Atom 2k18 ?

[roland]

I don't think you can program the device over USB.

I assume that the USB is needed for powering the board during programming. The programming goes via the JTAG connector. IMHO.....

Actually, a nice fix might be to drive the two Vin pins on the header via a schottky diode. Then no reverse powering would be possible. Vin is just used to drive the 3.3V regulators, so feeding in 4.5V should be fine. There are already schottky diodes (MBR0530 = 0.5A) on the other power feeds.

So that's two extra diodes on the Atom board. That's a nice fix because there's no need to modify the FPGA board.... It's getting very interesting this board

[hoglet]

So that's two extra diodes on the Atom board.

Or even just one diode, driving both the vin pins (connected together).

Dave

[Elminster]

Could you build some sort of upurs solution around the usb? I am guessing you might be able to drive it faster than the 115k on the user port of beebs.

We can already upload and download at 115K (with CRC).

It doesn't need to use UPURS-style bit-banging, as the GODIL in the New Atom has a proper serial port that runs this fast.

It might even go faster, but then the CRC (and the fact the Atom can be 1MHz) become the bottleneck

The software support for that is in the FPGAUtils ROM:

Code: Select all

FPGAHELP - Shows the version and commands in the ROM.
BAUD <Baud Rate>, Sets the UART Baud Rate (default is 115,200).
UPLOAD <Start>,<End> - Uploads from Atom memory to the UART.
DNLOAD <Start> - Downloads from the UART to Atom memory.
CRC <Start>,<End> - Calculates an Atom CRC over Atom memory.
BEEB - Switches to BBC Mode.
FLASH <Start>,<Bank> - Programs a 4K bank of the FLASH from Atom Memory.

I do miss my Atom.... been doing far to much Pi stuff recently

Dave

That doesn’t look like all the facilities of the upurs ROM though?

I have nothing to try, I am waiting for the 2k18

[hoglet]

That doesn’t look like all the facilities of the upurs ROM though?

I guess it's not really trying to offer everything that UPURS does. Like most things on the Atom, compared to the Beeb, it's a bit more primitive. As a comparison, Atom Utility ROMs are only 4K, compared to 16K in the Beeb.

All that was needed at the time was to shift data between the Atom and my Linux box, as fast as was practical, with some assurance that it wasn't getting corrupted. *UPLOAD and *DNLOAD do just that.

No one has since asked for anything else....

...but that's probably because I'm the only person that has ever used this!

Dave

[Elminster]

Atom, and therefore a possible clones run, seem to be getting popular recently, so that could keep you go in new stuff todo after RGB hdmi

Maybe Tricky will be porting his game as well.

[roland]

...but that's probably because I'm the only person that has ever used this!

Nope, I use DNLOAD regularly and UPLOAD very very very sometimes. When writing a larger programme for the Atom it's nicer to work on my Mac and then download the executable code to the Atom.

[roland]

I have ordered a Spartan board to do some experiments. Because most people want an Atom with a real CPU, VIA etc I do not want to implement these in the FPGA as well but I am considering to implement the glue logic (CPLD's) into this FPGA - that would reduce the total costs and make the board design a bit easier. And that solves the problem of getting the CPLD's.

Maybe it's even possible to make arrangements to prepare the main board for working with of without the 6502, memory and 8255 for those people who want an FPGA Atom only.

[roland]

I have been doing some counting about the pins and the FPGA module has enough I/O ports for replacing the Godil and the two CPLD's. The module has 72 I/O ports and I need 70 ports. I will soon try to merge my CPLD code into the Atom Godil files and check if that still compiles without errors...

It will take at least four 74LVC244 and one 74LVC245 level shifters to make the necessary voltage adjustments between the FGPA board and the other (5V) components. I'm still figuring out what the Iout (output current) for the FPGA board - I couldn't find it in the datasheet I have. However, it won't be a great difference in the number of level shifters.

Edit: output current is up to 24 mA.

[roland]

How on earth can a design with 302 warnings still work?

