Creating a Atomic Chess Board...

discussion of games, software, hardware & emulators relating to the Acorn Atom
User avatar
Multiwizard
Posts: 1180
Joined: Wed Jan 11, 2012 9:03 pm
Contact:

Creating a Atomic Chess Board...

Postby Multiwizard » Sun Jun 11, 2017 9:56 am

Hi,

a few years ago I had a new hardware idea for the Atom... :idea:

It is very time-consuming to make and when it's finished it's totally useless... :mrgreen:

Unless someone decides to (re)write a program for it... 8)

So these are only the pics of phase one... :shock:


After the meeting yesterday I am gonna modify it again, phase two... :mrgreen:

Kees told me if I wanted to make it work I had to make some confirm buttons for every move and a RESET button,, so I will... :D


Greetings, Wim... :-)
Attachments
1.jpg
Aliexpress delivery... (12 Jan 2017)
2.jpg
Lots of it...
3.jpg
Clay...
4.jpg
A total of almost 9 meter of 1mm VD wire...
5.jpg
Stripped...
6.jpg
Lots of wire tinning...
7.jpg
Rin Tintin,,, a lot of tin...
8.jpg
8 meters of white shrink stockings/tubes...
9.jpg
The railroad track... LOL
10.jpg
Some other colours too...

User avatar
Multiwizard
Posts: 1180
Joined: Wed Jan 11, 2012 9:03 pm
Contact:

Re: Creating a Atomic Chess Board...

Postby Multiwizard » Sun Jun 11, 2017 9:59 am

#2...
Attachments
11.jpg
4k7...
12.jpg
The clay templates/molds...
13.jpg
Picture frame...
14.jpg
A railway... 8-|
15.jpg
Preparing PL6 #1...
16.jpg
Preparing PL6 #2...
17.jpg
I needed some staws... :-D
18.jpg
Improvising #1...
19.jpg
Improvising #2...
20.jpg
Improvising #3...

Isn't it neat? :-D

User avatar
Multiwizard
Posts: 1180
Joined: Wed Jan 11, 2012 9:03 pm
Contact:

Re: Creating a Atomic Chess Board...

Postby Multiwizard » Sun Jun 11, 2017 10:04 am

#3
Attachments
21.jpg
Using several small magnets...
22.jpg
Phase one...
23.jpg
Board position addresses...
24.jpg
Reed#1...
25.jpg
Reed#2...
26.jpg
Over view Row One...
27.jpg
Tinning wires...
28.jpg
29.jpg
30.jpg
Blue...
Last edited by Multiwizard on Sun Jun 11, 2017 10:09 am, edited 2 times in total.

User avatar
Multiwizard
Posts: 1180
Joined: Wed Jan 11, 2012 9:03 pm
Contact:

Re: Creating a Atomic Chess Board...

Postby Multiwizard » Sun Jun 11, 2017 10:07 am

#4
Attachments
31.jpg
Risistors...
32.jpg
Resistors packing...
33.jpg
Red & Bleu...
34.jpg
Reed Overview...
35.jpg
Wiring #1...
36.jpg
Wiring #2...
37.jpg
Test #1 Calibrating...
38.jpg
Phase 1 is complete, this will never work the way I want to... :-(

But,,, up to phase 2...
39.jpg
Phase 2...

Kees​ told me I had to do this... (see pic)

Making 2 confirm buttons and a RESET button...

So, to be continued...

User avatar
IanS
Posts: 458
Joined: Mon Aug 31, 2009 6:02 pm

Re: Creating a Atomic Chess Board...

Postby IanS » Sun Jun 11, 2017 10:36 am

Phase 2 needs diodes to avoid ghosting.
http://pcbheaven.com/wikipages/How_Key_Matrices_Works/

User avatar
Multiwizard
Posts: 1180
Joined: Wed Jan 11, 2012 9:03 pm
Contact:

Re: Creating a Atomic Chess Board...

