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Vintage Computers Any vintage computer systems, calculators, video games etc., but with an emphasis on 1980s and earlier equipment.

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Old 2nd Aug 2021, 7:55 pm   #61
Timbucus
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Default Re: MK14 Programming Interface

On a serious note Phil's created an uploader for the Elf which can be seen here....

http://www.mccrash-racing.co.uk/phil...elf_keyer2.pdf

This uses the same technique as I did when I adapted this one for the Triton of making the lines pullups that you pull down so I can modify my extended board to do the same thing. If and when we get a larger version of this with more opto's then it will be another machine in its armoury if I can get it working. If not then I will build one of Phil's devices.
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Old 2nd Aug 2021, 7:58 pm   #62
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Default Re: MK14 Programming Interface

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Originally Posted by SiriusHardware View Post
Well, Tim is a genuine text adventure Grue... er, I mean... Guru... and also a bit of an SC/MP nut so it's hard to imagine anyone better equipped to try.

Problem is, like you, he always seems to have far too many plates spinning. We'll probably have to let him repair that Heathkit machine first.
Like the reference... thanks - I did actually put the H9 on the bench with scope and tools/diagrams in front about 10am this morning on my day off and here I am just pressing pay on the last order to get bits to complete the kits of parts for the OrtonView, Elf and Uploader - sometimes you have to prioritise and the Ortonview is one I want to get going so that I can modify my other one to be a Scrumpi screen...

I suspect the H9 will be a longer term project.
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Old 2nd Aug 2021, 8:01 pm   #63
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Default Re: MK14 Programming Interface

Quote:
I still think a real scanned keyboard addon on the port is the best though as it will be authentic to the time
Yes, but I am terminally lazy. If there's one electronics task I detest more than anything else, it's wiring up and then legending keyboards. And there are hundreds of thousands of old, unwanted, working, PS/2 keyboards lying around with their keys already wired up and legended.

I know this is one thing I won't be able to persuade you on, though, and it's true that anything like that would be a decidedly non-period feature.
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Old 2nd Aug 2021, 8:18 pm   #64
Timbucus
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Default Re: MK14 Programming Interface

Quote:
Originally Posted by SiriusHardware View Post
Quote:
I still think a real scanned keyboard addon on the port is the best though as it will be authentic to the time
Yes, but I am terminally lazy. If there's one electronics task I detest more than anything else, it's wiring up and then legending keyboards. And there are hundreds of thousands of old, unwanted, working, PS/2 keyboards lying around with their keys already wired up and legended.

I know this is one thing I won't be able to persuade you on, though, and it's true that anything like that would be a decidedly non-period feature.
You can buy cherry keycap sets for 5 and discard most keys - if someone laid out a PCB for cherry keys we could probably simplify construction quite a bit.
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Old 2nd Aug 2021, 8:19 pm   #65
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Default Re: MK14 Programming Interface

In fact it could repeat the edge connector for a PI uploader or even have one built in...
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Old 2nd Aug 2021, 8:48 pm   #66
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Default Re: MK14 Programming Interface

Quote:
Originally Posted by Timbucus View Post
Quote:
Originally Posted by SiriusHardware View Post
Quote:
I still think a real scanned keyboard addon on the port is the best though as it will be authentic to the time
Yes, but I am terminally lazy. If there's one electronics task I detest more than anything else, it's wiring up and then legending keyboards. And there are hundreds of thousands of old, unwanted, working, PS/2 keyboards lying around with their keys already wired up and legended.

I know this is one thing I won't be able to persuade you on, though, and it's true that anything like that would be a decidedly non-period feature.
You can buy cherry keycap sets for 5 and discard most keys - if someone laid out a PCB for cherry keys we could probably simplify construction quite a bit.
Well that's weird because I discovered (by watching Atomic Shrimp's latest video) you could get cherry MX style keycaps with a transparent cap you can put a legend under, and bought 40 caps and 20 MX switches to make a proper keyboard for my MK14 because I am having so many problems with keybounce on my MK14. I also found out KiCAD has footprints for all the MX key switch cap shapes, so laying out a keyboard would be simple.

Thinking about it for the MK14 I was thinking you could make a SCRUMPI3 style keyboard with ~40 keys and several shifts to save on keys and scanning time while retaining dedicated MEM TERM ABORT and GO keys.

I have a funky coloured PS/2 keyboard so another idea was to make a PS/2 to MK14 interface using one of my uploader boards and a microcontroller to make a simple keyboard interface, with a programmable mapping of PS/2 keys to MK14 keys. My only worry about all this is that the MK14 has a very limited memory so how much use I could make of it.
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Old 2nd Aug 2021, 9:05 pm   #67
SiriusHardware
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Default Re: MK14 Programming Interface

As a first step, do you know the 'key14' test utility which comes with the uploader 'software' package - if you run that up and use the Pi's keyboard (actual or remote, via SSH) to 'press' MK14 keys, do they ever bounce in the same way as your keys do when you are using the physical keys?

Connect any other momentary contact switch across the 'Mem' row and column on the edge connector and use that to step through the memory locations - does it bounce - skip locations sometimes - if you do that?

Does the extent to which this happens change when the interface is / is not connected? I have only ever used the TLP185 optos in my own interfaces so I can't say whether your PC817s will completely let go of the keypad lines when turned off. However, I think you originally had this problem before you even built the uploader.

As far as I know I'm using the exact same hardware in my issue VI -except- that I am using Omron branded low Newton force tact switches which were bought through Farnell. I can't say I have ever experienced problems with switch bounce.

