Eagle Cad Files to Dip Trace

I've fallen in love with Dip Trace. I find it so much faster to use. Unfortunately Eagle is the standard, so I still have to have it installed. I find myself wishing to edit designs that are in Eagle in Dip Trace because Dip Trace is intuitive, and it spits out Gerbers and NC Drills without any setup. There is hope.

Dip Trace comes with a couple of Eagle ULPs that will Convert eagle files to Dip Trace ASCII files that can be imported. I'm looking for a new ICSP that uses 6 pins. but all the sleek ones use the 10 pin headers, or are huge. So A trip to OSH Park and a search for ICSP and we find µUSBasp. the download link is an Eagle file so grap it, and load it into Eagle...

In the file menu there is a "Run ULP..." Item click on it.

Next an open file box opens, find the Dip Trace install folder. Mine was in C:\Program Files (x86)\

in there is a Utils folder. Open that and run Eagle_to_DipTrace_PCB.ulp

Next is a save file dialog. Save the file with a .asc extention. YOU NEED TO USE .asc AT THE END OF THE FILE NAME. not doing so will cause DipTrace to not see the file, so you have to find in in Explorer and rename it. 

Notice the little finish message at the bottom. That's it no frills. 

in a new Dip Trace PCB file, go into the file menu select import and Select DipTrace ASCII. Find your .asc file and open it.

Notice there isn't all the fanciness. board outline is broken, and all the text is missing. The labels are huge. Clean up takes only a few minutes. I generally hide the labels so I'm not concerned, I have the file and schematics so part ID's aren't needed. Everything is in it's place.

Just one more reason to love DipTrace, 

Arduino ISP

*** UPDATE ***
I mistakenly added the wrong 2x3 header. It's not a 0.1" spacing. I've corrected it and added a few LED's that you can wire up as per the Arduino ISP sketch. look for v0.2 on the board.
***End UPDATE

Completed, write up here.

For programing tiny 85 and 84 with Arduino, read the high low tech article it'll get you there fast.

Most people I imagine start with playing with AVRs via the Arduino community. Unfortunately moving from your easy to use Arduino to a bare chip isn't easy. It requires a programmer, and those can be as little as a couple of dollars on ebay for a usbtinyisp or avrisp clone. I have a nifty Arduino with breadboard mounted on a piece of Plexiglas that is great for attiny development, especially using attiny85's since the Arduino has power, and I can use it as programmer. Most starter kits come with similar setups, so alot of people have them. It's a pain to setup, and the more wires the more chances to fail miserably. and disconnecting to rapidly test is a little painful.

For the chip side of things I've ordered a few pixie85's and pixie2313 boards. so I'll have the ICSP header broken out. Adafruit has a ICSP breadboard adapter and a 6" 2x3 idc cable... for all of 3 bucks for the set. You'll need some thing similar.

Scouring the internet the solution to my woes seemed to hack a 6 pin IDC cable to use the arduinoISP and an ICSP connector. Sound good but still one of those what pins do I use moment. Adding to the complexity the UNO requires you to disable the auto reset for the serial. This requires a 10uf cap between reset and gnd. Way too much to remember every time. 

The solution is obviously a shield. Unfortunately all the ones I've found already designed are for chip sockets. and we fairly expensive for what i wanted, a cheep, easy to setup programmer board that I could give away.

So the next installment in PCB Design is the ArduinoISP header shield. The LED's are optional, they hook up with wire from "D7-D9" on the back of the board. That gives activity, error, and heartbeat. It didn't add to the price so why not. Also it the cutout on the right so that pin 9 should be exposed.

These are being ordered next week some time. So figure at the end of september I should have them tested.

A simple square inch design that straddles the arduino. I finished the design today. for the uno you need a cap. older boards might need a 120 ohm resistor, though the cap might work too.

It's a bout 5 bucks for the 3 boards. Cheap enough to give away at parties.

Memory

I've played with Arduinos for a while. The IDE is functional. The API has a really heavy abstraction. That really becomes problematic when you want to start using the ATTINY processors. Lets look at the popular AVRs

	Flash	Ram	EEPROM
tiny 2313	2K	128B	128B
tiny 84	4K	512B	512B
tiny 85	8K	512B	512B
mega 328	32KB	2k	1k

The mega 328 has enough ram to use it carelessly. It's flash size is huge. translating a basic Arduino program into a tiny2313 might be a little challenging. So lets go over a few memory tricks worth mentioning. today we're still going to be using an Arduino as a target since I have one here and most people will too.

Data types int and char are very different beasts. Char is an integer type guaranteed to be 8 bits in size, int is 16bits. so a char is 1 byte, where as an int is 2 bytes. In general, use char when you can. unsigned it'll hold numbers 127 to -126, unsigned will get you 0-255. a trick that helps at least me is declaring the following at the top of my program: unless you need to go larger, chars will make that 128 bytes last a little longer.