Postby Multiwizard » Sun Jun 11, 2017 3:51 pm

IanS wrote:Phase 2 needs diodes to avoid ghosting.
http://pcbheaven.com/wikipages/How_Key_Matrices_Works/
Hi,

thanks for the advice... :D


Greetings, Wim... :-)

User avatar
Multiwizard
Posts: 1180
Joined: Wed Jan 11, 2012 9:03 pm
Contact:

Re: Creating a Atomic Chess Board...

Postby Multiwizard » Tue Jun 20, 2017 6:13 pm

Hi,

Kees has made me another schematic with these diodes... :D

Looks better this way IanS... :?:


Greetings, Wim... :-)
Attachments
Chess Schematic #2.PNG

User avatar
IanS
Posts: 458
Joined: Mon Aug 31, 2009 6:02 pm

Re: Creating a Atomic Chess Board...

Postby IanS » Tue Jun 20, 2017 8:31 pm

Diodes look the wrong way round.

Each column is pulled high normally via the resistors. When each row output of the 7445 goes low, you want to be able to pull the row low via a switch and a diode. So the diode wants to pointing away from the column wire towards the row output signal.

Have I misunderstood how it works?

User avatar
roland
Posts: 2777
Joined: Thu Aug 29, 2013 8:29 pm
Location: Born (NL)
Contact:

Re: Creating a Atomic Chess Board...

Postby roland » Tue Jun 20, 2017 8:46 pm

You are right. With the diodes this way around the switches can't pull the inputs to a low level. The diodes will block the current.

Btw ... I am still not convinced why we need the diodes here. There is only one active row (low level) when scanning the switches so imho the other rows cannot pull the inputs low whether the switches are opened or closed.

The Atom keyboard works the same way and I have never noticed some ghosting.

Edit: I reread the theory about ghosting and I am now convinced :) In fact, now I am worried because with the right key presses you can damage the 7445 because you can "short circuit" two outputs. In real life it will survive because the short circuit won't last very long, but still.....
256K + 6502 Inside
MAN WOMAN :shock:

User avatar
hoglet
Posts: 6353
Joined: Sat Oct 13, 2012 6:21 pm
Location: Bristol

Re: Creating a Atomic Chess Board...

Postby hoglet » Tue Jun 20, 2017 9:44 pm

roland wrote:Edit: I reread the theory about ghosting and I am now convinced :) In fact, now I am worried because with the right key presses you can damage the 7445 because you can "short circuit" two outputs. In real life it will survive because the short circuit won't last very long, but still.....

It isn't a problem with the 7445 because the output stage of that device is open collector, so it doesn't matter if two output are shorted. Not sure the same is true of the 74LS45 (or if it even exists?)

What did you end up using in your New Atom?

User avatar
Multiwizard
Posts: 1180
Joined: Wed Jan 11, 2012 9:03 pm
Contact:

Re: Creating a Atomic Chess Board...

Postby Multiwizard » Wed Jun 21, 2017 5:32 am

Ok thanks, so I have to turn round all the diodes ... :D

Now I have to wait for Alie , (100pcs for € 0,72 how do they do it)


Greetings, Wim... :-)

User avatar
roland
Posts: 2777
Joined: Thu Aug 29, 2013 8:29 pm
Location: Born (NL)
Contact:

Re: Creating a Atomic Chess Board...

Postby roland » Wed Jun 21, 2017 7:32 am

hoglet wrote:It isn't a problem with the 7445 because the output stage of that device is open collector, so it doesn't matter if two output are shorted. Not sure the same is true of the 74LS45 (or if it even exists?)
What did you end up using in your New Atom?


Thanks, now I'm not worried any more :lol: I used a 7445 from an old Atom.
256K + 6502 Inside
MAN WOMAN :shock:

User avatar
daveejhitchins
Posts: 3619
Joined: Wed Jun 13, 2012 5:23 pm
Location: Newton Aycliffe, County Durham

Re: Creating a Atomic Chess Board...

