usbtinyisp not showing up as a Mac OS X device

USB AVR Programmer and SPI interface. Adafruit's USBtinyISP.

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Wawona
 
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usbtinyisp not showing up as a Mac OS X device

Post by Wawona »

Just finished building my usbtinyisp. Plugged it into my Powerbook running Mac OS X 10.4.11. Green light on the usbtinyisp is on.

Problem: no device is showing up on /dev.

If I use the very same cable to plug it into an Arduino, a device shows up as /dev/cu.usbserial-A4001ttB, so it's not the cable or the USB port.

I thought that the Mac doesn't need any additional drivers to be installed, but maybe I'm mistaken.

I looked over the board for any obvious soldering problems, and checked a few key voltages. Any further diagnostic tips would be much appreciated.

Thanks for your help,

Steve

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rglenn
 
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Post by rglenn »

The USBtinyISP doesn't act as a serial port, and thus won't show up in /dev. You'll need to use avrdude to access it through the libusb library (which, I admit, might be an overly technical way to describe it).

How are you trying / intending to program with the USBtinyISP?

Wawona
 
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Post by Wawona »

rglenn wrote:The USBtinyISP doesn't act as a serial port, and thus won't show up in /dev. You'll need to use avrdude to access it through the libusb library (which, I admit, might be an overly technical way to describe it).

How are you trying / intending to program with the USBtinyISP?
Thank for the reply, rglenn.

I was intending to use avrdude to program an ATmega168 on a breadboard, per the tutorial on the Sparkfun site, but using the usbtinyisp:
http://www.sparkfun.com/commerce/presen ... BEE-2-Code

But what do I enter for the -P parameter of avrdude? All of the Mac AVR tutorials out there talk about finding the USB device by just doing an "ls /dev/cu.*". Nothing looks obvious to me as the USB device.

I'm using the OSX-AVR toolset plus the 5.4 version of avrdude.

Thanks,

Steve
Last edited by Wawona on Mon Jan 28, 2008 5:15 pm, edited 1 time in total.

Entropy
 
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Post by Entropy »

You don't specify anything for the -P

It's hard to describe, but libusb basically allows an application to interact directly with the USB stack. (In some ways, it's a USB-only variant of the "drivers in userspace" projects that have recently been integrated into the Linux kernel.)

avrdude will use libusb to look for a specific USB Vendor/Product ID and interact directly with it. As a result, the USBTinyISP will never show up as a regular device in /dev - All that matters is that it shows up with the correct VID/PID in lsusb on Linux or whatever the equivalent is in OSX.

All you need to supply avrdude is "-c usbtiny" plus the other programming options. No need for -P.

timv
 
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Post by timv »

Nice explanation, Entropy. I was just curious because I don't have a USBTinyISP, but I had been wondering what was going on in there.

Wawona
 
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Post by Wawona »

Entropy wrote:All you need to supply avrdude is "-c usbtiny" plus the other programming options. No need for -P.
Thanks so much for the help, Entropy. It worked. -- Steve

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