EasyFlash 3 Now In Production

EasyFlash3 PCB
EasyFlash3 PCB

It’s taken longer than anticipated, but EasyFlash 3 production is finally underway.  The first 200 boards are in production, with delivery scheduled for late March.  The storefront is open for pre-orders, with pricing set at:

  • EF3 without enclosure: $59.99
  • EF3 with enclosure: $64.99

I delayed production slightly to lengthen the prototype PCB so that switches could be placed at the rear of the cartridge, and the delay allowed the design to incorporate last minute design enhancements.  However, I will admit I treaded lightly on this production, as it’s a reasonably complex unit and RETRO Innovations is not the principal designer.

I realize late March is still significantly far in the future.  If you want a unit now, please check out Retro Donald’s storefront, which has uncased units in stock.


C=Key now Shipping

C=Key (PC KB to C64 configuration)
C=Key (PC KB to C64 configuration)

By popular demand, we’re now offering both kit and assembled versions of our C=Key Commodore Keyboard Dual Mode Interface.  This unit supports using a PS/2 keyboard to a VIC-20,C64,C64C,C128,C128D,C128DCR, or SX64 machine in one configuration.  It can also interface keyboards for those same machines to a PS/2-based PC (or USB PC via a PS/2 to USB adapter).   We’ve held off for years in offering this product, because PS/2 keyboards are getting scarce and we are redesigning the unit to work with USB keyboards.  That said, numerous enthusiasts convinced us there is enough interest to offer the product in the store.  Unlike our other offerings, we’re still considering this a “project” rather than a complete product offering.  If you are a tinkerer who doesn’t mind getting his/her hands dirty with microcontrollers, this might be of interest.  However, if you’re a fan of plug and play and easy upgrades, we encourage you to wait until a USB version is available.

EasyFlash 3 Introduction

EasyFlash 3 Prototype
EasyFlash 3 Prototype

In late 2010, a group of folks suggested the need for a KERNAL replacement cartridge.  This cartridge would allow those with socketed KERNAL ROMs to enjoy KERNAL upgrades like JiffyDOS and would also help KERNAL developers try out new ideas before committing them to EPROM.  Due to the complexity of “replacing” a ROM inside a machine without physically removing it, a Commodore Bounty was created to encourage someone to develop the solution.  Thomas Giesel took up the challenge, finding a novel solution to the complexity, and developing an economically viable solution.  Along the way, Thomas merged in some additional features, and the result is EasyFlash 3.

EasyFlash 3 offers a number of features:

  • 8 8kB slots for alternative KERNAL ROM images,
  • 7 EasyFlash I cartridge image slots.
  • Support for the following cartridge formats
  • Normal 8k
  • Normal 16k
  • Ultimax
  • Ocean Type 1
  • EasyFlash
  • EasyFlash xbank
  • USB support (for transfer of data to/from PC/Mac/Linux
  • Field upgradeable firmware and hardware configuration
  • Ability to replace/add/remove images from the C64

EasyFlash will soon be available from RETRO Innovations and can be used on the C64, C64C, and SX64.  C128/C128D use is not currently supported.


X Pander-3 VIC Released to Production


The X Pander-3 VIC brings the ultimate in cartridge port expansion options to the Commodore VIC-20.  The unit features 3 independently switched vertical ports and a companion horizontal port.  Power, both I/O select lines, and all BLK and RAM select lines can be individually switched on or off, while the I/O select lines can be swapped on the second and third/fourth expansion slot.  Units should be available for sale starting mid-January.

23XX Adapter In Limited Production

23XX Adapter PCB
23XX Adapter PCB

Assuming it’s not obvious, let me assure readers that not all design ideas are original. In fact, RETRO Innovations welcomes customer-inspired products.  Let me relate the story of one such idea.

The initial 2364 adapter design was trivial and joins the myriad of similar designs available online.  Though it was an original design effort, I did check the design with existing online  versions.  Still, there is nothing particularly innovative about it.

The design, though, does assume the 2364 pinout is invariant, which turns out to not be correct.  Not only can the 2364 appear in 28 pin variants, but even the 24 pin variant found on Commodore machines can occur in two different configurations.  The more common variant sports a active low “select” line, while another version flips that to active high.

A customer discovered this alternate variant after purchasing an adapter.  Ever the resourceful one, he wired an inverter onto the select line for correct operation but suggested a new product variant for other custmers.

