Archive for the ‘Wiring/Arduino’ Category

T.A.D. a Through hole Arduino-compatible Design

Sunday, June 26th, 2011

Way back when the Arduino started out, you could lay out a single sided through hole design. People were encouraged to make their own. Then along came computers without serial ports and the need for everything to be USB and suddenly you couldn’t design an Arduino without a 4 dollar surface mount chip. So some of us looked for alternatives to the 4 dollar part and wound up creating examples of what would become the UNO and Paul Stoffregon’s Teensy Series.

Last year I started looking at the MCP2200, which comes in a dip and is less than 2 dollars in small quantities. Best part is that it is really a full blown USB microcontroller the PIC18F14K50. I know some of you are listening to me (HATER OF PICS) and saying BUT YOU HATE PICS!. And I agree, its a neurotic half baked architecture without a decent open source tool chain which generally survives by throwing peripherals willy nilly and through Microchips extremely liberal engineering samples.

But I like this PIC.

And here is why. For less money, it does two things that the At90USB162 and the atMega8/16/32u2 don’t do.

1. It has i2c and usb (as well as spi).
2. It comes in a DIP (as well as packages that are smaller than either the ftdi or atmel chips)

Which puts us once again in a world where we can breadboard and build our own Arduino based designs without any extreme surface mount reflow setup. In other words we can make boards that most people can put together by themselves. So I am working on a through hole Arduino compatible design and should have the first test boards this week.

A good stubby phillips.

Wednesday, April 20th, 2011

Whenever I look at integrating avrdude into a software solution I find myself thingking about how useless the “Phillip”s bit on a Leatherman(tm) tool is and how many times I have hurt myself using it when it was the tool on hand.

MAYDAY! MAYDAY! Arduino Cult Incution — 01May11, PNCA, $35

Wednesday, April 20th, 2011

I wont be able to get you into the Illuminati Motorcycle Club,

But i can lead you down the path to the dark side.

Join me on mayday for the Next Cult Induction.

Arduino Cult Induction — 30 January 2011 — PNCA ($35)

Friday, January 21st, 2011

Day 2: Thing 2: Midiuino Prototype Design.

Tuesday, February 2nd, 2010

I have been thinking alot about what what the arduino could be and also neede a board to test some Arduino shields in a midi context.

Rapha Race Controller

Tuesday, June 24th, 2008

Rapha Sportswear has a stationary race controller prototype that they need replicated for an event next week. The first step int this process was to break out the original design into 3 boards one for input processing one for the stepper drivers and one for the processor itself. Since the customer wanted to be able to modify the code themselves in the future and expand the system an Arduino or Wiring compatible board will be used.

(The completed project)

Motor Boards

The motor boards consisted of 4 darlington transistors on the best performing heat sinks I could find.

The I/O – Processor Board.

The I/O Processor board consisted of to schmidt triggers to clean up the input and a usb to serial connection for programming and future use. The board also has 3 free ports for future use.

Breadboard Thingy (rethinking the ft323rl board)

Sunday, April 13th, 2008

I sent my son to his mom’s with one of the USB Serial boards I built along with a breadboard, an RBBA a pile of resistors and an led array. I thought about this arrangement and decided that I would try to build a breadboard attached programmer that would not be dangling off the edge of the board and in the way.

Board Positive (link to board at 600%)

A single sided ft232rl based arduino programming board.

Monday, April 7th, 2008

I was so happy with the boards I did the other day that I decided to make some small boards for the ft232 so that aidan would have a programmer for his breadboard RBBA. I made 20 of these boards .

QTY Supplier Part number description cost
1 DIGIKEY 604-00043-ND IC FTDI FT232RL USB-SRL 28-SSOP 4.02
1 DIGIKEY 490-1035-1-ND FERRITE CHIP 30 OHM 1000MA 0603 .06
3 DIGIKEY 399-1169-1-ND CAP .10UF 50V CERAMIC X7R 0805 .15
2 DIGIKEY RHM220ARCT-ND RES 220 OHM 1/8W 5% 0805 SMD .07

Link to board image at 600%

Benito: My first at90USB162 project.

