Add test points for test rig

[charlespax]

We will have to add test points to the board for programming and testing.

[charlespax]

In the next revisions let's add test points to the bottom side. We just need to add points for things not currently on the 2x3 SMD header. Between the ICSP header and the added test pads we should be able to do the following externally.

• Power the device on and off
• Communicate with the i2c devices
• Read the voltage across the thermocouple connector
• Apply a voltage across the thermocouple connector
• Talk to the ATtiny85 over USB
• Program the micronucleus bootloader
• Program the firmware

I suppose we should breakout these items:

• USB V+
• GND
• USB D+
• USB D-
• SDA
• SCL
• TC+
• TC-

I think we actually get all this for free once the ICSP header is moved to the bottom of the PCB.

[kehribar]

After the SMD parts are soldered, all of the required test signals are exposed to a possible testbed without any change even with the current v0.3 PCB.

If the ICSP connector stays at the top, we can even reach to thermocouple soldering pads directly.

Is that sounds OK to you?

[charlespax]

Okay. Let's keep it on top.