This is embarrassing…
It looks like some trivial plugs in Plug Panel 1 do work, but everything of even the slightest complexity (and usefulness) is faulty :(
The Expander Plug has a completely incorrect pin allocation for the MCP23008 18-SOIC chip. Which I had to create from scratch in EAGLE, and obviously I’m still learning just how to do that. Lesson one: don’t move pins in a package around without checking their pin numbers afterwards!
Unfortunately, that means the LCD Plug I sent off a few days ago will also come back useless :(
The Thermo Plug can’t turn off its buzzer because a trace is shorted out to a pad (I guess I didn’t do a DRC), and the thermocouple interface isn’t working because the AD597 chip needs at least 5V as power supply. So much for sensing or controlling anything. Oh well, I suppose the NTC and 1-wire inputs work.
The Room Plug didn’t work with a 1-wire DS18B20 sensor, in fact it looks as if the 1-wire sensor is hooked up the wrong way around since it’s shorting out the 3.3V supply. And the EPIR sensor isn’t responding either. I haven’t tried other configurations yet.
The Clock Plug mistake was described yesterday. It’ll probably work with a DS1340 chip i.s.o. a DS1307.
The I2C Connector … well, ehm, I mixed up the AIO and DIO pins. Incredible stupidity.
Oh, yes, there is some good news – the Breadboard Connector “works”:
But then again, it’s a bit hard to mess up a tiny pcb with no electrical components on it :)
Drat. Back to the drawing board. I may need several iterations to get my act together. This will add weeks to the process. Of course it’s a learning experience, such as: lesson 2 – check and double-check, and lesson 3 – check everything again. E v e r y t h i n g !
Man, do I feel JeeSilly right now…