have a look

Are you sure? yes | no

ELLO 16P

Description

Details