Initially, I took the idea and implemented it by making the “select” line configurable.  It’s a common trick to use an XOR gate to invert the state of a data line.  Still, the resulting design felt lacking.

Along the way, another customer suggested a 2332 Adapter, which uses the same 24 pin footprint as the 2364, but can arrive in 4 configurations (2 select lines).  Datasheets for the 2332 also showed the 2316, which supports 8 configurations via 3 select lines.  Since these are less common ROMs, they don’t get much attention in the retro market.  Nonetheless, I determined that a bit of rework would allow one adapter to support any variant of 2316 or 2332, and any 24 pin 2364 variant.  As the revised 2364 design required a TTL IC for signal inversion (74HCT86 XOR gate), rework required finding a TTL IC that could optionally invert and combine up to 3 select lines.

As the picture suggests, the 74HCT138 supports the required function, and it often costs less than the ’86, making it a perfect choice.  The cost, of course, if the need to “configure” the unit for a specific use.  Solder pads must be connected according to a truth table to support a particular device.  Yet, the adapter can be a time saver for those who need to quick swap out a dodgy 2316/32/64 with a known good EPROM with correct code.

Though this unit can be configured to support the common case (and can be soldered up without the TTL IC in this configuration), the regular 2364 Adapter supports the majority of common uses, so we’ll still offer the original design alongside this one.


ZoomFloppy Tape Support

Arnd Menge has delivered the first set of patches allowing ZoomFloppy to interface with 1530/1531 tape hardware.  In the coming days, Arnd hopes to complete development of this new feature, and I am looking into creating a daughtercard that will attach to the ZoomFloppy via the X5 expansion connector.

Obviously, such support is alpha at present, but the device is proving very versatile with the recent improvements!

Arnd Menge

uIEC/SD 3.2 vs uIEC/SD 3.1

uIEC/SD 3.2 versus 3.1
uIEC/SD 3.2 versus 3.1

Even though there’s not much to tell, some folks asked about the differences in the new v3.2 uIEC/SD design.  A picture is worth its weight in gold here, but I’ll also point out some less apparent details.

  • Due to the new SD socket footprint, I was able to push the edge of the socket further from the edge of the board.  This should help with implementations sitting behind thick plastic cases.
  • Two small half moons (on the top left and bottom right) should allow the unit to be mounted in a Hammond 1551RBK enclosure.
  • Although not populated on the PCB, there are pads for a Dallas DS1307 (or compatible) RTC with battery backup.  The battery pins are shown on the right of the new PCB, while you can make out the watch crystal footprint below them on the right side.
  • The LEDs have been pushed further outside the PCB.  Truly, the assembly house went overboard on the first batch, but they should stick out to the edge of the SD socket.

Nothing else, I am afraid.  I tried to add device jumpers to the design, but ran out of space and time to route the pads.  The rest remains the sames, including:

  • Pinout.  v3.2 shares the same pinout as v3.1 and v3.0
  • Mounting location.  The mounting holes are in exactly the same place.  Though the SD socket has mover 1/8″ further out, the PCB will fit in exactly the same place as previous designs.
  • Same uC.  The Atmel ATMEGA1281 is still in use, as is the 74LVC06  serial bus driver


How Low Can You Go?

Advanced Interconnect Header
Advanced Interconnect Header

Designing “piggyback” PCBs can prove challenging at times.  For example, extending a piggyback PCB outside of the original ICs footprint must contend with physical obstructions (connectors beside the IC, passives like capacitors or resistors sticking out of the original PCB, etc.).  Luckily, it’s often easy to print out a 1:1 version of the design on paper, cut to dimensions, and test fit onto the original board.  Often, obstructions can be mitigated by switching to SMT components and using a smaller footprint or changing the PCB outline to for around obstacles.

However, less easy to design around are height issues. The best approach involves replacing the original ICs function entirely.  Replacement solutions like ROM-el rise little further than the original IC they replace.  If the original IC is still needed, but a pass-through of all signals to the original IC is acceptable, the design can utilize a socket both to contain the original IC, and let the pins from the socket function as the header for the piggyback PCB connector to the original socket.  This solution typically rises a bit further, but rarely far enough to cause issues.

Designing a piggyback PCB that requires the original IC and must reroute some of the original IC signals forms the worst case.  If the original IC height is defined as ‘X’, and we ignore the .8mm to 1.6mm of the PCB, this design still requires a header (‘X’ height), a socket for the original IC (‘X’ height), and the original IC (‘X’ height).

