RETRO Innovations

Archive for April, 2011

uIEC/SD Daughtercard modifications

by on Apr.27, 2011, under Hardware Design

uIEC/SD 3.1 Daughtercard Rev2

uIEC/SD 3.1 Daughtercard Rev2

After completing the first revision of the uIEC/SD daughtercard, I grew unsatisfied with with the sole but significant shortcoming.  In all applications except the C128DCR usage, the dual IEC connectors would obscure some important port of the host machine.  On the VIC/C64/C64C, the connectors would prevent user port usage, while C128/C128D applications would affect video and IEC connector usage.  With so many machine types affected, there was little reason to include a cassette port connector, since many of the uses would require a USB power supply.

Removing the cassette port connector would create two issues:

  1. The unit would cost more to produce and sell (mandatory USB power supply).
  2. Complexity would be increased (additional power supply to attach, additional power connection required, additional item to remember when packing unit for travel).

When considering placement options today, I happened upon a nonstandard placement idea that appears to resolve the shortcoming without undue implications.

Since it was important to retain the cassette port connector, this meant IEC jack placement must be directly opposite the cassette port jack.  Any other option exhibits the initial issue.  However, that left no location for the actual uIEC/SD unit itself.  I realized I could orient the drive into a vertical position.  Not only does this cleanly resolve the placement issue, this also removes a long standing shortcoming of the previous design.  Previously, inserting or removing a card meant holding onto the entire unit so it would not push away from the user. In the new orientation, insertion and removal will require one hand.

The vertical orientation now means VIC-20, C64, C64C, and C128 users can see the top of the unit while looking at their machine.  Card access is much easier.

The sole downside: With the unit now perpendicular to the daughtercard plane, enclosure mounting will pose additional challenges.  However, I’m much happier with this design over the previous revision:

  • IEC ports no longer restrict access to C128, C128D, VIC-20,C64, or C64C owners.
  • Many owners never enclose the unit.  The new revision puts the unit behind the machine and physically attaches the unit to the machine, minimizing the need for an enclosure.
  • The few that do mount in an enclosure appear savvy enough to construct an extension for the uIEC/SD connector or determine an alternate connection method.

I appreciate comments and thoughts on this new design.  Namely, how do people feel about a vertical drive configuration?

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uIEC/SD Daughterboard Redesign

by on Apr.26, 2011, under Hardware Design

uIEC/SD Connector v3.1

uIEC/SD Daughterboard v3.1

With the next batch of uIEC/SD units, I found both financial and feature-enhancement reasons to redesign the connector daughterboard.

Compared to the earlier daughtercard option, there are some key advantages to the new unit:

  • Dual IEC connectors.  No longer much the uIEC/SD be the last unit in the IEC bus chain.
  • Onboard RESET button
  • Via jumper, Machine reset can optional reset uIEC/SD.
  • Better function button access
  • Solder pads for all major functions (buttons, PWR, GND)
  • No more pigtail power connector
  • Mini-USB power supply support

The only downside to the new design is the IEC port placement.  On the C64/C64C, the IEC ports will interfere with the user port, while they will interfere with IEC and Video ports on the C128/C128D.  The C128DCR seems to be least affected.  Thus, I am still debating design elements.  Comments/Thoughts are greatly appreciated.

Why the change now?

  • Significant savings can be realized by utilizing a new IEC jack footprint.
  • I am running low on C2NPower PCBs (used for the pigtail) and resupply is not cost effective at present.
  • Wiring pigtails takes time, which in turn slows down order fulfillment.
  • Some people object to the power pigtail approach.

 

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X-Pander3, VIC-20 Edition

by on Apr.14, 2011, under Hardware Design

XPander3 VIC PCB

XPander3 VIC PCB

After a lengthy wait, I am finally finishing the VIC version of the X-Pander3 cartridge expansion system.  The design is subject to some more changes, but I am starting to source the required cartridge port connectors needed for the design.

The unit shares design elements from the C64 version, but provides maximum flexibility for the VIC-20 owner:

  • I/O2 and I/O3 are swappable
  • All BLK and RAM signals can be switched
  • As with the C64 version, Slot 3 can be vertical or horizontal
  • Standoffs to align board with height of expansion port
  • All controls are located on right side for ease of access
  • The ubiquitous “RESET” switch!

The unit will likely retail for a bit more than the C64 version, mainly due to the additional components and the larger (7.5″x5.0″) PCB size.

Astute viewers will notice an unused switch on each bank.  I invite suggestions for use.

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