QBone The only commercially-produced PDP-11 add-in card of 2021. (We think.)

<figure class="align-center"><img alt="An advertisement for the QBone Dual. The card is displayed with a glass of champagne and a single red rose. The headline reads: &quot;A new year. A new DEC romance.&quot; Callouts point to: Eight user-addressable status LEDs, 10/100 Ethernet RJ45, Custom designed handled, Two Qwiic/StemmaQT interfaces, Redesigned construction to DEC specs for reliability and easier installation, and Two warm-swappable Q-Bus driver modules. The copy reads: At DECromancer, we love DEC as much as you do. Our redesigned QBone Dual adds not just memory, hard drive, and floppy disk emulation to your Q-Bus based PDP-11 or VAX; it's got future-proof peripherals like USB and Qwiic I2C expansion -- and soon, Ethernet. QBone Dual is ready to order, so start a new DEC romance in 2025. A footnote reads: With new software downloadable later this year. Circle no. 69 on reader service card. The bottom shows the company logo and website, decromancer.ca." class="image imgcenter" src="https://decromancer.ca/images/qbone-dual-ad-2025-02-14.png"/></figure><p> </p> <p>When we ran out of QBones earlier this year, I groaned loudly. I knew it was time to revisit the complaints we'd received from customers since we first started making them in 2021:</p> <ul class="simple"> <li><p><em>"The board is too tall with the Beaglebone installed, and runs into cards both above and below it."</em></p></li> <li><p><em>"I'd like to use my peripherals with the</em> QBone. <em>"</em></p></li> <li><p><em>"It's too wide for my dual-width</em> QBUS <em>backplane."</em></p></li> <li><p><em>"I keep losing the jumpers."</em></p></li> <li><p><em>"I can't find driver chips anymore."</em></p></li> </ul> <p>That last one is me, actually. Our supply of chips and spares exhausted at the same time as when the last board went out the door. Without drivers, we weren't going to be selling any more QBones.</p> <p>In 2008 Eric Smith did <a class="reference external" href="http://www.brouhaha.com/~eric/retrocomputing/dec/interfacing/chips.html">an analysis</a> of alternative driver chips, and concluded the TI AM26S10 and SN75138 would be acceptable (if not perfect) replacements for the long-since obsolete DS8641 and DS3662 parts. Sadly both parts <a class="reference external" href="https://mm.digikey.com/Volume0/opasdata/d220001/medias/docus/5349/PCN20230516001.3.pdf">went EOL</a> when TI decided to shut down their 150mm wafer process. (This also killed off many of their popular older RS485 parts, such as MC3486/MC3487.)</p> <p>So despite Jörg (<em>aka</em> Joerg) Hoppe's respin of the board in 2024, it was too little too late; the last-time buy window was closed, and stock at most resellers was gone or was restricted in volume to select (read: US Governmental) purchasers only. (We tried.)</p> <p>Things were looking bleak until we got lucky in Shenzhen. A retailer was willing to sell us sufficient DS3662s, but only in surface mount form. We acquired enough to make another run of QBones and/or Unibones.</p> <p>That left the other issues, and sorting out how to make surface-mount driver chips swappable for failure or misuse.</p> <p>After going heads down for a few months, we have the answer: the new QBone Dual.</p> <div class="align-center"> <p><img alt="The QBone Dual DVT." src="https://decromancer.ca/images/qbone-dual-dvt.thumbnail.jpg"/></p> <p><b>Design Verification Test unit. Final product will look a bit different.</b></p> <p></p> </div> <p>What's cool about the new QBone Dual? Well:</p> <ul class="simple"> <li><p><strong>No Beaglebone.</strong> We've integrated the entire TI Sitara CPU, DDR3, and support circuitry right into QBone Dual. No surprise costs!</p></li> <li> <p><strong>Fits within a standard QBus dual-wide slot.</strong> We took extra care to ensure DEC's original QBus specs were respected:</p> <ul> <li><p>Above: Conductive: .343" (8.71mm), Non-conductive 0.375" (9.525mm)</p></li> <li><p>Below: .063" (1.6mm)</p></li> </ul> </li> <li><p><strong>A refined back panel.</strong> From left to right: handle (not shown), USB-A, microUSB, midplane Ethernet RJ45 connector, 10x status LEDs, User button, 4-position piano DIP switch.</p></li> <li><p><strong>All configuration via DIP switch</strong>. No more jumpers! We even printed the reference chart right on the PCB for you.</p></li> <li><p><strong>Swappable drivers on SODIMM-sized boards</strong>. Do <strong>not</strong> put DDR RAM in these! The pinout is custom to QBone Dual. Each board holds 6x DS3662 drivers. Due to extremely limited supply, we won't be selling these separately, but we <em>will</em> be providing an exchange service for our customers who have failed driver chips.</p></li> <li><p><strong>I2C expansion via qwiic/Stemma QT connectors.</strong> There will only be 2 of these on the final product, not 4, but here's a preview of what you can do with parts from Sparkfun or Adafruit:</p></li> </ul> <div class="align-center"> <video controls="" height="480" width="640"><source src="https://decromancer.ca/images/qbone-dual-i2c-test.mp4" type="video/mp4">Your browser does not support the video tag.</source></video> </div> <p> </p> <ul class="simple"> <li><p><strong>Backward compatible with existing QBone accessories.</strong> You still get 2x QBone-compatible serial ports and the 14-pin expansion port. These are now resettable 1A fuse protected, as are the I2C connectors.</p></li> </ul> <p>First shipments of QBone Dual to you will be in <strong>January 2025</strong>. (Sorry, we were hoping to have these to you for the holidays - timing didn't quite work out.) We'll start <a class="reference external" href="https://decromancer.ca/qbone/">accepting orders</a> after the new year; the price will be slightly less than we sold QBones for.</p> <p>If you'd be interested in paying more for a QBone Dual Yukon Gold collector's edition, with many of the same upgrades as last time, please <a class="reference external" href="mailto:support@decromancer.ca?subject=I'm%20interested%20in%20a%20Yukon%20Gold%20QBone%20Dual!">get in touch</a>. We'll start planning for those as soon as these are well into production.</p> <p><em>Keep up with us on Bluesky at</em> <a class="reference external" href="https://bsky.app/profile/decromancer.ca/">@DECromancer</a>, <em>and let us know how you want to use the new</em> QBone Dual <em>in 2025!</em></p>