WMPLAY while a song plays: the folder \MUSIC\SYNTH on the left with the bar on 02 Neon Harbor.mp3, on the right the name of the song, Playing 01:23, the volume, the spectrum, the two level meters and the line File 2 of 9
IBM PS/2, WonderMCA

WonderMCA: an MP3 player and Bluetooth headphones for your PS/2

/ / IBM PS/2, WonderMCA

Your PS/2 now plays MP3 files, and its sound can go to Bluetooth headphones. The WonderMCA decodes the MP3 files of its microSD card or USB stick by itself, and it can send everything it plays (Sound Blaster, AdLib, Gravis UltraSound, CD audio and now MP3) to a Bluetooth headset or speaker instead of the jack. The Bluetooth game pads got better too: more pads, steadier links.

WMPLAY while a song plays: the folder of the microSD card on the left with the bar on 02 Neon Harbor.mp3, on the right the name of the song, Playing 01:23, the volume, the spectrum, the two level meters and the line File 2 of 9
WMPLAY, the new full-screen MP3 player for DOS, while a song plays.

An MP3 player inside the card

The card reads and decodes the MP3 file itself. The PS/2 only gives the orders: play, pause, next. It does not read the file and it does not decode it, so its processor does not matter, and a game or a DOS program keeps running while the music plays. The music is mixed with the other sounds of the card and comes out of the … Read the rest

IBM PS/2, WonderMCA

WonderMCA goes wireless: Bluetooth keyboards, mice and game pads for your PS/2

/ / IBM PS/2, WonderMCA

Your PS/2 can now go wireless. With the Bluetooth firmware, the WonderMCA pairs Bluetooth keyboards, mice and game pads, both Classic Bluetooth and Bluetooth Low Energy, and hands them to the PS/2 as the hardware it has always known: its own keyboard, a serial mouse and a joystick on the game port. No dongle, and nothing to install on the PS/2.

The WonderMCA BIOS Bluetooth page during a keyboard pairing: "Type this code on the keyboard, then press Enter: 004271", 52 seconds left
A keyboard pairs: type the code on the Bluetooth keyboard itself.
The WonderMCA BIOS Bluetooth page after a pairing: "Status : Ready - 1 connected", a DualShock 4 Wireless in Paired devices, connected
A game pad paired and connected.

What the PS/2 sees

The card does all the Bluetooth work. The PS/2 never talks Bluetooth: each device arrives through a path that DOS and its programs already know.

  • Keyboard: it is the PS/2’s own keyboard. The card sends the keys to the keyboard controller of the PS/2, so national layouts with KEYB, Ctrl-Alt-Del and the repeat of a held key work as usual. A Bluetooth keyboard and a USB
… Read the rest
AppleII, SmartdiskII

Introducing SmartDisk XL

/ / AppleII, SmartdiskII

The SmartDisk family is growing. Meet the SmartDisk XL, a fully redesigned version of the SmartDisk floppy emulator. It’s built on the same proven firmware, with a stronger board around it.

What’s new

  • New PCB design. The board has been redrawn from scratch for the XL.
  • 1.54″ OLED screen. It’s bigger and sharper than before, so disk images and menus are easier to read at a glance.
  • New routing with a stronger power source. The power path has been reworked to give the board more headroom and more stable operation.
  • Rotary switch. You can scroll through your disk images and select one with a single knob, so navigation is quicker and more natural.

What stays the same

The SmartDisk XL runs the same firmware as the SmartDisk II, with exactly the same capabilities. Everything you know about using SmartDisk works on the XL as it is, and existing documentation … Read the rest

AppleII, SmartdiskII

SmartDisk II now speaks Macintosh: MOOF images, in read and write

/ / AppleII, SmartdiskII

The SmartDisk II is no longer an Apple II only story. With the latest firmware, the same little board plugs into the external floppy port of a Macintosh and becomes an external 800K drive: it boots, reads, writes and even initializes disks, straight from images on an SD card.

A Macintosh SE with the SmartDisk II plugged into its external floppy port
The SmartDisk II in its case, with the ribbon cable

Give your Macintosh a working floppy drive again

Many compact Macs still work perfectly, but their floppy drive no longer does, and the original disks are long gone or unreadable. The SmartDisk II solves both problems at once: it plays the part of an Apple external 800K drive, and your disks are now files on an SD card.

  • Boot the Macintosh from a disk image: leave the internal drive empty and the Mac starts from the SmartDisk II.
  • Read and write: copy files, save documents, and Initialize a blank disk from the Finder. Everything the Mac writes goes back into
… Read the rest
IBM PS/2, WonderMCA

WonderMCA – The SmartDrive ghost, 4 MB of extra RAM, a CPLD that reprograms itself, and a Server 95 running DOOM

/ / IBM PS/2, WonderMCA

Where we were

Since the summer WonderMCA has worked on every PS/2 I own… as long as you did not look too closely at the 386DX machines. On the 286 and 386SX boxes (8550Z, 8555, 8556, 8557) the card was solid. On the Model 70 (8570), the same card, the same firmware and the same CPLD produced a slow drip of problems that never pointed at anything:

  • at power-on the BIOS sometimes said “Memory change: Reset the RAM Config”, meaning the card’s configuration block had been changed behind its back;
  • DIR C: could reboot the machine;
  • loading a 67 KB .EXE from the emulated floppy rebooted the PC before the program even started.

