BMOW title
Floppy Emu banner

Archive for the 'Floppy Emu' Category

Acrylic Cases Back in Stock

Acrylic cases for the BMOW Floppy Emu and ADB-USB Wombat are back in stock. If you’ve been waiting for one of these, your wait is over. The Floppy Emu cases were held up longer than expected due to international shipping delays, which continue to be a major challenge. The Wombat cases are made locally, but the manufacturer has mostly transitioned to making emergency medical protective equipment and is processing other work slowly. To compound the problem, the first delivery of Wombat cases were somehow mis-cut at 15/16ths the correct size. The whole batch had to be thrown in the trash, and new cases re-cut. Sometimes even the simple things are hard!

Read 3 comments and join the conversation 

Floppy Emu Update: Favorites, Lisa Fixes, and More

New features have arrived for the BMOW Floppy Emu disk emulator! This update has something for everyone.

 
Favorites Menu

If your SD card contains hundreds of disk images or many deeply-nested subdirectories, navigating through the contents of the card can become tedious and slow. For convenience, an optional Favorites menu can now be configured. At startup the Favorites menu will be shown instead of the standard File Explorer menu. If needed, you can exit the Favorites menu at any time in order to choose non-favorite disk images.

The Favorites menu is configured using a plain text file named favdisks.txt. This file should be placed in the top-level root directory of your SD card. In this file, list the path to each favorite floppy disk image, one per line. An example file is included with the Floppy Emu’s firmware update package, which can be downloaded from the BMOW web site.

 
Auto-mounting

The Macintosh and Lisa will wait patiently for you to insert a boot disk, but most Apple II computers will give up if a boot disk isn’t found within a few seconds after power-on. To make life easier, past versions of the Apple II compatible firmware included a simple auto-remount behavior. At power-on, the most recently used disk was automatically re-mounted, if the disk was inserted when the power was turned off last time.

This new firmware enables further control over the Apple II automount behavior, using an optional automount directive on the first line of the favdisks.txt file. This is just the word “automount” followed by a space and a single digit:

  • 0 – Never automount. The Floppy Emu will always power up to display your Favorites menu.
  • 1 – Always automount the first disk image listed in favdisks.txt
  • 2 – Automount the most recently used disk, if there was a disk inserted when the power was turned off last time.

Automounting is only supported for the Apple II floppy disk emulation modes. The automount directive has no effect in other emulation modes, or for Macintosh / Lisa disk emulation.

 
Lisa 2/5 Fixes

Unlike the Lisa 2/10, the Lisa 2/5 doesn’t have an IWM chip for processing floppy disk signals. It uses a collection of discrete logic chips to accomplish the same result. For several years I’ve struggled to understand why the Floppy Emu firmware works poorly with the Lisa 2/5, and now I finally have the answer.

To detect a “1” bit from the floppy drive, the computer looks for a high-to-low transition occurring somewhere in the 2 microsecond bit window. It repeatedly samples the signal during that 2 microsecond window, looking for a transition. It turns out that the IWM samples the signal at a higher rate than the Lisa 2/5 discrete logic. The high periods of Floppy Emu’s “1” bits were too short to be reliably detected by the Lisa 2/5 level-sensitive hardware. This firmware update doubles the width of the high period, and my Lisa 2/5 testers report that it’s now working smoothly.

 
Floppy Emu for Visually Impaired Users

Several small tweaks have been made to improve the experience for visually impaired users. A new appendix has also been added to the instruction manual, with a detailed description of the behaviors necessary to use the Floppy Emu without seeing the display. The favorites menu was initially developed as a tool for blind users, before being extended into a general-use feature. With the Favorites menu, any desired disk image can be chosen reliably by counting how many times you’ve pressed NEXT before pressing SELECT to insert the disk.

Today’s firmware update also introduces an optional emumode.txt config file, which simplifies the process of changing the emulation mode by reducing the number of button presses needed. If this file is present, then as soon as the emulation mode menu is opened, the Floppy Emu will automatically change the emulation mode according to the ID specified in the file. An example file is included with the Floppy Emu’s firmware update package.

