The Microship Status Reports

Microship Status 2/2/94 by Steven K. Roberts

In This Issue:

Control Network Update
Control Project Status
Other Updates
Cookin'! Lots of updates in the past few days....

Control Network Update

First, the Microship Control Network continues to occupy center stage, as far as effort is concerned. We have completely eliminated the noisy RJ-11 phone wiring that I was hoping to get away with <sigh> and I've made a braided cable of three twisted pairs that so far supports five nodes. Initial tests are very encouraging... last night I wrote a test program (rather unimaginatively called SCANLOOP), and it successively polls the five New Micros FORTH boards currently connected (Serial, Audio, Video, Battery, and Distrib). After making the Easy-A connection to each, it issues the FORTH word "HEY," which simply causes the chosen board to reply with something on the order of "I am the AXBAR!" Works fine, and ran all night.

As I noted before, this does not yet support multitasking, but a couple of interesting alternatives are under development. I'll report more on that soon... but it looks like each of these little boards will be running a multitasker that allows both the application and the interepreter to operate independently, with serial data interrupting the processor and subsequently being added into a ring buffer if the Easy-A selection is valid. The good news at the moment is that we appear to have stable communications -- the current cable is about 25 feet long and it's even running reliably without termination.

By the way, I've just ordered a set of three level-converter boards to allow the RS-422 console on a node board to converse with a standard RS-232 terminal. This will be immensely useful in the lab, where 7 project teams are competing for time on the hub console. One converter will become part of the boat, allowing emergency bypass of the hub in case of hardware failure.

Now that we have established communications (though still not robust -- the networking code disappears on power cycles, since I haven't yet had much luck injecting it into the 68HC11's internal EEPROM), the students working on control projects are getting more into the hardware. Nobody has actually interfaced anything to a FORTH board yet, but that should be happening in a few days...

Control Project Status Notes

AuXBAR: The audio crossber team (Jason Corley and Isaac Chu) has been making excellent progress on developing the central crosspoint data structure, which is also being used by the Serial and Video groups. Jason has demonstrated FORTH tools to make and break connections, find the first free bus, and clear the array; Isaac is writing some of the high-level tools that interact with the host. They're planning to interface the audio boards this weekend, pending availability of ribbon cable and headers.

SeXBAR: The serial crossbar team (Dan Sebald and Jeff Simon) is focusing on two areas. Dan is working on the board itself, with four Mitel 8816s, I/O headers for 16 control lines and 32 pairs of serial lines, and an array of "level constrictors" that constrain incoming RS-232 signals to a +/- 5V range that fits within the supply limits of the crosspoint chip. This strategy worked well on BEHEMOTH -- we just use back-to-back 4.3V zeners to ground, with a 1.2K input resistor to limit the current. Meanwhile, Jeff is thinking about some of the networking issues that go beyond the crosspoint itself... this is the board that will allow the hub to select its own console.

ViXBAR: Delon Levy has selected the Mitel 88V32 for this, which is architecurally similar to the 8816 but has a number of internal ground paths to minimize crosstalk at video frequencies. Each chip (PLCC package) is a 4x8 matrix; three of them will support 16 inputs and 8 outputs with any four connections active at a time. He is currently researching distribution amplifiers to allow one source to drive multiple loads, and we're awaiting parts for board fabrication.

HUB: The hub team (Michael Bream and Chris Tuft) has been involved in the whole issue of bringing the network online, and has not yet begun the actual application software. Much of this work in development tools and networking, however, is critical to subsequent efforts, so this is all essential groundwork. Michael has also configured and patched most of the FORTH boards, with 11 now ready for network connection.

ULTRASONIC RANGING: Carl Mascarenas has reverse-engineered the LED display drive on the ranging system, and is writing the FORTH code to convert it to BCD.
GPS/NAV: Henry Xia is in the FORTH learning curve, and I packaged a 2-channel serial card and a FORTH board on an aluminum panel to support the GPS. He has also decoded the NMEA sentences and is ready to start on the interface software -- as I write this, he's in there working on the serial board software.
SOLAR MANAGER: Mohammed Sarhadi has performed initial tests of an LM10-based current measurement circuit, designed to produce an output proportional to the voltage drop across a .1 ohm resistor in the ground leg of each photovoltaic module. He will also be looking at the charge bus voltage with a divider, and array temperature with an LM335. He's currently investigating analog multiplexers for routing all this into the 68HC11 8-channel A/D converter.

Other Project Updates

Jeremy Heath is building a clamping system to mount a 2-meter J-Pole antenna on the roof of the engineering building without drilling any holes (being in an engineering building without antennas has been rather embarrassing!). This will let us get a packet radio station going, start monitoring local ham repeaters, and -- with a trip to the roof to swap antennas -- hobnob on the HF nets. It will be the key to firing up a packet-linked manpack GPS system.

Len Wanger at the San Diego Supercomputer Center has outdone himself... he has created three images of the virtual Microship integrated into real scenes! Check these out via Mosaic on our World Wide Web server (nrl.ucsd.edu).

The Ampro 286 computer that will be the dedicated user interface to the control system has been receiving attention from Frank Araullo, Dan Yang, and me this past week... but we don't have it running yet. Latest suspicion is that we've been borrowing the wrong kind of monitor -- we need VGA. Also, a Sharp color TFT 6" diagonal LCD should be coming soon... and it will also display video from the crosspoint switch.
Speaking of computers, my SPARCstation 1+ is back. This was donated by Sun a couple of years ago, and has been on loan to my manager's husband for a while. Now that it's here, the next step is to get it on the network along with everything else. The Information Networking Team is meeting here Sunday to discuss all the ethernet issues, as well as the organization of our Mosaic page.

Robinson-Nugent is no longer in the business of making Quick-Connect IDC prototyping boards, alas, so I'm trying to track down contacts at Vero. This is a low-profile alternative to wirewrap that will significantly speed custom logic board fabrication. The Serial and Video groups are doing handwiring on perfboard...
The lab is now much more open and accessible -- we've upended the cockpit mockup, cleaned the worksurfaces, added project boxes, and generally attempted to fight off creeping entropy. As the ShipNet comes online, we'll be spreading it all around the lab to allow many projects to coexist.

Finally, there's now a 3x5 cardfile in the lab, clearly labeled "CDT Box." Inside, there are cards for jobs that needs to be done (but not jobs that would justify full-scale student projects!). I've had dozens of generous volunteer help offers... now we have a collection of things that need to be done. If you want to contribute a bit of time to the Microship project, please wander by and browse the box...
Those are the headlines... back to it!

Steve