Thursday, April 3rd, 2008


The Benito Board is an at90USB162 board intended for use in programming and communicating with microcontrollers which have serial based bootloaders.

Among those are the Phillips lpc21xx series ARM chips, the Dallas Semiconductor, DS500x family and Atmels using any number of STK500 compatible bootloaders.

In the case of the Atmel and Phillips chips, a reset pulse is required to put the device into programming mode. A logical trigger for this pulse is the DTR signal which is pulled low when the computer begins to talk to a given device.


Recently on….

Smileymicros wrote:

Now that they have the AT90USB82 for $2,17 each per hundred at DigiKey, I’m forced to reconsider. Why the f*ck would I continue using the FTDI part which costs $3.89 each per hundred?Smiley

It was not the first time I had had this question posed. Paul Stoffregen was talking about the new at90usb82/162 chips a few months back, its cheaper than the ftdi232 and has at least 2 driverless public usb-serial implementations: Dean Camera’s and Atmel’s. The best part is that it has a built in usb based bootloader and its a fully programmable AVR microcontroller. I thought it would be perfect to replace the ftdi ft232 series chips and to build an stk500 programmer with built in usb to boot. It seemed like the thing to do for many reasons.


The sample code from both Atmel and MyUSB are based mostly on the AT90USBKey so I started with the schematic from that and cut out everything that I didn’t need. (a careful rereading of the datasheet says I am missing a 1uf cap here can you find it?).

A little hard to read

Click for larger image.

Compared to the the ftdi boards I have been working on the parts count is pretty high but I am banking on flexibility to make it worth while.

board positive

Click for link to positive at 600%

For the prototype I used my usual 1.5 sided board technique where the ground plain is brought to the top of the board and the alignment can be off by a couple of mm. The leds are some super bright ones in a plcc4 package that I have several hundred of. The pads in the eagle library for the are HUGE. I turned over the eagle files to Monty Goodson of who has lots of experience at getting things to be small so hopefully the final board will be a lot smaller.

In the mean time feel free to use the Positive image above to create your own board

The Programming Header

At the moment I have a very Avr centric view of the universe. For that reason the programming header that made the most sense was a combination of a serial connection with the 6 pin isp connection. For target boards based on other processors such as the DS5000 and the LP21xxx the SPI pins can be repurposed and the software adjusted accordingly.

Using the built-in boot-loader

When you get power, usb, crystal, reset and hwb wired you can enter the chips usb boot-loader by holding HWB low during reset. If you have a mac like me and look look at the usb section of your system profiler you should see the following:

device AT90USB162DFU:Version:    0.00

Bus Power (mA):    500

Speed:    Up to 12 Mb/sec

Manufacturer:    ATMEL

Product ID:    0x2ffa

Serial Number:    1.0.5

Vendor ID:    0x03eb

You can now program the chip using FLIP if you are running winblows (sic) or dfu-programmer from sourceforge stands for Device Firmware Update.

Running dfu-programmer looks like this.

$ dfu-programmer at90usb162 erase$ dfu-programmer at90usb162 flash --debug 20 USBtoSerial.a90

target: at90usb162

chip_id: 0x2ffa

vendor_id: 0x03eb

command: flash

quiet: false

debug: 20

device_type: AVR

------ command specific below ------

validate: true

hex file: USBtoSerial.a90

Validating...3182 bytes used (25.90%)

$ dfu-programmer at90usb162 start

I made the .a90 file from my modifications to Dean Camera’s sample code (to be described later) with the following voodoo.

avr-objcopy -R .eeprom -O ihex USBtoSerial.elf USBtoSerial.a90

Now on top of the blinking lights on the board an entirely different device is attatched to my usb port.

The “Driverless” Serial Device.

