Both complete and kit-based PS/2 Encoder units are now shipping in the RETRO Innovations store. We made some last minute firmware enhancements, and are shipping with an upgraded microcontroller, the Atmel ATMEGA168 (16kB of FLASH ROM, the current firmware needs only ~4kB).
The web site will shortly be updated with pinouts and configuration notes. Stay tuned!
Looking for 12/24 .156″ edge connectors for your Commodore user port project or a IEEE interface that will connect to the PET/CBM computer IEEE port? RETRO Innovations has sourced 2,000 units with pins that can be installed in a PCB or soldered to the edge of a PCB. These connectors do not have the mounting ears, to allow maximum flexibility for fit. They are in the store for purchase now!
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.
Just a quick note that I’ve received the first batch of PS2Encoder PCBs and have placed them in the store. Assembled units might take a few weeks, but kits should be available in a week, and PCBs are available now. The firmware might yet have a bug or two, so I encourage initial buyers to be somewhat technically savvy, in case reprogramming is needed.
Rik Magers managed to stuff a uIEC into a tiny little enclosure that looks like a miniature CBM 1541 case. More details are available at his blog.
As usual, ECCC 2011 was both hectic and fun. It’s been a few days since the show, as it took a while to travel home and recover.
RETRO Innovations arrived Friday evening in time to unload equipment into the show hall and select a couple choice tables near power and good traffic areas. However, almost as soon as we finished, it was time to close the hall for the night. I gathered up a few items and set up in the Fairfield Hotel foyer to finish some soldering and check on email. When I left at 1AM (early, I know), the room was still full of Commodore folks.
Saturday started strong, with sales brisk until nearly noon. ZoomFloppies sold well, though uIEC/SD unit sales were nontrivial as well (typically, a large number of the same folks attend each year, so year over years sales of the same item tend to decrease after the first year). JiffyDOS ROM sets sold at a steady pace, as did IEC cables. By mid afternoon, sales had tapered off and I was able to present ZoomFLoppy at 4PM in the demo area without too much trouble. I drug in an 8050 drive to show off IEEE support, recently added to the ZF firmware, while showing the rest of the ZoomFloppy features.
In the evening, I worked with Leif Bloomquist on a long-in-development VIC-MIDI project. Having first collaborated with Leif on the project in early 2010, it’s been a long road getting to this point. But, Leif worked on the driver code in the evening and was able to coax correct operation out the circuit before nightfall. Hopefully, a finished design and a product offering will be available before the first show in 2012.
After the hall closed Saturday night, we once again gathered in the hotel foyer. I sat with Six and Elwix of Style to discuss some new hardware design ideas, but mainly just enjoyed the din of activity.
This year, the show opened again on Sunday, though I had already made alternate Sunday plans. Though I was in no hurry, packing went slower than expected since I had to pull items out a number of times to make last minute sales. I can’t complain about sales, though. By 1PM, I had stuffed everything back into containers and closed up shop.
Of course, no show would be complete unless purchases were made. While eyeing some individual 8″ floppy disks, I happened upon a VIC-1540 with an original DOS ROM. Those ended up in my possession (I already have a 1540, but I don’t have an original ROM). Anticipating purchases, I had left a bit of room for things like this and the 10 VIC expansion cases (Think VIC-1020, but minus the expansion PCB. They were used to lock down the VIC in an education setting) Leif brought to the show (I purchased them at WoC 2010, but was not in attendance). As well, I asked Six (Oliver Viebrooks) to bring an SX64 shipping box to that show I had stashed at his home years before. Finally, the shipping box would make it home.
Or not… At the end of the show, I ended up purchasing a Xerox Phaser 8400 Workgroup color printer (I’ve been looking for a color unit for invoice printing, but couldn’t justify the cost of a new color laser in lieu of the perfectly functioning LaserJet 5 currently in use). The price was too good to pass up, but the cargo area could not hold the printer, the products, the VIC cases, and the SX64 shipping box in addition to suitcases. So, the SX box went home to downstate IL with family. Maybe one day it’ll make it home. It’s been in IL, then in KY, and now somewhere else in IL.
To be truthful, I attend to see folks and share stories, not sell products. It was nice to catch up with folks from past events as well as meet people I’ve only known online. Still, it is nice to sell enough stuff to finance the trip.
Above all, I’m exceedingly grateful that Jason Compton underwrites the entire cost of the event, offering it for free to businesses and attendees alike. May it continue to be held for years to come. I’m also excited that the Vintage Computer Festival was held at the same time in the same building. Though I didn’t get to spend much time at their exhibits, the exhibits were well planned and very intriguing.
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
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.
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:
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.
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:
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.