Teletext Inserter

A very long way to go with this project but all the hardware is now procured. This is the bare board still at the manufacturer complete except for the routing.

From blogpics

As for the software the command interpreter is running but doesn't have many commands yet. The settings code is installed but there are no settings to save just yet. Today's task is to generate packet 8/30 format 1. As there is no real time clock this will rely on getting synced up regularly and after power cuts.

Adulteration

At school, the extraordinary history teacher "Jock" taught us all sorts of things, not all of them on the syllabus. One of these was about adulteration of food in Victorian times. Chalk was being put in milk and flour to whiten it and bulk it up! Flour had other flours made from potato, peas and beans added for bulk. Thank goodness that doesn't happen now!

Which brings us to Penguin Biscuits. We all love that chocolate covered biscuit with a nice cuppa and a very fine tradition they are too. The ingredients include soya (bean flour) and calcium carbonate (chalk).

But nowadays due to the wonder of marketing, chalk is now a selling point ("Added Calcium") and therefore helps build childrens' bones.

Creationist Nonsense of the Day

Who needs a healthcare plan when you have this website on your side?
http://www.pray4trig.com/

This particular quote showed breathtaking ignorance:

God didn’t play any pranks on us. Dinosaurs were killed in the Flood buried under many layers of sediment in a matter of days and compressed under water deep enough to cover all the mountains of the Earth. That’s MILES of water. Incredible pressure. That’s how they became fossilized.

I can see at least five things wrong in that small quote. Everything in it is contradictory to the actual evidence. The scary thing is that nearly half of the USA population believes this nonsense.

Mattair XMega Development Board

Today a package arrived for me. Although it said "Priority" all over it, three weeks seems like a pretty poor interpretation of priority. Anyway, it was the new AVR Xmega development board from Justin Mattair . Despite the best efforts of USPS and Royal Mail to squash the box, it seems that the generous allocation of header pins provided structural support and prevented any damage. So I plugged it in and the blinkenleds demo started and the com port popped up.
Did I mention the pins? There are too many of them too close together to be able to fit more than one IDC cable header. So the cutters will trim one or two ports to size. One curious bit of design. The ground vias all have thermal relief patterns.

Demo time. A blob of solder connects one of the links required for the new demo. The instructions are a bit sparse and it said to link J15 and J27 but J15 is only needed for the mini joystick which isn't fitted anyway. Next it said remove the programming link. Where is that? I guess there is only one link that is removable. And indeed pressing the hardware button magically the unit becomes an AVRISP mkII. Where is the device driver? Hidden in AVR Studio 4 of course. Then it asks if I want to upgrade the firmware. Probably not! That is the quickest way to kill a programmer. With great trepidation I press the Program button and all the lights go out. Now what? I replace the programming link, press the reset button and we revert back to a serial device. Hmm, maybe that isn't what we wanted to do? Where is the USB/SPI bridge? I guess the USB chip needs a quick go with Flip.
So on with the jumper, hold HWB and jab at reset. Oh wow. Now we have mounted a DFU. Scrabble around for the Flip driver and "Your new hardware is installed and ready to use". So in Flip I look for the Xmega but heck, it isn't supported???? Oh, thats right, its the OTHER AVR I am supposed to be programming. Now it all programs OK and it is time to click Start Application. Bye bye DFU and hello XD200 USB-SPI configuration page. What do I do with this? Confused now. Where do I put these drive mounting commands in? Oh right. Its the magic jumper that needs to come off.
So now the terminal goes crazy flickering. That is different. Press the "any" key and wow, here are all the goodies :-)
What is the temperature? "Demo has not been written". I already knew it was 21C so that is no great loss.
Blink LEDs. Yes. blinkenleds are in full working order.
Finally a look at what I really need to be checking out. The SD card slot. And we have the magic incantations
di0
ds0
fi0
fs
fl
Wow. Now I can read my files.

Next to sort out why exporting Kicad to GC-Prevue put all my drill holes at the same location.....

It has a name! VBIT, a low cost teletext inserter

There comes a time in every project when it needs a name. This moment came when I had a pile of blueprints all with the title field empty. So VBIT is the name of this gadget. VBI is for vertical blanking interval and T is for teletext.
Isn't EDA software fun? Lucky I got all the components first and laid them out on a printout of the top layer. Why did the programmers postfix footprints with E for narrow and N for extended? So I had to swap these around. Also the SOIC pads were too small for hand soldering so I had to stretch them all by 1mm. Then the auto routing is brain dead so I had to lay out all the tracks manually. FreeRoute is very good but then I can't import the results back because the pads and tracks don't exactly line up so it fails the design rules check.
Then plotting to Gerbers is like warping back in time 30 years, when everything had to fit on a double density floppy. Why do I need to know all about drill decks and aperture lists? Madness!
So the design is now at the PCB maker but I already spotted an error. No pull-ups on the I2C. Oops. This is what it would look like if the pull-ups were fitted.

Engineering Change Note 1: pull up SCL and SDA to +3.3v using 3k3 resistors.

Should have walked home.....

New car, 1 in 8 Rodborough Hill, cotswold stone wall, heavy snowfall. What could possibly go wrong?

From blogpics

Teletext inserter

Teletext is disappearing region by region. In a couple of years there will be nothing left. Teletext will then be extinct and that would be a great loss to diversity. So I have started a captive breeding program. Now who would want a teletext inserter? They said that about the Komodo dragon and that got protected so maybe teletext has a chance too? This inserter board illustrated is ready to go off to the factory. It will be a lengthy teaching process of many months until it can insert as much as a filler packet. Re-introduction should be able to take place by summer 2010.

Trading in teletext inserters is permitted by CITES (Convention in Teletext Encoder Systems). You can help by buying one of these. They only require feeding +3.3Volts and vitamins C,V,B and S. This will be supplied as a board only and you'll need to put it in your own cage and add your own processor board.

* Analog teletext inserter
* Configurable by USB. Will run stand-alone once loaded up.
* SD card page memory. More pages than you can display!
* Packet 8/30 capable.
It isn't.....
* Broadcast quality!
* A bridge