[E3-hacking] E2 hackery & coding

[David Given]

Matt Evans wrote:
[...]
> Great, thanks!  Will have a play with that, looks fun. :)

Prex looks rather nice. Dead simple but sufficiently powerful to be
useful. Rather like Minix, but more flexible and better laid out. All
the work of one guy, too. It's worth playing with the PC bootable floppy
image.

[...]
>  From distant vague disassembly memory, the NAND routines take a  
> "struct nandDevice *" and all of the FTL and IO stuff indirects  
> through this.

Hmm. The routine I found at 0x4d18, which I got from rifling through the
 code that searches for BOT files, doesn't seem to take one of these...
see boot/arm/ae2/head.S, boot/arm/ae2/bootinfo.c.

It's at times like this that I find myself hoping that the PBL symbol
tables might fall off the back of a lorry... unlikely, though, given
that it's probably based on some commercial embedded OS executive.

[...]
> PS: You got a scope?  The EXP serial port's buffered through a couple  
> of transistors IIRC, your bare serial port on the MCU may still  
> work...maybe? :)

Someone's offered me a logic probe --- er, sorry Andy, I forgot to get
back to you. But as I'm currently swamped with Nanowrimo and another
coding project it'll have to wait until December. I want to figure out
the E1 serial port, as well.

Semirelated: what's the easiest way of hooking up an I2C/SPI device to a
PC? Given that most computers these days have about a dozen such buses
in them, it should be easy --- but I'm not convinced about the wisdom of
connecting random bits of dev hardware to critical peripheral buses.

-- 
David Given
dg at cowlark.com