Macros are the next bit of memory stretching arduino doesn't teach. if you have unchanging data, or constants, a define is better than a variable. take the following:

#define NUM_PINS 4
int num_pins 4;

The first line will insert a 4 anywhere the compiler sees NUM_PINS. This allows for centralized information without using ram to do it. The second line uses 16 bits to sore 3 bits of data. a char, or unsigned char is better fit, since it only uses 8 bits.

These are basic C items that you can use in the standard Arduino stuff. To get in the habit.

Lets revamp the fade code from the arduino examples a bit. The original uses 15 bytes of memory. the bare example uses 9, so those 6 bytes are from the 3 variables. This one does it in 12 bytes.

/*
 Fade

 This example shows how to fade an LED on pin 9
 using the analogWrite() function.

 This example code is in the public domain.
 */

#define LED 9;           // the pin that the LED is attached to
unsigned char fadeAmount 10;    // how many points to fade the LED by

unsigned char brightness = 0;    // how bright the LED is we need 0 to 255

// the setup routine runs once when you press reset:
void setup() {
  // declare pin 9 to be an output:
  pinMode(LED, OUTPUT);
}

// the loop routine runs over and over again forever:
void loop() {
  // set the brightness of pin 9:
  analogWrite(LED, brightness);

  // change the brightness for next time through the loop:
  brightness = brightness + fadeAmount;

  // reverse the direction of the fading at the ends of the fade:
  if (brightness == 0 || brightness == 255) {
    fadeAmount = -fadeAmount ;
  }

  // wait for 30 milliseconds to see the dimming effect
  delay(30);
}

OSH park buys

I bought some more boards off of OSH Park. I found them helpful. Only one was my own, and that was based off of another I found but it was very big and big costs money.

LED Simple

My design but I was inspired by Greg's LED board. For a beginner or for teaching that is a better board. It allows visualization. But at 5 bucks a piece someone that has a little more understanding of electronics might like to spend less and get a little more bang.

I have a friend trying to get into micro controllers and these short cut boards can be the difference between learning or tossing a bread board across the room. I also wanted to use these on the edge of a bread board connected directly to either a 74595 or Port D of a tiny 2313/4314. So I added 2 ground pads in the upper corners so i don't have to populate the ground pad. It was a 10 minute board, the routing could be better. These are cheep, so I'm defiantly going to revise this a bit more maybe do the resistors vertical next to the header. the header is going to be slimmed down to 8 pins, the "floating" ground pin makes more sense to me, for versatility. A 4 Led version would be nice too. Also i can see a female header and rubber feet being a good fit as well.

The other boards:

Pixie85 and Pixie2313 Just simply icsp jacks with attached chips. Removes one step and a lot of little wires. That's a win win.

Sturdy Pot Adapter. Simply a briliant way to add a big pot to a bread board. I have huge fingers. I bought 9. that were 1.80 for 3. Simply awesome, every starter kit needs these. 

Firsts

I've started to get back into my highly technical side of life again. The first step is to learn more about AVR's Sure that arduino sitting on you desk is cool and all and those wires in that breadboard impress people. But when you start making real projects that you want to keep you need to do something more than put that breadboard in a box.

This is a board based on a ATTINY 2313/4313. It's very SMD, but designed for hand soldering. It's 7 breadboard rows wide(0.7 inches between the 10 pin headers) so it'll fit well. and you can solder wires when you need to make a real project, way more street cred hand soldering 0805's then 1/4 watt TH resistors.

Why a tiny 4313 when 2313's are so popular? Double the memory and they are still under 2 bucks each. I also want to play with VUSB it takes up most of the 2313's flash space. USB circuits are integrated, and not broken out to the bread board. Usb provides easy power and some real functionality. To round it off, I'll add a spot for a crystal. These have been sent to OSH Park for building. Set me back $15 for 6. I've started using DIP Trace for PCB stuff. It's faster than eagle, and parts building is less complicated. I've included gerber and dip trace files. The drawing is unfinished. I like to connect headers on the PCB vs line drawings. this makes sure i get the right pins. Unfortunately I haven't figured out how to get the PCB view back in to the drawings. but the PCB file is correct, and you can work it from there.

The row of discrete components are top to bottom: 100k ohm, 68 ohm, diode, diode, 68 ohm, 1.5K ohm

A31727CT-ND	CONN MINI USB RCPT RA TYPE B SMD	1
ATTINY4313-SU-ND	IC MCU 8BIT 4KB FLASH 20SOIC	1
CTX904-ND	CRYSTAL 12.0000MHZ 18PF T/H	1
MMSZ4685-TPMSCT-ND	DIODE ZENER 3.6V 500MW SOD123	2
311-68ARCT-ND	RES SMD 68 OHM 5% 1/8W 0805	2
311-1.5KARCT-ND	RES SMD 1.5K OHM 5% 1/8W 0805	1
311-100KCRCT-ND	RES SMD 100K OHM 1% 1/8W 0805	1
445-1273-1-ND	CAP CER 22PF 50V 5% C0G 0603	2

Gerber files and Dip trace files can be found here.

Everything was ordered today so check back in a couple of weeks when OSH Park cranks them out.