Posts

Regulator board

I’m pretty happy with this. It’s a USB to 3.3 V 1 A supply using a AMS1117 linear regulator. I used the SMT version as the pin spacing is fine for veroboard and I can hide it away on the bottom of the board.

FTDI serial adapters and Chrome OS

Looks like I’ve run into my first problem: FTDI based USB to serial adapters don’t work as they seem to be automatically disconnected shortly after plug in. I suspect that it’s udev running the brltty rules, not finding a assistive device, and aborting.

chromium

Looks like I’ve run into my first problem: FTDI based USB to serial adapters don’t work on Chrome OS as they seem to be automatically disconnected shortly after plug in. I suspect that it’s udev running the brltty rules, not finding a assistive device, and aborting.

ARM Chromebook as a primary machine

I’m going to see if my Samsung ARM Chromebook can be my primary machine. I’ve put a crouton Ubuntu chroot on a SD card (so it survives the kids dropping out of developer mode) and will mainly SSH into it.

Using clobber in machine descriptions

‘clobber’ ensures that the register is free before entering and after exiting an instruction. Therefore you can’t use it to say a register is used then destoryed by an instruction such as LOADACC, (X+) on X.

Extreme optimisation

GCC is crazy. It recognises a printf(‘foo\n’) and turns it into the equivalent puts(‘foo’) instead. builtins.c has all types of similar transformations including printf(‘%c’, v) to a putch(v) and printf(‘%s’, v) to fputs().

Canterbury innovation incubator

The Cii seems interesting. It needs more publicity – this is the first time I’ve heard of it in my fifteen years in Christchurch.

Adding new relocation types

For bfd, add them to the comment block in reloc.c then run ‘make headers’. One more make after that gets it through to bfd.h

binutils / bfd target magic

So the BFD architectures listed in bfd.h are actually defined archures.c in a big comment block at the start of the file. This is split out and fired into the documentation, many bfd-in-xx.

Python on an embedded system

I like Python. I want to use Python everywhere. Hmm. Sounds more like an addiction. The question is, is Python suitable as a glue language on a embedded Linux system?