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#rc2014

9 posts7 participants0 posts today
Public *
0x10f

I designed an address decoder for the #RC2014 that uses two 7400 ICs instead of a 74138. Reading any I/O port between 0x00-0x7f should return the state of the button in the least significant bit. 74125 /1OE should be low if RC2014 /IORQ and A7 are low and /M1 and /WR are high.

Edit: forgot the 100 nF capacitor.

a circuit diagram with RC2014, 2 * 7400, 74125, button, 10k resistor
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Wintermute_BBS

Out there, in the worrying world of today is a little #Zilog #Z80 computer with a mere 64KB of #RAM and running the #1970s CP/M operating system.

This little machine is connected to the #intertubes and it's serving a #singleuser #bulletinboardsystem for you, the worrying souls of #yesteryears to visit.

Take a break from today, connect like it's 1985 - here on RC-BOX BBS, the world's first and (currently) only #rc2014 based bulletin board system in the world!

Check out the #alttext or my #profile info for information on how to connect.

#bbs
#rc2014bbs
#rcbox

This screenshot features the ASCII Art welcome banner of RC-BOX BBS. The technical specs of the system are listed as well as an ASCII UFO which is sending a beam down to the specs listed. All in plain ASCII text. If you want to visit, use a VT100 capable Telnet client and connect to: rc2014.ddns.net:2014
Public
Robert Price

I reworked my Z80 assembly language code last night and this is the result. My #RC2014 computer can now print to the Alphacom 32 printer.

This printer was originally designed for the ZX81 and ZX Spectrum and uses bit bashing to tell the printer whether to print a pixel or not as the print head moves along the paper.

I’m very pleased with this.

Public
0x10f

I designed a new version of my keypad adapter for the RC2014. The second circuit diagram is more detailed and mimics the layout of my breadboard.

Parts: four 10k resistors, 100nF capacitor, four diodes (e.g. 1N4448), 7495, 74125, 74138, matrix keypad with 4*4 buttons.

To read one row of the keypad:
1) Write 1, 2, 4 or 8 to any I/O port between 0x00-0x1f.
2) Read a byte from any of those I/O ports. The 4 least significant bits correspond to buttons on that keypad row.
#RC2014

a high-level (abstract) circuit diagram; signals: RC2014 /M1, /IORQ, /WR, A7-A5 to 74138 EN1, /EN2, /EN3, S2-S0; RC2014 D3-D0 to 7495 P3-P0; +5V to 7495 LD//SH; 74138 /Y0 to 7495 LDCLK; 74138 /Y4 to 74125 /1OE-/4OE; 7495 Q3-Q0 to keypad rows; keypad columns to 74125 4A-1A; keypad columns to ground via 10k resistors; 74125 4Y-1Y to RC2014 D3-D0; capacitor between ground and +5V
a low-level (detailed) circuit diagram; see the first image for signal descriptions
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Gareth Halfacree

Now that April Fool's morning is well and truly over, I'm pleased to confirm that @rc2014 isn't pulling your leg - well, not about the existence of the #RC2014 Mini II Picasso, at least.

oldbytes.space/@rc2014/1142615

How do I know? Here's my hands-on review of the thing. Spoiler: it's *lovely*.

hackster.io/news/science-art-a

Close up of a corner of a yellow PCB. Amongst the squirly tracks is the RC2014 logo. A comically large red LED and green resistor are visible, along with a spiral resistor staircase . The chips are arranged at an angle that it looks like they are thrown there at random rather than being arranged. One has even fallen through the PCB.
OldBytes Space - MastodonRC2014 (@rc2014@oldbytes.space)Attached: 4 images I read a report recently that confirmed that straight PCB traces, right angle, and orthogonally placed components can actually make electrons sad and slow them down. They much prefer the excitement of whizzing along curvy traces, particularly if they end up going in to a chip at a random angle. And bright colours really make them want to work harder. So I will be updating all #RC2014 kits with design philosophy. The first to be done is the RC2014 Mini II Picasso. You can pick one up now at #z80kits https://z80kits.com/shop/rc2014-mini-ii-picasso/
#VintageComputing#RetroComputing#Electronics
Public
RC2014

I read a report recently that confirmed that straight PCB traces, right angle, and orthogonally placed components can actually make electrons sad and slow them down. They much prefer the excitement of whizzing along curvy traces, particularly if they end up going in to a chip at a random angle. And bright colours really make them want to work harder.

So I will be updating all #RC2014 kits with design philosophy. The first to be done is the RC2014 Mini II Picasso. You can pick one up now at #z80kits
z80kits.com/shop/rc2014-mini-i

Close up of a corner of a yellow PCB. Amongst the squirly tracks is the RC2014 logo. A comically large red LED and green resistor are visible, along with a spiral resistor staircase . The chips are arranged at an angle that it looks like they are thrown there at random rather than being arranged. One has even fallen through the PCB.
A different view of the same PCB, but this time in red but with a yellow barrel jack socket, green LED and white header. The spiral resistor staircase can be seen rising up from the board.
Looking down at an RC2014 Mini II Picasso in green this time. The jumble of chips and resistors looks almost chaotic
A view of the PCB from below, but this time in white. The RC2014 sits between the pins of the RAM and UART, but because the chips are at different angles, the logo has to be bent in the middle. The underside of a chip with its legs splayed out can be seen hanging on to the board.
Public
RC2014

I think most of you that are interested in #RC2014 stuff are already subscribed to the RC2014 Newsletter. Which is great because I am really excited with the content of the one coming out next week.

If you're not subscribed, and would like a roundup of exciting RC2014 news in your inbox once a month or so, you can subscribe here rc2014.us13.list-manage.com/su

rc2014.us13.list-manage.comRC2014RC2014 Email Forms
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