Evil Mad Scientist Laboratories just released Meggy Jr., an open source handheld gaming platform that includes cool chunky buttons, support for the Arduino IDE, and an 8×8 RGB LED matrix capable of displaying beautifully pixelated color images.
Definitely the coolest EMSL release of 2008 – and just in time for the holidays.
The Arduino team has released a new version of the awesome Arduino platform called Arduino Duemilanove. Improvements include automatic selection of USB vs. external power, header pins for RESET and 3.3V supply, and an easy to cut automatic-RESET-disable trace.
The wiki page includes a very helpful audio sample to demonstrate proper pronunciation of the new name.
Update 03/11/09: Kits based on this design are now for sale!
Update 12/14/10: The original AVR HV Rescue Shield kit has been replaced by the new and improved HV Rescue Shield 2. Visit the HV Rescue Shield 2 product page for information about the new kit!
As I mentioned earlier this week, I recently “lost” an ATmega168 due to flashing the configuration fuses to disable the RESET pin, without realizing that this makes the device impossible to reflash with SPI. This is particularly frustrating because the device is still 100% functional, just completely deaf to ordinary serial programmers. The only way to recover the device is using what Atmel calls “High Voltage Parallel Programming Mode” which very few programmers support, most importantly, not the USBtinyISP I otherwise love.
Fortunately, my trusty Arduino came to the rescue – I created an Arduino-based AVR programmer that uses the high voltage programming mode and can fix pesky fuses like RSTDISBL.
The Arduino has just enough IO to implement the entire HV protocol plus a “go” button. So far I have only implemented setting LFUSE and HFUSE in software, but there is no reason why the code couldn’t be extended to support chip erase and programming the entire flash as well.
The fuse programming process is simple:
Upload the HVFuse sketch to the Arduino, available for download here: HVFuse.pde
Install the shield and apply +12VDC to the terminals on the left
Wait for the red LED to turn on (if it isn’t already)
Install the ATmega to be repaired
Push the button
As soon as the LED turns back on, the AVR is fixed and ready to be put back into service!
Here is an Eagle schematic of the HV Programming shield (click to enlarge):
Update 12/17/08: An observant reader pointed out that there were three errors in the way GND/AGND, AREF and VCC/AVCC were connected on the target AVR in the original schematic. The errors have been fixed and the updated schematic is below. Apologies for any confusion this caused.