RETRO Innovations

Mini 1541

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.

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

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)

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.

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.

uIEC/SD 3.2 PCB Design

My plan to ship uIEC/SD units by end of June was evidently overly optimistic.  It took longer than expected to modify the uIEC/SD PCB design, and the design had to be checked more thoroughly since I will not have time to assemble and test a sample before ordering the SMT stencil (a metal “mask” laid over the PCB that is used to force solder paste to only deposit on the exposed PCB pads)  and a production PCB run.  Thus, I am crossing my fingers that the redesign is correct.  The new design looks very similar to the older, though I have designed the PCB to fit a small Hammond 1551 enclosure (the 2 half-present holes on the corners of the board).

At this point, I’ve moved the expected ship date to July 12, and alerted customers about the delay.

SD Card Socket

Though I tried for weeks to source a few more of the connectors used on the current uIEC/SD design, the effort proved fruitless.  In parallel, I started asking suppliers for other options.  As the hope for more old stock dwindled, I decided to source a new connector.  I selected a connector that is both less expensive than the older option and can be sourced from multiple companies.  This should alleviate my dependence on a single supplier for such a critical component.

I also purchased a stock of Micro SD sockets.  The price was right, and I think it’s time I designed something using uSD.

Of course, this decision implies I have to finish the new uIEC/SD board design, spin a new board, and create a new surface mount stencil.  Still, the total cost compares favorably to buying old stock SD connectors, even if they were available.

I guess I should feel lucky I have been immune to the issue until now, but I have just received word that the newest batch of uIEC/SD units is stalled.  The SD connector has been discontinued from 3M, and though I successfully ordered a final reel of them for this production run, the supplier evidently over-committed the remaining units.  I’ve spent the last few days attempting to source a comparable option, to no avail.  Seeing no other options, I will have to redesign the board to accommodate another SD connector, which means the 200 existing PCBs are now official useless, I’ll need to order a new surface mount stencil (used to apply the solder paste to the PCB before parts are laid onto the board), and the pre-ordered units will be delayed beyond May 31.

It does cause me to wonder why 3M decided to discontinue the offering.  It was a economical and very robust connector, so I can’t imagine it was little-used.  In any case, it’s no longer available, and I’m left to find a suitable replacement and notify customers of the additional delay.

uIEC Daughtercard v3.1

After I’ve worked on a project for a suitable amount of time, it’s important to let it sit for a few days to allow the design to “mature”, so to speak.  Sometimes, nothing changes, but other times, you come up with a great idea that solves lingering concerns with the existing design.

With the uIEC/SD daughtercard design “n the shelf”, an email exchange with customer Ken Page caused me to rethink parts placement.  I was unsatisfied with the vertical arrangement of the uIEC/SD main board in the v2 design, but could find no other way to mount the board.  However, during the conversation, I came upon the idea of moving the IEC connectors to the bottom of the board.  That solved two problems.  One, the board needs “standoffs” when plugged into the VIC/64/128 cassette port, or else the board will flex when buttons are pushed or SD cards are inserted.  Bottom mounted IEC connectors provide the required height positioning.  With them mounted under the unit, I can now offer a horizontal mounting option.  In addition, I was able to add 2 more connection pinouts.  This means that one can use the daughtercard as a miniature “backplane”, attaching up to 3 uIEC/SD units to a single daughtercard.

I also took the opportunity to put a 7805 voltage regulator pinout on the board and a “barrel plug” wall power adapter option.  I do not intend to populate those items, but customers can easily add them.

I realized that no amount of restructuring this design will appeal to everyone.  Some people want the smaller board with the single IEC connector.  So, I decided to offer both options.  The older design is harder the manufacture, so I will price accordingly.

uIEC Daughterboard v3.1

Due to some changes in the PCB houses my assembler uses, and cost issues with the DIN6 connector for the uIEC/SD daughtercard, it’s actually cheaper to create a new PCB design than to use the old one.  To that end, I have slightly modified the design to include a power supply connector and a switch to disable the RESET line (in case you wanted the device to stay in a subdirectory across reboots of the computer).  To stay on delivery targets, I need to send this off to the assembly house this week, but I am interested in comments on the changes and any others that might be possible.  Before people ask, I attempted to add a second IEC connector, but then the IEC connectors must be positions to face the side, and the board ends up larger than the uIEC/SD itself.

Ingo Korb has released a minor update to sd2iec (used in uIEC, among other solutions). Users are encouraged to update to this release.  Fixes/Features include:

• U1/2, B-R/W commands now work without a trailing CR character (reported by Draco)
• UI now always reports the dos version no matter what characters are following unless it’s a + or -. Previously anything but ±/nothing would result in a SYNTAX ERROR which doesn’t match what a 1541 would do. (reported by skoe)
• JiffyDOS timing optimized, now loads a massive 1.8% faster!