Didn't Mark have something similar until he replaced ...mmmm... the 7445? Are you using a 'plain' 7445?
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Old 2nd Aug 2021, 9:08 pm   #68
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Default Re: MK14 Programming Interface

Yes I also wonder with so many fakes around is it a real 7445?
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Old 2nd Aug 2021, 9:15 pm   #69
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Default Re: MK14 Programming Interface

Quote:
Originally Posted by Slothie View Post
Quote:
Originally Posted by Timbucus View Post
Quote:
Originally Posted by SiriusHardware View Post

Yes, but I am terminally lazy. If there's one electronics task I detest more than anything else, it's wiring up and then legending keyboards. And there are hundreds of thousands of old, unwanted, working, PS/2 keyboards lying around with their keys already wired up and legended.

I know this is one thing I won't be able to persuade you on, though, and it's true that anything like that would be a decidedly non-period feature.
You can buy cherry keycap sets for 5 and discard most keys - if someone laid out a PCB for cherry keys we could probably simplify construction quite a bit.
... so laying out a keyboard would be simple.

Thinking about it for the MK14 I was thinking you could make a SCRUMPI3 style keyboard with ~40 keys and several shifts to save on keys and scanning time while retaining dedicated MEM TERM ABORT and GO keys.
Great news so it is just the layout to agree then . My plan was to hook up my SCRUMPI3 keyboard I have made to my MK14 to test the scanning software.

I had not planned on repeating the Function keys externally just a proper ASCII (well MK14 VDU charset) for the MK14 long term i.e. what they would have needed to run a version of NIBL in Page1 - the MK14 remains a number/function pad beside it.

I assume it would be a routing nightmare to map the existing keys so it acts as both a full ASCII and supported in SCIOS... it would be interesting though.
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Old 2nd Aug 2021, 9:26 pm   #70
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Default Re: MK14 Programming Interface

Well you could have the MEM TERM GO keys be M T and G with ESC for ABORT... 0..9 mapped as before and symbols as shifted numbers. Maybe use RETURN as TERM rather than T.
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Old 2nd Aug 2021, 9:27 pm   #71
SiriusHardware
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Default Re: MK14 Programming Interface

You could map 0-9 A-F as they are on the standard keypad and map all the other alpha characters etc into the currently unused row / column positions and sort it all out using a lookup table embedded in whatever RAM based application will be reading the full keyboard. Assuming outboard RAM mapped at 0200-07FF, of which 512 bytes is dedicated as screen RAM, the system will have 1K + 640 bytes of RAM for your word processor / terminal program to run in. Slightly more than a basic ZX81.
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Old 2nd Aug 2021, 9:56 pm   #72
Timbucus
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Default Re: MK14 Programming Interface

Assuming we could make enough space in the NIBL ROM to have the lookup table and the scan code those might be a really interesting way to do it. RETURN as TERM is a good idea but, ESC as ABORT may not be depending on how we map the full ASCII set as we will need two SHIFTS (CTRL and SHIFT maybe) so maybe DEL as being a useful key to stand alone doubles as ABORT.

We need to scribble on a copy of the current grid layout... oh look

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Old 2nd Aug 2021, 10:01 pm   #73
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Default Re: MK14 Programming Interface

How we map that to a physical layout that can be done with a double sided board though....

I assume the Shifted chars would be best using the Spectrum layout as muscle memory would remember where they were as otherwise custom keycaps would be needed.
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Old 2nd Aug 2021, 10:04 pm   #74
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Default Re: MK14 Programming Interface

Blast missed SPACE - maybe instead of DEL (So is Abort) - using the ZX81 layout as Keycaps are likely to be around for that.
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Old 2nd Aug 2021, 10:14 pm   #75
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Default Re: MK14 Programming Interface

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Originally Posted by Timbucus View Post
Blast missed SPACE - maybe instead of DEL (So is Abort) - using the ZX81 layout as Keycaps are likely to be around for that.
Or you could use these or something similar

Do we have a reasonable picture of the SCRUMPI3 key layout? I tried looking about on the forum but couldn't see anything.
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Old 2nd Aug 2021, 10:47 pm   #76
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Default Re: MK14 Programming Interface

This is the best I have and my repro...

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Old 2nd Aug 2021, 11:27 pm   #77
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Default Re: MK14 Programming Interface

Hmm I wonder what the "User" key was for - some kind of 'Fn' key? Its pretty impressive to get all that into 21 keys. I presume the "Int" key was connected to interrupt, or was the equivalent of a break key.
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Old 2nd Aug 2021, 11:30 pm   #78
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Default Re: MK14 Programming Interface

As for your diagram above, you could get away with only 1 shift key and use the other as space. You could always have 2 physical shift keys wired in parallel for convenience.
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Old 3rd Aug 2021, 7:00 am   #79
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Default Re: MK14 Programming Interface

I prefer that idea to the SC-3 keypad which looks hardly any better than a dumbphone keypad. I wouldn't want to be typing text on that for any length of time.

I agree there hardly seems a need for two electrically separate shift keys when there is only upper case available in the character set.
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Old 3rd Aug 2021, 7:47 am   #80
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Default Re: MK14 Programming Interface

Writing NIBL programs using T9 predictive text would be an interesting challenge. Maybe a version optimized for NIBL keywords. That would also avoid using multiple shift keys and might even be easier than using the scrumpi 3 keypad.
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