Thanks again.

one other things, is the pins listed in the avr config correct or were they just an example?  according to the j8head jpg you have the gpio numbers should be different than those listed in your post?

The pins listed in the avrdude config are exactly how I configured my setup.  The setup I posted is what I did step by step.  Any linking information was just added for clarity, but apparently I caused confusion.  Hope that helps.

edit:

one other things, is the pins listed in the avr config correct or were they just an example?  according to the j8head jpg you have the gpio numbers should be different than those listed in your post?

Just got note from the EMUtag developer.  He has created a 'How To' Page on the EMUtag site.
Here is the link.  It is not yet linked from any other page.
http://emutag.com/howtos.php

That page also shows how to power the EMUTAG from an external DC source, but requires modifying the board... I wonder if those two schottky diodes could be placed outside of the board if one gets rid of the onboard cells and uses an external battery pack (e.g. 3x AA) as backup alongside a 5 V AC-DC adapter?

BTC

As I gained permission from the developer to direct post his file links, he asked "it would be nice if you could reserve sections for firmware flashing instructions using all 5 methods (arduino, RPi, FTDI, parport, and a dedicated AVR programmer), so that RPi method will be one of the sections."

I write this post as a set of instructions to use a Raspberry Pi to re-flash the EMUtag.   It would be great if the community could post other methods here as a one stop thread for the EMUtag flashing.  I know that Mr Clown has a post helping with Arduino / FTDI.  Csan that get copied over here?  I will do the work if it is ok.

Raspberry Pi

==============================================================

Raspberry Pi side:

Enable SPI interface by opening a terminal:
1- pi@raspberrypi ~ $ sudo raspi-config
2- select option 5 - Interfacing Options
3- select P5 - SPI
4- select Yes to the question "Would you like SPI interface to be enabled"
5- select OK
6- select Finish

Emutag side:

Solder 0.1" pitch pins to the EMTtag board. 
See this image as to the location and meaning of each pin http://emutag.com/img/icsp.jpg

****!!!! These pin numbers are physical pins numbers, not GPIO numbers and they are set up to match the programmer section below
see http://pi4j.com/images/j8header-3b-large.png
EMUtag  MOSI to pin 19 on RPi
EMUtag MISO to pin 21 on RPi
EMUtag SCK to pin 23 on RPi
EMUtag RESET to pin 07 on RPi
EMUtag GND to GND on RPi
EMUtag 5V to 5V on RPi

Preparing avrdude:

we will be compiling from source
Lifted from <http://ozzmaker.com/program-avr-using-r … y-pi-gpio/>

pi@raspberrypi ~ $ sudo apt-get update
pi@raspberrypi ~ $ sudo apt-get install -y build-essential bison flex automake libelf-dev libusb-1.0-0-dev libusb-dev libftdi-dev libftdi1
pi@raspberrypi ~ $ wget http://download.savannah.gnu.org/releases/avrdude/avrdude-6.2.tar.gz
pi@raspberrypi ~ $ tar xfv avrdude-6.2.tar.gz
pi@raspberrypi ~ $ cd avrdude-6.2/
pi@raspberrypi avrdude-6.2/~ $ ./configure – -enable-linuxgpio
pi@raspberrypi avrdude-6.2/~ $ make
pi@raspberrypi avrdude-6.2/~ $ sudo make install

Changing avrdude settings

pi@raspberrypi avrdude-6.2/~ $ sudo nano /usr/local/etc/avrdude.conf

Linux GPIO configuration for avrdude.
Change the lines below to the GPIO pins (GPIO04 as an example) I did this sucessfully connected to the AVR.

programmer
    id = "linuxgpio";
    desc = "Use the Linux sysfs interface to bitbang GPIO lines";
    type = "linuxgpio";
    reset = 4;
    sck = 11;
    mosi = 10;
    miso = 9;
;

Loading and writing firmware files:

wget http://emutag.com/firmware/ntag213-sniff.bin
wget http://emutag.com/firmware/common.eep

sudo avrdude -c linuxgpio -p t4313 -U flash:w:ntag213-sniff.bin:r -U eeprom:w:common.eep:r -U efuse:w:0xfe:m -U hfuse:w:0xdf:m -U lfuse:w:0xdf:m

==============================================================