This post is the story of the last few weeks. It covers five things that turned out to be linked more than I expected:

  1. finding the real cause of the 8570 instability (spoiler: SmartDrive, and four
… Read the rest
Uncategorized

WonderMCA – REV8 a new hope

/ / Uncategorized

On this project, I have so far made 2 prototype versions of the PCB, the REV2 and the REV5. The REV2 was a real draft with no CPLD to manage the MCA bus constraints, and it was a good base with all the MCA signals available on PIN Header to prototype what was supposed to be a solid version (REV5). The PCB Revision 5 is using an ATF1508 in PLCC84 format, and was supposed to be working smoothly but it was clearly not the case.

I made several mistakes on the Rev5:

  • JLCPCB 10K resistors wrong 0603 reference giving 1K8 instead of 10K,
  • TC2050 CPLD upload connector missing +5V from the board (as buried in the programmer reference document)
  • Wrong footprint on the LDO (Power supply) of the DAC circuit,

All these should be fix with the REV8 of the board… But it is not the main issue of the … Read the rest

Uncategorized

WonderMCA – Adding data bit on the BUS

/ / Uncategorized

Part of the REV4 revision of the WonderMCA board objective was to introduce 16Bit data Bus instead of 8Bit.All the PS/2 MCA Bus are able to handle 16Bits data slave along with 24Bits address lines. The expected outcome is to double the MEM & IO bandwidth and thus increase the native disk transfer.

The new board revision provides now 2 SN74CB3T3245DWR to cover DO-15 data lines, following the same multiplexing logic to the RP2350.

When D_OE signal is asserted (LOW), then A_OE is HIGH and the 2 SN74CB3T3245DWR are active to read or write data on the MCA bus according the cycle type (MEMR,MEMW,IOR,IOW)

Reading carefully the MCA sepcification the following new signals needs to be handle both by the CPLD and by the RP2350

  • /CD_DS_16n: This signal is an active LOW signal (Totem Pole), per MCA slot, slave driven, that defines when a slave is able to perform a
… Read the rest
IBM PS/2

WonderMCA: Gone before we looked, the Model 57’s early /CD-SETUP and the POS register that never answered

/ / IBM PS/2

The card that vanished from setup

WonderMCA had been enumerating cleanly across the PS/2 matrix for weeks. POST passed, the option ROM checksummed, the adapter ID showed up in the reference-diskette setup. Then I sat down at the IBM PS/2 Model 57 — the 8557, a 386SX desktop — booted it, and the card was simply not there. No adapter, no slot, nothing. POST didn’t even complain; from the chassis’s point of view there was no WonderMCA in the bus at all.

That’s a particular kind of frustrating. A crash gives you a code. A disappearance gives you nothing. The card was clearly alive — the screenpad lit up, Core 0 was running, the UART banner printed — but the one thing it had to do during the first second of POST, answer the POS scan, it wasn’t doing.

What the card is supposed to do

A quick … Read the rest

Uncategorized

DMA / Single player always wins…

/ / Uncategorized

A bet you can’t lose — and somehow did

Micro Channel arbitration is a tournament. Any device that wants the bus — a DMA controller, a bus-master card, the refresh logic — drops its 4‑bit arbitration level onto the shared ARB[3:0] lines during the arbitration window, and the lowest level wins. The lines are open‑collector and active‑low: you pull down the bits that are 0 in your level, you release the bits that are 1, and the wired‑AND of everyone’s drive settles to the winner. Lose a bit to someone with higher priority, and you drop out of all the lower bits too.

Here’s the thing about a tournament with one entrant: the single player always wins. When WonderMCA is the only card asking for the bus, its arbitration is a formality — present level 0001 (DMA channel 1), nobody contests it, the planar grants it the bus, … Read the rest

IBM PS/2

WonderMCA — the new board revision is heading to JLCPCB

/ / IBM PS/2

The next WonderMCA board is on its way — the new revision is currently being manufactured by JLCPCB. This is the biggest step the project has taken so far: it sets out to fix every issue from the initial release while adding a whole stack of new capabilities that push the card much closer to its final form.

What’s new

  • RP2350 design is now using 0603 footprint
  • A bigger brain for the bus — new CPLD. The card moves to the ATF1508-10 in a PLCC84 package, giving plenty more room for the Micro Channel glue logic.
  • In-circuit CPLD programming. A TAG-Connect footprint lets the CPLD be reprogrammed in place — no more fiddling with the chip to push a new logic build.
  • A full 16-bit data path. A new mux plus an additional bidirectional buffer let the card properly handle the 16-bit MCA data bus.
  • More signals on the
… Read the rest
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