VUSBTiny AVR SPI Programmer

after making a usbtiny isp programmer and using it for 6 months, i was looking at making another one for carrying around. i like the simplicy of the usbtiny isp design but would like to make it even smaller and take less parts. one thing in the original design that i want to change is to eliminate the use of clock crystal. one solution i found is that v-usb drivers supports the 16.5Mhz internal oscillator on attiny25/45/85 devices. so i start out this project to have usbtiny isp employs v-usb for usb communication. the immediate benefits is that it saves space and have less component counts (no more crystals).


usbtiny

description from http://www.xs4all.nl/~dicks/avr/usbtiny/

USBtiny is a software implementation of the USB low-speed protocol for the Atmel ATtiny microcontrollers. Of course, it will also work on the ATmega series. The software is written for an AVR clocked at 12 MHz. At this frequency, each bit on the USB bus takes 8 clock cycles, and with a lot of trickery, it is possible to decode and encode the USB waveforms by software. The USB driver needs approximately 1250 to 1350 bytes of flash space (excluding the optional identification strings), depending on the configuration and compiler version, and 46 bytes RAM (excluding stack space). The C interface consists of 3 to 5 functions, depending on the configuration.


vusb

description from http://www.obdev.at/products/vusb/

V-USB is a software-only implementation of a low-speed USB device for Atmel's AVR microcontrollers, making it possible to build USB hardware with almost any AVR microcontroller, not requiring any additional chip.

video on construction and usage

Step 1: Features and parts

* programming logic from usbtiny isp, mature avr-dude support
* small foot-print
* minimal components
* powers target device


note that the io lines to the target mcus are not protected. you can add 1k-2k resistors to SCK and MOSI and protect against possible wrong connections


references

based on the works found at

v-usb from framework http://www.obdev.at/vusb/
usbtiny isp http://www.xs4all.nl/~dicks/avr/usbtiny/

parts list

* attiny45/85 (85 is more easier to come by)
* 3.6v zener diodes (1n747,BZX79,..avoid 1W types)
* 68ohm resistor x 2
* 1.5K resistor
* mini breadboard 170 tiepoints
* usb cable (dollar shop usb printer cable is fine)
* 1k/2k resistors for io lines protection (optional)

tools required

* a working avr programmer (yes, it's a catch22, we need one to make one)
* working avr programming environment

Comments

[thelinuxnerd]

I use this udev rule for my actual USBTiny but even though the id is the same it makes me use sudo for the vusbtiny. Any ideas?

[ssokolow]

Could you clarify where the "1k/2k resistors for io lines protection (optional)" go?

Also, what benefit does the  "optional 0.1uf capacitor" bring, and where does it fit in the circuit diagram? I'm feeling really fuzzy today and I'm having trouble working backwards from the photo of the breadboard.

[simpleavr]

io line resistors protects the device when u accidentally connect high-voltage input and output pins. most builds don't use them to make the project footprint smaller.
the 0.1uF capacitor is just a bypass cap to stablise power supply (like any other projects). if u have one, put it it.
there are many successful builds of this project. google vusbtiny and u can find other's experience / modification to make it work.

[ssokolow]

I haven't tried but I can imagine it might work nicely to solder SMD resistors between two adjacent perfboard holes for compact I/O line resistors (using a heat gun to keep both melted at once) similar to what spless did with all of his resistors in the photo he posted.

As for the I/O line resistors, I got that but I'm not sure where they're supposed to go in the circuit diagram. (That's also my second question about the bypass cap since, lately, I've been jet-lagged and my free time coincides with the time I'm too dozy to make sense of how the breadboard photo maps to the circuit diagram.)

[etuardu]

Thank you for this guide, I succeeded in programming both an AtTiny45 and an Atmega328.
Note that in this last case I had to wire pin4 of J2 to the Atmega328's SCK (that is pin 19), not to the SCL (that was pin 28).
And I was on Windows7 64bit, if anyone cares.

[spiess]

This is really a great little project! I built it on a little stripe of of prototype board and arranged it in such a way that one end of the prototype stripe also serves as a usb plug.

Every thing worked perfectly on the first try - so big congratulations for presenting such a useful project and making things so simple and the instructions so precise!

Thanks!!!

[icarus74]

Great tutorial. I am porting this to a protoboard.

