Testing! Pow!

Posted 2012.07.11 23.58 in Computers/Internet/Technology by Stephanie

All my pent-up impatience just came buzzing out all at once.

With my shiney new circuit board in ┬áhand, I started soldering up the bare minimum for testing – LiPo charging circuitry, voltage regulator, ICSP port and FTDI port. And indicator LEDs.

So far so good, the voltages were good and the LEDs worked ok. Mind you, I didn’t use the good LEDs on this. No, I already knew there’d have to be another revision because I made some mistakes on the boards…

Anyhow, power tests were passed so I added the micro-controller — an Atmel ATMega1284P — and an 8MHz resonator. Tricky soldering – the pins on the micro controller are 0.4mm wide and have 0.8mm centre-to-centre spacing. There’s 11 to a side.

My two biggest concerns at this point were that a) I might have botched up the soldering, and b) I might have totally botched up the circuit board when I laid it out.

So I plugged a programmer into the ICSP port and tested it, and presto! I had communications!

My plan was to continue using the Arduino IDE to program for this, and fortunately there was already a ‘duino based on the 1284p, called the Sanguino. Unfortunately it isn’t up to date with the latest (1.0.1) version of the IDE, and I’ve migrated everything to 1.0.1 so I ended up not using the Sanguino setup.

The only thing I did was take their 1284p bootloader, and modify it to match my board layout. Then I created my own 1284p variant in the IDE and set it to work with my customized bootloader.

I had done all that last week and without any way to test, so my first real test today was to burn my bootloader. This worked (so the microcontroller, resonator, and ICSP were definitely working correctly) but I could not write sketches from the IDE so I wasn’t sure if I had screwed up the FTDI port or not.

Further testing however revealed that my 57600baud bootloader was too ambitious for the 8MHz clock speed. At 19200baud the bootloader runs just fine, albeit slower.

So another passed test! I had working power, a working micro, working ICSP port and working FTDI port.

Next thing was to plug in a screen. That was slightly challenging as my big blunder with this board was laying out the screen at the wrong size – the holes on the board are too narrow for the holes in the screen. And I didn’t want to hook the screen up permanently since the board isn’t final. So I put in some female headers, and bent a few to fit in my misplaced pin holes.

And voilla! The screen works!

Lots of successes for a single night, but I’m not going to continue populating the board. I’ve left off all the sensors as they’re the most expensive parts (gps + compass + humidity + pressure = $85). I have to go back to the ‘drawing board’ and start fixing all the mistakes I made on the board.

I’m also running some additional tests, as I’ve noticed some problems with the ADC readings (analog, eg. temperature and voltage) that shouldn’t be happening, and I have to figure out if they are software or hardware.

Still, not bad for a single night – and it gives me stuff to work on for the next few nights.

I Hate Waiting

Posted 2012.07.11 8.45 in Pointless Blather by Stephanie

Waiting is always the worst part.

I don’t like to think of myself as impatient (although I surely am) but rather, waiting is where you lose momentum, or get distracted and something else comes up that catches your attention.

I’m the person who’ll usually kick in the extra few dollars for the rush shipping option. Unless the rush option is outrageously expensive, or isn’t available, or isn’t really ‘rush’. Or if I figure it won’t make a big difference because it’s something small that shouldn’t take very long to get through.

Anyhow, so the thing is I’m waiting for my circuit boards for the ISEB-6 MkII and I was really hoping they’d be here Friday.

Then I was really hoping they’d be here Monday.

Then I was really hoping they’d be here Tuesday.

I’m not faulting OSHPark – they’ve been great, excellent communications and the boards were finished and sent nice and quickly. It’s the mail that’s holding things up.

There hasn’t been any mail delivered here so far this week. I can’t remember if there was any mail on Friday.

It happens sometimes. I never know if there was legitimately no mail, or if the carrier is taking a wee holiday. Like when I first moved here, it was about 3 years before we had mail delivery on a Monday. That can’t be a coincidence, that there was simply no mail for anyone on the block on any Monday. It seemed a lot more likely that someone was just taking 3-day weekends.

Anyhow, I’m frustrated and impatient. I want to solder stuff; I’ve got the stuff, but I’ve got nothing to solder it to. Adding to my frustration is that I’m pretty sure the boards will have at least one mistake on them, and there’s at least two features I want to add/change.

Which means I’ll have to assemble one, identify and fix what’s wrong, tweak what needs tweaking, create a new schematic, order new boards, then be right back into the waiting game again.

Next time, I think I’ll try the rush shipping option.

UPDATE

It came it came it came it came today! Along with a few days’ worth of mail. But forget the other stuff. The OSHPark package came! Yay!