Rick's b.log - entry 2020/09/22

Autumnal Equinox (Mabon)

This heralds the "official" start of Autumn, and if this morning was anything to go by...

It had been fairly warm up until recently. There were a few nights when it went down to 5°C at night, but just recently it's been in the 30s during the day, one of them recording the highest September temperature ever recorded in France.

But, alas, "nature" knows that winter is on the way. I saw a few lone swallows on Sunday, but I think they pretty much all headed south halfway through last week.

And the trees? Do you remember when I was looking forward to the cherry blossom? It seems only a month or two ago. Well, the wild cherry is starting to lose its leaves.

Wild cherry starting to lose its leaves.

As is the epic willow (actually three trees, and epic enough to fill a widescreen photo!).

Willow starting to lose its leaves.

It seems that seasons often come in pairs of extremes. We had a really hot summer. Here's hoping we don't have a really cold winter. Or one of those ones with endless weekly hurricanes

A half hour extra

So, wake at 6.50am and leave the house by 7.50am (to arrive around 8.10-8.15) to get changed, sorted out, and clock in for 8.30.

Tassimo debug port

Here is the top of the board.

Tassimo control board - top

And here is the bottom. It has been flipped to put the debug port in the same place, so you ought to be able to mentally overlay the through-board links here with those on the top of the board.

Tassimo control board - bottom (flipped)

A few further observations.

• There is no relay. That big green thing only has two pins, so it's probably a capacitor to filter input power.
• There is no transformer. It looks like it is definitely the VIPER6 gizmo providing the low voltage power.
• There's a big resistor (next to the big green capacitor). I've not metered or measured this, but at a guess it is dropping the AC voltage before it gets to the Viper chip.
  I wonder if it is dropping the voltage to ~110V? In that way, the same basic control board could be used with European and American markets by simply replacing the resistor with a wire link (and changing the pump/heater for local equivalents)? Just a guess...
• The heater is controlled by the big triac attached to the heatsink. It is a BT138.
• The pump is switched by a generic transistor. I don't actually have a clear photo of its part number, but it's the fact that it has the same aspect as a regular 2N2222. It very likely isn't, but worth noting that it doesn't have any sort of heatsink yet it's switching a pump!
• There is provision for an eight pin socket of some sort visible on the bottom of the board. I have not traced the connections, but it's location and where the through-board links are would suggest to me that it is an alternative connection point for the barcode scanner.

Tassimo control board - high voltage connections.
H - Heater; N - Neutral; L - Live; P - Pump

Here is the pinout, with pin #1 being the top most (closest the Viper) and pin #8 being closest to the corner of the board:

Looks like my guesswork wasn't that far off. Though, there may be no serial communication with the device, as the BOOT0 line controls whether the device boots from programmed firmware (normal) or the internal bootloader (for reprogramming the Flash using the serial port).
Additionally, the device has three levels of "protection". Level 0 means that hooking up to the SWD debug port can read out all of the firmware (among other things). Level 1 means that flash can neither be read nor written using the debug port or boot-from-RAM mode (to stop you uploading a reader to RAM and then running it!). And level 2? Not only is the Flash protected, but the debug port is too. This is, sadly, the most likely setting for a commercial device.

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David Pilling, 22nd September 2020, 22:44

X2 is a capacitor class, printed on the green component. You can find the Viper circuit diagrams on the web. That blue component will be something like surge protection. Since the CPU is so powerful, play games, word process. Would sort of be fun, but only impress those who knew the days that used to be.    Maybe it could mine bit coins whilst brewing.

J.G.Harston, 1st October 2020, 16:43

I checked the datestamp on something this morning and had to mentally blink a couple of times before realising that 201001 wasn't an error and I'd gone back in time. It's October already? How did that happen?

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