So, to save you N900/Maemo-lovers the trouble, here's a nice list:
Hardware specifications:
OMAP34xx SoC (The main chip)
TMS320C64x/C64x+ DSP CPU and Instruction Set Reference
ARM Cortex A8 specification
ARM Architecture Reference Manual (For ARMv6 and earlier.)
Note that this revision of the ARM Architecture Reference Manual is outdated. The ARMv7 one which applies to the Cortex-series is not yet released for the public. I have no idea why they're still keeping it a secret, but you can apply for a copy here. Registration is free of charge.
The information definitely missing in this revision are the new ARMv7 instructions, as well as the whole NEON instruction set, but there are probably other things as well.
Maemo.org seem to have links to all the hardware not so far listed here. The video camera, accelerometer and the FM radio transmitter among other peripherals. So it's a nice supplement.
Platform specifications (ABIs):
Unix System V ELF base specification
ELF specification from the ARM EABI (extends on the former)
ARM ELF supplement from CodeSourcery
The Unix System V ELF base specification is pretty old, and barely applies to the x86 architecture. So the ELF ARM EABI document extends on that one for the ARM architecture. The last document is a supplement to the previous ARM ELF supplement, which nails down some things which applies to Linux only. The ARM EABI is a bit vague, since it is meant for multiple platforms. The CodeSourcery supplement handles that.
Libraries/APIs:
OpenGL ES 2.0.24 specification
Ah, OpenGL ES 2.0 with vertex and fragment shader support! iPhone users should be envious. Since the OMAP3 SoC supports OpenGL ES features beyond the OpenGL ES 2.0 core, I'm sure it has some extensions as well. Be sure to check the Khronos extension registry for specifications on those.
If you feel something is missing which you can't find here nor on the maemo.org wiki, tell me in the comments so I can add it here.
Happy coding.