Can the 68Ohm resistors be replaced with any other values (47Ohm, 100Ohm...) and the 150K one be replaced by another value say 1K or 2.2K ?
Would avoid burning fossil-fuel to get only those 2 from the store. Rest, I have pretty-much everything.

Also for your USB printer cable hack, can you explain the header connections ? You only seem to have Vcc and D+ connected to the header, and GND, D- isn't clear from the pic, if they are on their own headers or just plain terminated (left floating).

[simpleavr]

here are my understanding...
. the 68ohms are current limited (to protect the pins), so u should make them as close to 68 as u can. 47ohm definitely works. sometimes even better than 68ohms if u have a long usb cable.
. the 1.5k is a pullup, so anything between 1k to 5k is fine.
. follow the schematic / diagram, there are only 6/7 parts in this, the schematic also make notes of the 4pin header position. if u are talking about the usb cable itself, they can be different colored wires inside, u sould use a multi-meter to sort out which is which. i.e. measure between the contacts on one end against the 4 exposed wires against a usb pin-out diagram.

good luck on your build.

[_Ludo]

Did anybody test it under Win7? I got an error saying that the installation could not be done!?

[icarus74]

As far as I can tell, reading various posts at the Objective-Development site (& forums), very few people seem to have had success in using V-USB under Windows 7. Apparently, some initial / early Win 7 (that too, possibly only on 32-bit mode), installation did work, but people do seem to have issues.

Here's one such thread: http://forums.obdev.at/search.php?fid[]=8&sid=ffe64be8b944f53757abea58c378899a

[nis123]

It is sufficient if i just flash the given HEX file using SinaProg???

[simpleavr]

never used sinaprog before. if it can accept hex file and works for u in flashing avrs, yes, u can use it as my hex files are no different. u do need to toggle the fuse bit on your target device and u should find out how it's done w/ sinaprog.

[8N1]

The usbconfig.h says:
"Please note that D+ must also be connected to interrupt pin INT0!"

Can you tell me what you have done to avoid that?

Thanks for sharing!

[simpleavr]

thanks for your interest.

the default D+ pin is INT0, but it can be changed, for attiny45/85 layout, i used portb.3, we can re-define USB_INTR_VECTOR to be the "pin change" interrupt. and any one of the 6 io pin level change will trigger the interrupt, which includes portb.3.

note that if u are also using some other higher priority interrupts this may fail.

inside usbconfig.h, toward the end of the file, u can see the various options.

#define USB_INTR_VECTOR SIG_PIN_CHANGE

//#define USB_INTR_VECTOR INT0_vect
//#define USB_INTR_VECTOR PCINT9_vect

[putyn]

hey im trying to build a smd version of your tiny avr programmer (will post pictures as soon as i get it finished) and im waiting for the board to arrive anyway my question the programmer uses the 8mhz internal oscillator ?
so i can order this part ATtiny85V-10SU or this ATTINY85-20SH :) ?

[simpleavr]

@putyn

use the 20mhz version (attiny85-20??), we need to use a internal oscillator clocked at 16.5Mhz to avoid external crystals.

for more technical details if u need, go to the vusb site for explanations.

good luck w/ your project.

[putyn]

ok thanks for your answer will order this ATTINY85-20SH - can you take a look at my schematic and design if i post them ?

[simpleavr]

not sure, i think this is the most simple programmer already? are u changing anything? If not, build it and if u ran into problem. Post a comment here I am sure either myself or someone can help.

[John_Edward]

Thank you for this guide, I made my tiny programmer with the help of this :)
I made mine to a piece of stripboard, and used an Arduino to program the chip.
I'll link my materials here, so people can see how it would fit to a stripboard.
The board could be made smaller if I used more wires instead of jumpers, but It's small enough for me like this :)

I don't take any responsibility for wrong schematics though, these are made from memory and might not be correct:

http://koti.mbnet.fi/johnedwa/misc/vUSBtiny_stripboard_v1.PNG
http://koti.mbnet.fi/johnedwa/misc/vUSBtiny_stripboard_v1_schematics.PNG

[silverwindro]

That ATtiny is bigger, my ATtiny45V is smaller than that one in the clip.
Or am i wrong?

[vishwaiit]

What are all the avr micro controllers that can be programmed using this programmer.if any one has the PCB layout,i would be interested.

