June 4th, 2009

Taipei

So I was lucky enough to join in the OLPC XO 1.5 bringup at Quanta in Taipei. This was great fun: I wrote an Openfirmware HDAudio driver and we used it to test and debug parts of the main board. I got to watch people doing cool things with soldering irons, oscilloscopes, LPC ROM emulators, and other implements of destruction. Mitch debugged the memory controller interactively using a Forth that fits strictly in cache - that's a nice trick.

Bringups are fun! I would do another :-)

Brickproofing

I bricked my OLPC XO the other week by flashing bad stuff onto the SPI FLASH. That's the 1MB flash chip that the XO boots from -- it's supposed to contain the Embedded Controller software image and Openfirmware, but when either of those is messed up then the machine won't function and can't fix itself.

So Mitch sent me a DIY debricking kit: a replacement SPI FLASH chip with working firmware and some ChipQuick to remove the old chip with. My dad and I heated up a soldering iron and eventually managed to make the transplant. That was fun! But I wouldn't want to do it that way every time :-)

Thankfully my new XO-1.5 boots from something much cooler than an SPI FLASH chip: an Artec FlexyICE ROM emulator attached to the LPC bus. The ROM emulator is seriously cool - it's an FPGA with two interfaces: LPC towards the XO, impersonating a ROM chip, and USB-serial towards my Macbook, receiving new firmware images that I'm creating. It's also open-source hardware and ships with its ~2500 line VHDL sources.

I've wanted to have FPGAs in my life for quite a while now. This feels like a step in the right direction. :-)