Can I safely ignore these warnings or do I have to tune my ISE application a bit? I'm using ISE 14.7 on Linux and I just cloned the Godil code from github.

[hoglet]

Unfortunately the Xilinx tools are completely rubbish when dealing with warnings. It seems their FPGAs tools are much worse than their CPLD tools in this regard.

I get 289 warnings for this project, mostly unconnected ports, signals not being used, logic being optimised.

But I agree it is a real pain, because some of them may be important.

This is always the problem when using other peoples code (e.g. in this case the 6847 model). The dilemma is whether to go in and fix them or not. Because if you do, and they release a new version it makes it very hard to merge again.

Sorry I can't be more help!

Dave

[roland]

Sorry I can't be more help!

O sure you can be more help

I tried to add my cpld files to the Atom Godil project in ISE but it did not recognise these files. Even when I force an error ( keyword: entyty ) there was no error. How can I add my two sources?

[hoglet]

I tried to add my cpld files to the Atom Godil project in ISE but it did not recognise these files. Even when I force an error ( keyword: entyty ) there was no error. How can I add my two sources?

How exactly did you add the sources?

As well as placing them in the src directory, you need to tell the Xilinx tools about them (with the Add files option) so they get added to the project. At that point they should be visible in ISE.

Then you will need to update the top level design TopRoland.vhd (or create a new one) to instantiate each of CPLD designs:
https://github.com/hoglet67/AtomGodilVi ... Roland.vhd
in the same way it currently instantiates AtomGodilVideo (but probably there will be no Generics).

Then you will been to add all the extra signals to the top level design, and finally to the .ucf file.

Yes, it's a very tedious process.

What you are doing is actually not that common (i.e. merging separate existing designs into one).

Dave

[gob33]

I dont know if some ideas could be taken from the V6Z80P+ retro-computer by Phil Ruston of retroleum.co.uk
Project ended in 2014 but globaly could have same architecture by replacing the Z80 by a 6502. Uses a PIC for I/O.
Also, I dont see why you want to place the board inside an Atom case cutting the original pcb, why not external with a PC keyboard ?

Wiki
Project zip

Videos;
The Z80 project
The FLOS operating system for OSCA on the V6Z80P

[Elminster]

The point was to use original parts where possible. And then put it in an original case where the original pcb was beyond repair or had no pcb. I.e. to end up with some as close to the original atom as feasible. Rather than just build another single board machine.

[gob33]

Yeah, but i will never cut my Atom board to install anything, this is sacrilege.
Your project is restricted to few people having parts or beyond repair.
You should reconsider it for a wider audience and new people come to Atom / Bbc

[Elminster]

Yeah, but i will never cut my Atom board to install anything, this is sacrilege.
Your project is restricted to few people having parts or beyond repair.
You should reconsider it for a wider audience and new people come to Atom / Bbc

Well Roland has asked for suggestions so he may use you info for his project, I was merely pointing out that he wanted to keep as close to original as possible. I don’t myself own an Atom so if/when I get my board I will leave it caseless, although might be interesting to squeeze it into the checkmate plus kickstarter case.

[hoglet]

Yeah, but i will never cut my Atom board to install anything, this is sacrilege.
Your project is restricted to few people having parts or beyond repair.
You should reconsider it for a wider audience and new people come to Atom / Bbc

As I think you know, because we talked about it in another thread. there are other options for people including AtomFPGA. This has been ported to several platforms, including:
- Papilio One
- Papilio Duo
- Altera DE1
- MyStorm BlackIce
- ZX-Uno

Roland's Atom 2k14 and 2k18 take different approach, and (for me) are more authentic as they retains more of the character of the original atom.

It absolutely does not require an original Atom board to make the keyboard - see my build for example:
http://stardot.org.uk/forums/viewtopic. ... 40#p109091
http://stardot.org.uk/forums/viewtopic. ... 40#p109690

Dave

[gob33]

Burning or welding a PCB are out of my material possibilities like most users.
Commercial FPGA cards do not interest me.
I should want a custom board that can run Atom and Bbc with more advanced possibilities (sound, graphics, text mode).
FPGA + 6502/6512 + ???? could be a solution.
The Atom keyboard is always a problem. I would stuck to a standart PC keyboard with its scan codes recognized inside software.

