Archive for February, 2007

USBasp Perf. Board Build

The computer I’m currently on (intel mac mini) doesn’t have a parallel port, so I can’t use the STK-200 style AVR-ISP to program/flash AVR chips. So, looking for the USB alternative, I stumbled across the USBasp. From the site, “USBasp is a USB in-circuit programmer for Atmel AVR controllers. It simply consists of an ATMega48 or an ATMega8 and a couple of passive components. The programmer uses a firmware-only USB driver, no special USB controller is needed.”

It’s cross-platform (Linux, Windows, Mac OS X), and since it implements USB as firmware in the AVR, it keeps the parts count pretty low.

I’ve gotten around to building the USBasp on a perf board, since I’m too cheap for a real pcb. I have confirmed it working on both Windows and Mac OS X (and as of today Linux too), and have used it extensively the last couple of days to write an LC7981/HD61830 driver on an ATMega32 (will post this up soon) without any problems.

There is also USBtiny, which is probably the fastest way to get up and running with USB AVR programming if you already have a parallel port STK200 clone. Like the USBasp, it implements USB entirely on the AVR firmware, but is actually more of a parallel-port to USB converter (it interfaces to an existing STK200-style AVR-ISP parallel port programmer).

USBasp Perf. Board Build - click for a high-res picture:
USBasp Perf Board Build

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JTAG Wiggler Schematic Fix

Per has brought to my attention that the JTAG Wiggler schematic on the “JTAG Wigger Clone” page has an error. I jumbled up the P4/P3 connections on the parallel port when I was adapting the schematic in EAGLE (the schematic is based on this one http://jtag-arm9.sourceforge.net/circuit.txt). I have fixed this error in the JTAG Wiggler schematic image, and I also posted the EAGLE schematic file.

Thanks to Per for bringing up the error.
I apologize for this mistake and I’ll do my best to look out for them in the future.

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