[zgr95]

i just finished a pcb layout sent me a message and ill email it to you

[The Real Elliot]

Awesome. It's a mashup of two of my favorite projects, and the result is the most minimal USB programmer I've seen yet!

[msajib_06]

1.Can i make this with an ATMega32?
2.If so what modifications do i need to make?

[simpleavr]

no u cannot swap w/ an atmega easily, this circuit relies on the special 16.5mhz internal oscillator (only available on tiny25/45/85) so that no crystal is needed.
if u have an atmega, u should build the usbasp, it is also very simple to build.

[bill.stewart]

If you've got an Arduino, you can use it as an ISP programmer. That doesn't mean you don't want to build this one - it can be handy to have a dedicated programmer, and use the Arduino for fancier stuff. On the other hand, if you're building one of these, you probably don't have a high-voltage programmer, so you may want to splurge and have a couple extra ATtiny85's around in case anything goes wrong.

[simpleavr]

100% correct, you will want to also build a HVP, i did bricked a tiny45 building this project. so i build a tiny2313 based "standalone" fuse reader / rescuer. that's an upcoming project awaiting write-ups. it will only do HVSP (serial hi-voltage) and works only with 8pin and 14pin avrs. here's a picture http://www.simpleavr.com/avr/avr_fuse.jpg

[hardwarehank]

So when is this one coming out ? :)

[simpleavr]

http://www.instructables.com/id/AVR-HVSP-Fuse-Resetter/

just finished the fuse resetter instructable, enjoy.

[hardwarehank]

Thanks!

[simpleavr]

will make an effort to deliver this one in two weeks time. thanks for your interest.

[Locosapien]

Good work. I'd like to build the HV Programmer.

[hardwarehank]

Finished my version of this today - it's awesome! Thanks! I built it on protoboard because I wanted it to be permanent. I had connected one of the wires wrong, and it didn't function as a low-speed USB device at first, but I finally figured that out, and was able to flash and verify my first chip using avdude! I might perfect a little board layout and try to adapt this to an SOIC ATTinyx5. I'll let you know and give you credit if I do.

[simpleavr]

cograts, a pleasure to learn that u had a successful built. many had built the original usbtiny (may it be ladyada's or dick streefland's version), and the parts varies a bit. ladyada's version1 part list asks for 3.3v zeners, dick's version asks for 3.6v, either way it depends how tolerate your usb host is. the bus level should be 3.3v and a 3.6v zener (w/ voltage drop) would be a good match. my experience is that 3.6v zener and lower wattage ones (400/500mw) works better.

if u make a pcb version and have (/will have) a project page i would like to link to that. sounds like u will shrink it even smaller w/ soic device.

[hardwarehank]

Also, I used 1N4728 Zener diodes I had laying around, and they worked fine - you mention "1N747" in your parts list - maybe you could mention these?

[emihackr97]

Hi, im really interested ur project, but i have 2 questions;

1. Can I use an ATtiny25-20PU??
2. Can I use this programmer with the Arduino IDE as an ArduinoISP or USBtiny??

thanks for answering,
emihackr97.


P.D: If u make a kit, i can help u distribute them.

[simpleavr]

@emihackr97
1. not enough flash space after i adopt to vusb firmware, missing about 2k, i tried to squeeze but failed.
2. yes, it's used like a usbtiny.

i don't mind if u make a kit but u really should ask usbtiny and vusb authors. i just combine the two and did not put much into this.

[_Ludo]

Hello Gents,

I would like to make it but don't have a programmer (well sounds obvious, no? :-) ). I have empty chips here, can anybody program it for me via mail exchange?

I'm in France...

[hardwarehank]

source codes are gnu gpl v2 licensed from inheritence

If you mean you used GPL libraries in your code, and are only distributing source that you wrote (ie. it's not a derivative of GPL software), you can license your code any way you want - or even copyright it. Using standard libraries and gcc doesn't mean you have to GPL your code. Just making sure that's clear. :)

I love your structable.  I'm totally going to make one of these with my ATtiny85 I have on my desk.  I wonder if I can make it even smaller using my SOIC t85s.....  Cheers!

[hardwarehank]

Oh, I see - since your work is a derivative of Dicks, so copyleft applies.  Cheers!