We had originally intended for this article to be a scathing review of the TOP2005 programmer, one of chose cheap USB EEPROM programmers that are coming out of China these days. We bought one a while back and it was fine for standard 27C64 eproms and the like, but totally sucked when trying to read anything modern like a PIC or newer electrically erasable devices. So into the file cabinet it went to collect dust.
Fig 1 – TOP2005 Programmer
However, when we ripped the beast apart we liked what we saw. It’s a bit of a hack to an old parallel programmer we think, but the hardware looks good. A USB to parallel adapter talks to an 8051-clone microcontroller. The micro talks to a Xilinx CPLD and a Xilinx FPGA that run the pin buffers. The programmer attempts to implement a good bit of eeprom programmer fanciness such as identifying logic devices, reading manufacturers, etc. Plus, it’s portable and USB powered and oh so cheap and hackable. We REALLY wanted it to work, but it just acted like a piece of junk.
We probed the pins, snooped the USB, and disassembled the software. It’s rather cool in that when changing devices, it uploads a new bitstream to the FPGA. So in theory, this guy should be infinitely extensible if you were inclined to write new bitstreams to the FPGA and do some custom software work.
Opportunities like that bring to mind images of relaxing by the fireplace on a snowy winter’s day… While the TOP feverishly spews attacks to some micro or something, quietly blinking and churning out data. Since the programmer can supply power from 2.7v to 20v and can drive 40 pins (all with an unprotected micro and Xilinx’s), this thing could be a pretty awesome programmable test bench.
However, it couldn’t even read an ATtiny!?! We had to find out what was the problem.
Continued on Next Page…