Mind you, most 70’s and 80’s systems designs left lots of room between board or above the original PCB.  Thus, 3X height, while potentially looking out of place, will often continue to work.  However, as designs became more compact, such luxuries are often unavailable.

The Commodore 1541II disk drive PCB is one such example of the last case.  Commodore, in order to reduce overall drive height as much as possible, left little room between the control PCB and the drive mechanism mounted immediately above it.  Designing a piggyback board for use in this device is particularly challenging, as there is simply no way to add any height; the drive mechanism won’t rotate the disk if the piggyback board touches it, and you simply cannot relocate the mechanism.

Months ago, I pulled a CMD JiffyDOS ROM out of a 1541II, and was surprised to see an unusual header being used to minimize height.  Instead of a normal header, which is simply a batch of double ended pins stuck in a plastic socket, this header used a thin flexible “film” to hold the pins in place, adding no height at all.  I had no idea of the source, but a quick request on the CBM Hackers mailing list yielded a source.  Vanessa Ezekowitz tracked down the manufacturer (Advanced Interconnections) and the product (Peel-a-Way Removable Carriers).

Of course, this doesn’t solve every problem, but it does offer new hope for designs in height constrained locations.  The solution is not cheap (10X the price of a normal IC header), but it can turn an impossible design into a possible product.


uIEC/SD v3.2 Shipping

uIEC/SD Daughtercard v3
uIEC/SD Daughtercard v3

As of tonight, the last of the uIEC/SD pre-orders have finally shipped.  In fact, for the first time since early May, we are caught up on order fulfillment.  Now, I can relate some features of the new uIEC/SD daughtercard option:

  • Two (2) IEC connectors.  No need to ensure the uIEC is the last item on the bus
  • 3 uIEC/SD connectors (one populated by default).  One is designed to point backwards from the daughtercard (for a horizontal setup), while the other two are vertical.  (This means users can reposition the unit for ease of use, or can utilize more than 1 uIEC on the same daughtercard)
  • Integrated power plug.  No more pigtail wire to break.
  • RESET button on board.
  • Selectable uIEC/SD RESET operation.  Removing the on-board jumper will prevent computer resets from affecting uIEC/SD unit.

    uIEC/SD Daughtercard v3 (side view)
    uIEC/SD Daughtercard v3 (side view)


Of course, the original Daughtercard remains available for those who prefer a minimal approach.  The original daughtercard works best for C128D/DCR users, while the new unit works best for other machines.

The new unit will be available as an option in the store shortly.


Finally! uIEC/SD Units Shipping from Manufacturer

uIEC/SD 3.2 Production Unit
uIEC/SD 3.2 Production Unit

After what seems like an eternity, the first 50 uIEC/SD units have been shipped from the assembly house.  Exhibiting the longest design/manufacturing cycle I’ve ever witnessed, they’ve been unavailable since late April, 2011.

For those new to the saga, the normal stock re-order process in early May ran aground when the specified SD socket was unavailable for purchase.  Though the socket had been discontinued (and the manufacturer did send me an email), the sales distributor showed (and allowed me to order) a last batch of units.  I had no idea the distributor would be overcommitted and call notifying me they could not fulfill the order.  That call set off a multi-week effort to find alternate stock, which then morphed into finding another option that fit the footprint, and finally resulted in redesigning the board to accommodate a new SD socket option.  That delay ate up the entire month of May and part of June.

Things started getting interesting in late June, as I awaited new stock.  First, the date slipped, which was not altogether surprising (it was but an estimate at best).  Then, the assembly house sent word the DIN6 IEC connectors would not fit in the daughtercard footprint.  This was not a showstopper, as I had sourced connectors for another project that would work.  A while later, the assembly house IMed on a Thursday night that the new SD connector would not fit the design.  I double-checked the PCB design and measured the sample units.  Everything looked correct.  I asked for a picture to view the issue. They promised one later that day.  But, they are a half day ahead.  I received it the end of their day, Friday morning here in the US.  By that time, they had gone home for the weekend.  Looking at the picture, I immediately solved the problem.  They were trying to solder the old SD socket onto the new PCB design.  Still, that wasted time.

Luckily, after nearly suffering heart stoppage over the SD socket issue, the rest of assembly went relatively smoothly.  Complicating the shipment: most pre-orders specified a daughtercard option.  Thus, both items required assembly before any orders could be filled.  As well, I produced the new daughtercard design in this order.

Now, to see if my design skills are good enough to overcome the lack of prototype assembly and testing.