 
Download the New Firmware

Mac/Lisa firmware: mac-lisa-0.8G-F15
Apple II firmware for Floppy Emu Model B and C: apple-II-0.2L-F25

Read 6 comments and join the conversation 

Floppy Emu SoftSP Warning

I’m calling attention to a hardware issue with the third-party “softSP” card that can damage your Floppy Emu when the two are used with a Disk II controller card in an Apple II+ or Apple IIe. This issue creates a power-to-ground short circuit that will cause accumulating damage to the transistor structures on Floppy Emu’s interface chip. The symptoms don’t appear immediately, and it may seem that everything’s OK for days or weeks, until the Floppy Emu begins to fail irreversibly. The good news is that a simple cable modification is all that’s needed to use softSP and Floppy Emu together safely.

 
softSP Pseudo-Smartport

BMOW isn’t affiliated with the softSP card – it’s sold by a third party and is designed for use with another type of disk emulation product. It does appear to work with the Floppy Emu initially, and in recent months the Total Replay game collection has inspired a few people into using softSP with the Floppy Emu. Some popular YouTube videos even specifically recommend this combination, even though softSP isn’t designed for use with the Floppy Emu.

The problem is that softSP provides a software patch for Apple II disk controller functions, but does nothing to address the resulting low-level electrical problems on the disk interface. The softSP card contains a small ROM that overrides the built-in ROM on a standard Disk II controller card. It essentially reprograms the Disk II card, so instead of functioning as a 5.25 inch floppy disk controller, it now functions like a Smartport disk controller, which supports block-based disk I/O for disk sizes up to 32 MB. Neat! But there’s a catch.

You can’t safely connect a Smartport device to a Disk II controller card, no matter how the card’s internal logic might be modified. That includes Floppy Emu when it’s configured in Smartport emulation mode. The reason is that Smartport devices connect pin 12 internally to ground. This is how other connected equipment and daisy-chained drives know that they’re Smartport drives, and it’s essential for correct daisy-chain operation of Smartport drives with the BMOW Daisy Chainer or the Apple Unidisk 3.5 drive. For other types of Apple II disks as well as the Macintosh and Lisa, pin 12 is used for the SELECT signal. But on the Disk II controller card, pin 12 is connected to the +5 volt power supply. So when you connect a Smartport device to a Disk II controller, you create a direct power-to-ground short circuit. Ouch!

To be clear, there’s no specific hardware problem with the softSP card itself – it’s just a ROM. The problem arises when using the softSP card to reprogram a Disk II controller card, which is then connected to a Floppy Emu that’s configured in Smartport emulation mode.

 
Accumulating Chip Damage

The Floppy Emu board has a small inline protection resistor that will prevent immediate damage and failure due to this short circuit, but it’s only meant to protect against brief transients during power-up and power-down, or brief accidental mis-configuration. The Floppy Emu’s CPLD interface chip will likely not survive sustained operation in this mode, because it will cause a continuous current on pin 12 due to the short circuit, with a current level that’s more than twice the absolute maximum rating of the chip. This can eventually cause damage to the chip that will appear as intermittent disk errors or total failure of the device. Unfortunately this type of damage is cumulative, so even if you stop using Smartport mode with softSP and a Disk II card, the damage is already done.

With the continuous over-current, the insulating silicon layers between parts of a transistor can wear away, or develop small holes. At first the effect is minor – maybe the leakage current is more than it should be, or the noise margins are reduced below the spec. The chip may still work OK under normal conditions, but problems may appear under extraordinary conditions at high/low temperatures, or when the supply or signal voltages are close to the rated margins, or when substantial EM noise or voltage transients are present. A problem might cause a 0 to become a 1 somewhere, resulting in a visible I/O error, or it might cause the whole chip to stop functioning until power is turned off. As chip wear grows worse, you may start to see these kinds of problems during ordinary usage. Eventually the problems will grow so frequent that the chip is no longer really usable, or the wear will progress all the way to an internal short-circuit or open circuit within the chip itself, effectively destroying it.

This kind of chip damage can be viewed as a type of gradual wear, like wearing down the engine in your car, rather than a simple yes/no question of is it damaged or not-damaged. Even normal use causes chip wear, and chips do have finite lifetimes, but normally the lifetime is measured in decades or longer. In this case the power-to-ground short circuit is like driving your car without enough oil in the engine. It’ll work for a while, but you’ll start to notice it’s running increasingly rough, and maybe it’ll develop occasional trouble with stalls or failure to start. Then one day the engine will completely seize up and the car will no longer run at all.

