Computing stuff tied to the physical world

AVRISP mkII w/ 5V power

In AVR on Apr 2, 2010 at 00:01

I’ve been using the USBtinyISP AVR programmer for some time now, to set the fuses, burn the boot loader, and burn the RF12demo.pde compiled sketch into each ATmega.

Trouble is, it’s slow as molasses …

So I got the AVRISP mkII programmer a while back, but the problem is that it’s unpowered. Not good for my setup, which expects power from the USB programmer:


So I went looking around for tips on how to bring 5V to pin 2 of the 6-pin ISP connector. Found this mod which uses a 5-to-3.3V regulator, and this one which draws 5V directly from the board.

I decided to tap the 5V USB power, but after the polyfuse, so that a short won’t damage the computer or USB hub as easily:


The connection is jumpered, so this can still be used in its original form when needed.

And then I spent ages chasing ghosts…

It turns out that avrdude needs a “-B 3” time adjustment to reliably program the chips. Now how am I supposed to know that!

Anyway, here’s the shell script I’m currently using on my old PowerBook, which automates it all:

Screen shot 2010-04-01 at 23.08.28.png

That last character being echoed is a CTRL+G, i.e. an audible bell to signal when the process is done. It used to be essential, since the USBtinyISP took so much time for each burn. Now, it’s clocking in at 17 seconds, and that could probably be reduced even further by combining the three separate avrdude runs.

A roughly 10-fold improvement!

  1. Out of curiosity: how do you load the RF12demo on the surface mounted atmega’s on the jeelink ? Do you press a 6-pin connector in the isp holes on the board after it has been reflowed and then use the programmer on it ?

  2. I normally use this thing to pre-load the chips –

  3. Der hier ist zum Programmieren besser als das Original und die Spannung ist per Jumper zuschaltbar (direkt oder über Diode). Mit dem Programer habe ich bisher nie Probleme gehabt und die Firmware ist stets auf Stand.

    Bei Deinen Boards werde ich den 6-Pin Header noch nachrüsten müssen, ich programmiere lieber via ISP :-)

    • Interessant, sieht gut aus… danke für den Tipp! (ja, in die Arduino Welt ist ISP immer 6-Pin)

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