[roland]

There is already a solution for this:

viewtopic.php?f=44&t=10091
viewtopic.php?f=44&t=10183

This connects to a PS/2 keyboard and translates the key strokes to the Atom keyboard matrix

[gob33]

Interesting, I never saw these posts before.

[bprosman]

What I wonder about is why do these "Alternative keyboard" emulate switches, why not "reading" the 7445 and injecting a column signal into the 8255. Timing wise a little more tricky but then can be done with just one microcontroller.

[gob33]

EMSproto is a french company that can produce a pcb with mountong components.
Just provide the pcb (gerber), an .xls file of all your components and you get an online quotation. Pay with Paypal. Prices by quantity.

[oss003]

What I wonder about is why do these "Alternative keyboard" emulate switches, why not "reading" the 7445 and injecting a column signal into the 8255. Timing wise a little more tricky but then can be done with just one microcontroller.

Phill developed such boards for the Electron, BBC and Atom IIRC.

Greetings
Kees

[jgharston]

Roland's Atom 2k14 and 2k18 take different approach, and (for me) are more authentic as they retains more of the character of the original atom.
It absolutely does not require an original Atom board to make the keyboard - see my build for example:
http://stardot.org.uk/forums/viewtopic. ... 40#p109091
http://stardot.org.uk/forums/viewtopic. ... 40#p109690

By coincidence, I was looking for something almost exactly this. Some months ago I had a start layout out a keyboard PCB, then paused while looking for prices for short run PCB fabs. Turns out (from memory) it's something like one inch over a standard size, so costs silly money. £80 or so comes to mind.

As I don't have any Gerber software (I do all my PCBs with Paint Shop Pro) I can't get proper quotes as fabs inist on Gerber files for anything over a couple of square inches. (Eg Norwich Circuits converted my IDE interface for a tenner on top of the fab prices as it was so simple).

[hoglet]

Hi Jonatham

By coincidence, I was looking for something almost exactly this. Some months ago I had a start layout out a keyboard PCB, then paused while looking for prices for short run PCB fabs. Turns out (from memory) it's something like one inch over a standard size, so costs silly money. £80 or so comes to mind.

I just put the dimensions of my Atom PCB (12.5cm x 37cm) into pcbshopper.com.

The cheapest was JLCPCB which came in at £32.50 for 5 boards, including postage, registered air mail.

The design was done in DipTrace, and I could easily generate some gerbers for you.

Dave

[Kazzie]

Is the Atom's keyboard effectively an ASCII keyboard built in to the main board? If it is, and if you go as far as getting some keyboards made, I'd be interested in one to adapt for my System replica.

[hoglet]

Is the Atom's keyboard effectively an ASCII keyboard built in to the main board? If it is, and if you go as far as getting some keyboards made, I'd be interested in one to adapt for my System replica.

The Atom keyboard is quite different to the Acorn System keyboard. It's effectively just a key matrix, with the conversion to ASCII being done in software by the Atom.

Dave

[Kazzie]

Is the Atom's keyboard effectively an ASCII keyboard built in to the main board? If it is, and if you go as far as getting some keyboards made, I'd be interested in one to adapt for my System replica.

The Atom keyboard is quite different to the Acorn System keyboard. It's effectively just a key matrix, with the conversion to ASCII being done in software by the Atom.

Dave

Bah, it figures.
Tangentially, any idea on where to get keycaps with non-PC labels on them, for Atom or System?

[hoglet]

Tangentially, any idea on where to get keycaps with non-PC labels on them, for Atom or System?

An old BBC Model B keyboard?

[Kazzie]

Tangentially, any idea on where to get keycaps with non-PC labels on them, for Atom or System?

An old BBC Model B keyboard?

I'd prefer to fix a Beeb rather than cannibalise it!
One option I've considered is a set of blank keycaps (e.g. from eBay), but then I'd need to label them somehow.