The USB standard is a lot about throwing several thousand dollars down so you can play as a member. Fortunately for the rest of us there are a couple of generalized devices that have generic definitions. one is the HID (human interface device) and the other is a CDC communications device under the CDC a class of devices is defined which looks like a modem (ACM). If a device says its one of these and acts accordingly most well developed operating systems will load a generic driver for them and just work. (and then there is windows which still requires a .inf file to load the generic driver). 

Atmel’s Code Samples.

As much as I love Atmels processors it is a constant source of irritation that their best tools are only made avaliable on the windows operating system. It was nice to see that the sample code for Atmel was avaliable for avr-gcc and I ran it up only to find myself picking through 5 layers of slashes “\”. This is not just a preference it is bad coding practice. (to quote an old co-worker of mine “Its Rubbish — Bin it!)

So I ran it up made it work and started looking at alternatives.

This lead me to Dean Camera’s MyUSB library. Though it is still in development it is still easier to understand and work with than Atmel’s Code.


When compiling Atmel’s CDC code I wound up with a linker error complaining that crtusb162.o did not exist After recommending AVRMackPack for nearly 6 months I thought I had found my first bug. After rebuilding my own version of tool chain and digging around I found that it is a known bug and should be fixed in future releases. In the mean time the fix is easy. Either copy it from the avr3 library into your source or link the directory to avr35 where the linker should find it.

#cd  /usr/local/AVRMacPack/avr-4/lib/#ln -s avr3 avr35

Building the Firmware with MyUSB

The firmware linked below under resources implements a USB serial port which produces a 2ms *reset pulse instead of DTR. It is based on the USBtoSerial Demo from version 1.3.2 of the MyUSB library. To build it unpack the MyUSB library into your work area. Then under the MyUSB library directory create a directory called Projects and unpack the Benito firmware into the Projects directory. If you have xcode (v>2.4) and AvrMacPack you can open the project and build it. Other platforms will have to adjust the Makefile to match their environment. the “make program” target defined in the make file uses the dfu-programmer utility so you can program the device using its built in bootloader.


By using Dean Camera’s MyUSB library I was able to create a serial programmer which plugs into Linux and OSX and it “just works”. I was able to produce the reset pulse in firmware and it continued to “Just Work”. You can see it above plugged into a modern device RBBA board running Limor Frieds AdaBoot. I was able to do this in a very short amount of time and while the hardware is slightly more complicated than the ft232 boards the cost at 100 boards is actually cheaper.

Moving Forward

In the photo below you can see my prototype boards (both sides) next to an ft232rl based programmer with a capacitor based “auto reset hack”. The board on the bottom shows the connection between an at90USB82 and a phillips Arm chip.

On the Atmel side the next step is to implement an STK500 based programmer using the SPI port on the at90USB162. I expect that this will be a farely easy adaptation however I may revisit the DS500x chips that I have first and work out the best way to switch between the software modes. first. From there it would also be a no brainer to adapt the firmware for the lpc21xx chip pictured above.




Arduino Programmer

Friday, March 28th, 2008

This was started at Bulky Prototype

It is part of the way that I do programming on the avr platform and the Arduino.

I was using the programming half of a a bulky prototype that I have been working on to program an RBBa based maze solving mouse and I looked at the pile hanging precariously off of the coffee table and thought to myself.

“I need to just build one of these. “

The finished product
Modifying Sparkfun Board. to fit in the box the input side
flea assembly blinkin lights in place
test run Translucence done  

So I did.

The programmer is based on the Auto-Reset Hack and the AdaBoot bootloader. The reset is pulled by putting a capacitor on the DTR line of the serial interface which is also the bootloader interface. Most people put the cap on the Arduino but I put it on the programmer (where it belongs). This programmer was built using the ftdi ft232rl breakout board sold by sparkfun. I had to trim it down to get it to fit in the pretty blue box i bought at Tap Plastics. The chip out of the box presents two of its 4 gpio (general pourpose i/o) pins to indicate when serial is being sent and recieved. I wired a pair of very bright leds that I had to them and then tried to pipe the light to the corners using some translucent plastic tubes and hot glue. It looks pretty cool!