AVR Dragon vs slow clock rates

I am using the Atmel AVR Dragon board for debugging. For $50, its a great tool. The AVR Dragon supports virtually all AVR devices, and works with AVR Studio to support Atmel assembler and GCC C code and in-circuit debugging.  It also works with other tools, such as the command line AVRDUDE utility. 

Code complete

I finished the code for the sensor board.  I plan to use an ATtiny44 with 4K Flash program memory.  The code compiles to 3720 bytes, so it seems there is room. 

Actually, it doesn't compile.  The Chibi uses an SPI interface.  The ATtiny series doesn't support SPI in the way that ATmega and above do.  An ATmega SPI works like a USART: you write a byte into a register and it gets sent.  In the ATtiny, you write a byte into a register, and then have to manually toggle the SCL line to shift the data out.  A silly "defeature" Atmel did so they could offer devices in different price tiers. 

But, I have just two days left to complete my contest entry.  So I am putting the code aside and working on costing the BOM, a quick power analysis, and writeup.  The writeup will have my known todo items in it.  I think full disclosure will be better than sending in code that won't compile and letting them discover it.

I'm off to Digikey to get prices now.

Good progress

I finished up the last bit of coding this morning, and made stubs for the RF routines.  Rather than face the problem of deciding on an RF solution, I decided to go ahead and try to get the code to compile.

It wasn't pretty.  Coding late at night results in repeating mistakes like "uint_8" instead of "uint8_t", and lOts of subtle capItalIzation errors.  I should typedef something easier than uint8_t, but it makes the code a little more obscure to someone looking at it later, such as judges.

Light at the end of the tunnel

I finished coding most of the main controller today.  Reducing the user interface to something more manageable really helped.

Not an Arduino

This is my "main controller" board for the Atmel design contest.  The ground pour pretty completely fills in the white spaces, so I am showing the board here without them so you can see all the lovely traces.

The SMT part in the center is an ATmega328.  The 6-pin connector on the left is the same pinout as an Arduino serial programming port.

So why didn't I just design an Arduino shield?

Well, I tried that.  Between the Arduino shield connectors and the interface connectors I need, the board was a mess of pins.  The ratsnest was also a mess.  The routing looked like it would take at least as long as this board, and for contest judging purposes, the elegance of the solution and BOM cost were not what I wanted.


On the upside, I can fall back to using Arduino boot loader and Arduino libraries if I need to save time. 

Things that eat up time

Atmel's AT42QT2160 uses a 28-lead QFN/MLF package. The datasheet for this part doesn't have package dimensions! So I searched around and found that their ATmega168PA/328P also comes in the same package. But that datasheet has dimensions for for a 20-pin QFN (which the 168P does not even come in). Thanks Atmel, you are a ton of help today.

So after wasting time searching, I'm stuck calculating what I hope are the 28-pin package dimensions, and if I'm wrong, eventually I'll be wasting a LOT of time redesigning my board.

Atmel Smart RF

First step: figure out what I'm going to use for wireless.

I need to keep in mind the goals: use as many Atmel components as possible, keep cost low, and minimize power consumption.

Atmel Arrow Smart Design Challenge

I submitted a design proposal to Atmel's AVR design contest back in October. The grand prize is a Smart Car. I figured winning a new car would be fun.

On Friday, they notified me that I had made it into the semi-finals, along with up to 100 other entries.