Postby daveejhitchins » Wed Jun 21, 2017 7:59 am

roland wrote:Thanks, now I'm not worried any more :lol: I used a 7445 from an old Atom.
There's lot's on eBay, if you get stuck :D

And Dave's correct, there's no 74LS45 listed - except someone on eBay is selling one :lol:

Dave H :D
Parts: UM6502CE, GAL22V10D, GAL16V8D, AS6C62256A, TC514400AZ, WD1772, R6522, TMS27C512, AT28C256
Products: ARA II, ABR, ATI, AP6, MGC, AP5 . . .
For a price list, contact me at: Retro Hardware AT dave ej hitchins DOT plus DOT com

Prime
Posts: 2301
Joined: Sun May 31, 2009 11:52 pm

Re: Creating a Atomic Chess Board...

Postby Prime » Wed Jun 21, 2017 8:48 am

Being open collector, don't you also need pullups? Just checked the Atom keyboard circuit and that does indeed have pullups, unless the 6522 has them internally, I know one of the ports on the 6821 do so might be the case here too :)

It's also worth noting that 74xx145 are also compatible.

Cheers,

Phill.
Last edited by Prime on Wed Jun 21, 2017 8:51 am, edited 1 time in total.

User avatar
oss003
Posts: 2515
Joined: Tue Jul 14, 2009 11:57 am
Location: Netherlands
Contact:

Re: Creating a Atomic Chess Board...

Postby oss003 » Wed Jun 21, 2017 8:50 am

I always have trouble with positioning diodes in the right direction that's why I told Wim to do a test before soldering all 67 of them .......... ;)

Ian was right about ghosting which will probably never happen with a keyboard but is more likely to happen with the chess board.
The problem occurs without diodes when there are pieces at reed relais A1, A2 and B1.
When O6 is going low, it looks like there is a piece on reed relais B2 but there isn't.....

chess3.png

Greetings
Kees

User avatar
hoglet
Posts: 6353
Joined: Sat Oct 13, 2012 6:21 pm
Location: Bristol

Re: Creating a Atomic Chess Board...

Postby hoglet » Wed Jun 21, 2017 1:04 pm

Prime wrote:Being open collector, don't you also need pullups? Just checked the Atom keyboard circuit and that does indeed have pullups, unless the 6522 has them internally, I know one of the ports on the 6821 do so might be the case here too :)

Yes, indeed pull ups should be added to each "column".

User avatar
oss003
Posts: 2515
Joined: Tue Jul 14, 2009 11:57 am
Location: Netherlands
Contact:

Re: Creating a Atomic Chess Board...

Postby oss003 » Wed Jun 21, 2017 1:45 pm

Dave,

are you sure the 7445 has open collector outputs because the function table states Low and High outputs ......

7445.png

Greetings
Kees

User avatar
hoglet
Posts: 6353
Joined: Sat Oct 13, 2012 6:21 pm
Location: Bristol

Re: Creating a Atomic Chess Board...

Postby hoglet » Wed Jun 21, 2017 1:57 pm

oss003 wrote: are you sure the 7445 has open collector outputs because the function table states Low and High outputs ......

I'm pretty sure, yes.

In the TI data sheet there is a picture of the output stage, and it looks like an open collector:
http://www.cnic.ro/ed/ic/SN7445.pdf
7445.PNG

But even if it wasn't, the pull ups would still be needed for the case where no key is pressed.

Dave

User avatar
oss003
Posts: 2515
Joined: Tue Jul 14, 2009 11:57 am
Location: Netherlands
Contact:

Re: Creating a Atomic Chess Board...

Postby oss003 » Wed Jun 21, 2017 2:04 pm

You are right, the 8255 has internal pullup resistors, but why aren't there pullup resistors in the Atom?

8255-.png

Just wondering if Port B of the 6522 also has pullup resistors?

Greetings
Kees

User avatar
roland
Posts: 2777
Joined: Thu Aug 29, 2013 8:29 pm
Location: Born (NL)
Contact:

Re: Creating a Atomic Chess Board...

Postby roland » Wed Jun 21, 2017 2:18 pm

The resistors R17 ... R25 (at the bottom of the picture) are the pull up resistors.