 
Cable Modification Fix

A simple work-around is to sever the 12th wire of the 20-conductor ribbon cable. The red wire is number 1, so simply count wires from there and cut number 12 using a small nail or a razor blade. The resulting cable will work for softSP Smartport emulation with a Disk II controller card, without creating a power-to-ground short circuit. It will also work for standard Apple II 5.25 inch floppy disk emulation. But the modified cable won’t work for true Smartport emulation with other Smartport hardware, nor for 3.5 inch floppy disk emulation, nor for Macintosh or Lisa disk emulation. If you don’t want to modify your original ribbon cable, you can get a spare cable from DigiKey for a few dollars.

Unfortunately modifying the cable won’t undo any damage that’s already been done, so if you plan to use softSP with your Floppy Emu, you’ll need to make this cable modification right from the start. Be safe!

Read 9 comments and join the conversation 

Floppy Emu and Disk Daisy Chainer Restock

After a few weeks’ absence, the BMOW Floppy Emu disk emulator for vintage Apple computers is back in stock. Get yours now at the BMOW store. This is the latest version Floppy Emu Model C, with OLED display.

Floppy Emu is a floppy and hard disk emulator for classic Apple II, Macintosh, and Lisa computers. It uses an SD memory card and custom hardware to mimic an Apple floppy disk and drive, or an Apple hard drive. The Emu behaves exactly like a real disk drive, requiring no special software or drivers.

 
Disk Daisy Chainer

The Daisy Chainer adapter for Floppy Emu is now available for public sale, after a long period of limited release. The Daisy Chainer board makes it possible to insert a Floppy Emu anywhere into your daisy chain of Apple II drives, with other floppy drives before and/or after it in the chain. It provides a nice improvement in flexibility for Apple IIGS owners and other Apple II users with complex drive setups.

The Daisy Chainer is a smart device with an onboard microcontroller for decoding the drive enable signals. It automatically senses the type of disk drive connected to its downstream daisy chain port, as well as the current emulation mode of the connected Floppy Emu. Some past blog posts about Daisy Chainer development are available here: part 7, part 6, part 5,
part 4, part 3, part 2, and part 1.

Be the first to comment! 

Introducing Noisy Disk

Do you miss the iconic sounds of mechanical click-clacking from original Apple II floppy drives? Does the familiar rattling of a boot floppy bring a smile to your face? Today I’m introducing a new product called Noisy Disk. This board uses a mechanical relay to create authentic-sounding disk head movements for the BMOW Floppy Emu disk emulator. Sure it’s useless, but it’s useless fun.

The Noisy Disk board attaches inline with your existing Floppy Emu cable, using the provided 6-inch extension cable. When Floppy Emu is configured to emulate a 5.25 inch Apple II floppy drive, the Noisy Disk onboard relay snaps open and shut whenever the emulated disk steps from one track to the next. It creates a symphony of disk noise that will bring back memories of 1979.

Noisy Disk is compatible with Apple II family computers while using Floppy Emu in 5.25 inch emulation mode. Nothing will be harmed if Noisy Disk is used with other computers or emulation modes, but you’ll hear strange clacking noises that don’t match the disk activity. It’s recommended to use Noisy Disk in 5.25 inch emulation mode only.

The product includes the Noisy Disk board with 2 x 10 pin rectangular input and output connectors, and a 6-inch extension cable for connecting to your Floppy Emu board.

Noisy Disk is available now at the BMOW Store.

Read 6 comments and join the conversation 

Seeking Daisy Chainer Early Adopters

If you’ve been waiting for a Daisy Chainer for your BMOW Floppy Emu disk emulator, I’m happy to report that it’s ready to go. The Daisy Chainer board makes it possible to insert a Floppy Emu anywhere into your daisy chain of Apple II drives, with other floppy drives before and/or after it in the chain. It provides a nice improvement in flexibility for Apple IIGS owners and other Apple II users with complex drive setups.

I have a couple of hand-assembled Daisy Chainers available for sale now, and I’m seeking a few early adopters who have time to exercise it this week with their computer and drives. I need to make sure these first units get into the hands of people who can try them ASAP and confirm compatibility with their equipment, before I move ahead with manufacturing more. If you’ve got the time and the desire, send me a note!

Read 15 comments and join the conversation 

Older Posts »