Sorted by Squirrels.

Thursday, 15 May 2008

IO, IO it's off to work we go!


This is my 1st attempt at getting a PCB made. It was rushed so please excuse any glaring stupidity :)

A colleague was having some PCBs manufactured and had a little space left on the plate so I knocked this together during a lunch hour. I'm pretty pleased so far - the boards have come back and, despite being less than optimally packed, they're quite neat.



This is a ZX81 IO board. As I'm sure you've already worked out, esteemed reader! The 8255 is a general purpose IO controller and it's mapped to the Z80 IO space at ports 0x07 and 0x17. I'll be attaching the MMC card to it later :)

I've included links to the schematic and board files in case you want to fire up Eagle and have a play. This is a package with a very steep learning curve. I've been playing with it for about a year and I can only now say that I'm beginning to become confident. Version 5 has just been released which adds some polish to the mix. It wouldn't be uncharitable to say that the package weas a little rough around the edges before..! I haven't pushed V5 much - and it's likely I never will :) - but you can just tell that there's been some love and attention lavished. Hurrah for CadSoft!

Click the schematic for a very high res version. Or get the binaries from HERE.

I'll let you know how it works out when the SMT 74s arrive!

Friday, 2 May 2008

Average bits 10.2



May I present some of my non-human babies. Continued thanks go to my employers - you know who you are - for allowing the museum to exist on my desk.

The C128 rear-left has a proto-board built SD2IEC card installed inside the tape drive. I shaped the PCB like a cassette. Press eject and you can insert an SD card into the presented slot. Cheesy but fun :)

The Apple //e front left is my latest baby. I'm awaiting a prototype board from the states so I can build an IDE card. They're ridiculously simple to build, it seems.

The centre column contains a QL, an STe, a Spectrum 128 and a BBC Master 128 with MMBeeb interface. They're nice, but not my favourites. Especially as the Sinclair machines require attention due to defective membranes. A pathology known around these parts as the curse of Clive.

No, the favourite machine honour belongs to the Atari 800. This is another machine with a SD card interface secreted away in a hacked tape drive. I dreamed.. no.. seriously fantasised about this machine when I was pecking away at my ZX81. (Not pictured - it's on the bench at the moment having an SD card and keyboard upgrade, natch)

One thing tends to be common amongst these machines and that's the addition of SD card interfaces.. My hat goes off to the engineers linked in this post. MMBeeb was my first exposure to the practice, which gave me enough of a kick-start to design my own interface for the zx81. Monster maze loads in 6 seconds. Bliss!

I guess it remains to be said - I AM 8-BIT

And proud :)

This is how we do it

MMC (9) acorn atom (7) zx81 (7) arduino (5) Atari 800 (3) c128 (3) sd card (3) sd2iec (3) sio2sd (3) tatung einstein (3) 6502 (2) Chuckie egg (2) M5 (2) Max6956 (2) QL (2) RCM (2) Sord (2) assembler (2) avr (2) c64 (2) cadsoft eagle (2) eeprom (2) einSDein (2) mmbeeb (2) multi-cart (2) spi (2) system 80 (2) ufat2 (2) vic20 (2) video genie (2) 6502 second processor (1) 6522 (1) 8255 (1) Acorn BBC Micro (1) Apple 2e (1) Apple ][ 2 two (1) BBC 6502 second processor (1) BBC micro (1) DevicePrint (1) Double Choc Chip Muffins (1) FAT (1) IO (1) Jupiter Ace (1) LED (1) Master 128 (1) PCB (1) PIC (1) POV (1) PROGMEM (1) ST (1) Spectrum 128 (1) antex (1) arcade spinner (1) arduino shield (1) atari (1) atmel (1) bakewell tart (1) beer (1) bird's nest (1) bitbucket (1) brokenated XC special (1) cake (1) cassette (1) cassette interface (1) compact flash (1) convert (1) dac (1) de-yellowing (1) eaca (1) efficient (1) einsdein. z80 (1) eye strain (1) failosophy (1) filesystem (1) finally (1) fram (1) french polishing (1) fuse (1) fuses (1) gaming (1) github (1) glue (1) google chrome (1) heroic failure (1) high voltage programming (1) hot irons (1) if (1) jiffydos (1) joey beltram (1) lego robot (1) library (1) lying (1) machine code (1) matron (1) microcode (1) mmc interface (1) mmc2iec (1) mmm (1) mouse guts (1) multicart (1) oscilloscopes (1) pcm (1) pic32mx (1) porn (1) proto shield (1) purple (1) repo (1) retro computer museum (1) retro hard-on (1) rom box (1) sd (1) sd2mmc (1) seadragon (1) silliness (1) small (1) software master (1) soldering (1) sord m5 (1) spi software master (1) stray capacitance (1) string (1) techadventure (1) test equipment porn (1) ts1000 (1) turtle cheesecake (1) tweaking (1) vc20 (1) video head (1) video ram replacement (1) weewee (1) wingasm (1) wire library (1) wodges of IO (1) xilinx cpld (1) yellowing (1) zx spectrum (1) zxpander (1)

About Sir Morris

My photo

Loves: Old computers, Old Techno, Old ladies. Cake.
Hates: New computers.

Unless otherwise stated all of the original work presented here is:

Creative Commons License
Licensed under a Creative Commons Attribution-Noncommercial 2.5 Generic License.

The work of others where referenced will be attributed appropriately. If I've failed to do this please let me know.