Schermafbeelding 2017-06-21 om 16.18.01 (2).png
256K + 6502 Inside
MAN WOMAN :shock:

User avatar
oss003
Posts: 2515
Joined: Tue Jul 14, 2009 11:57 am
Location: Netherlands
Contact:

Re: Creating a Atomic Chess Board...

Postby oss003 » Wed Jun 21, 2017 3:08 pm

R17-R25 are pullups for the colums to the 8255 but there are no pullups on the rows from the 7445??
Because these are open collector outputs, do they have a stable state if the row is not selected (H)?

Greetings
Kees

Prime
Posts: 2301
Joined: Sun May 31, 2009 11:52 pm

Re: Creating a Atomic Chess Board...

Postby Prime » Wed Jun 21, 2017 3:12 pm

As the datasheet says "all CMOS designs", since the 7445 (or LS45) isn't maybe Acorn found they needed the pullups.

Cheers.

Phill.

User avatar
MartinB
Posts: 4511
Joined: Mon Mar 31, 2008 9:04 pm
Location: Obscurity

Re: Creating a Atomic Chess Board...

Postby MartinB » Wed Jun 21, 2017 3:37 pm

Kees wrote:Just wondering if Port B of the 6522 also has pullup resistors?


I predicated my I2C interface on the assumption that there are internal pull-ups present on the 6522 outputs. The datasheet shows them schematically and I measured the values to be around 1k ohm. (I2C won't work unless there are pull-ups present on the bus lines and I don't use external components on any slave devices.)

6522 output stages.jpg

User avatar
roland
Posts: 2777
Joined: Thu Aug 29, 2013 8:29 pm
Location: Born (NL)
Contact:

Re: Creating a Atomic Chess Board...

Postby roland » Wed Jun 21, 2017 3:54 pm

oss003 wrote:R17-R25 are pullups for the columns to the 8255 but there are no pullups on the rows from the 7445??
Because these are open collector outputs, do they have a stable state if the row is not selected (H)?


They don't have to be pulled up separately. The Atom selects a row and that row goes "low". The other rows are not important at that moment. The resistor of the selected column acts as the pull up also for a non-selected row when a key is pressed on that row. That prevents an occidentally "low" read.
256K + 6502 Inside
MAN WOMAN :shock:

User avatar
oss003
Posts: 2515
Joined: Tue Jul 14, 2009 11:57 am
Location: Netherlands
Contact:

Re: Creating a Atomic Chess Board...

Postby oss003 » Wed Jun 21, 2017 4:06 pm

Ok, so just turning all diodes should be ok for Wim's Atomic Chess schematic.
Thanks .... =D>

Greetings
Kees

User avatar
hoglet
Posts: 6353
Joined: Sat Oct 13, 2012 6:21 pm
Location: Bristol

Re: Creating a Atomic Chess Board...

Postby hoglet » Wed Jun 21, 2017 4:37 pm

MartinB wrote:I predicated my I2C interface on the assumption that there are internal pull-ups present on the 6522 outputs. The datasheet shows them schematically and I measured the values to be around 1k ohm. (I2C won't work unless there are pull-ups present on the bus lines and I don't use external components on any slave devices.)

Just in case you aren't aware, the port B pull ups are not present on the W65C22.
http://archive.6502.org/datasheets/wdc_ ... 3_2010.pdf

Dave

User avatar
MartinB
Posts: 4511
Joined: Mon Mar 31, 2008 9:04 pm
Location: Obscurity

Re: Creating a Atomic Chess Board...

Postby MartinB » Wed Jun 21, 2017 5:17 pm

Ah, cheers, now you mention it, I did know because this has cropped up before but I had also completely forgotten! If I'd thought, I would have put a note in the manual but no worries, I'll add something to the thread. It's not a problem because if someone wants to use a WDC device, it's easy enough to hang a couple of resistors off the bus somewhere and many slave devices have options for the use of resistors. Ta Dave... 8)


Return to “acorn atom”

Who is online

Users browsing this forum: No registered users and 2 guests