TODO list - any available?

Werner Almesberger werner at
Thu May 21 22:08:37 CEST 2009

?lvaro Lopes wrote:
> I decided to help you whenever possible and provided
> we're focusing on the same objectives.

Excellent, thanks and welcome !

> So far it seems most important task is to draw component schematics so
> they can be used on the diagram. However there seems to be no TODO list
> about what needs to be done. Does anyone has such a list ?

Dave has done most of the large components. What's left are a bunch of
smaller ones, e.g.,

- X1501 (crystal with ground)
- X1701 (crystal with ground, different pin numbering)
- U1702 (LDO regulator)
- U1705 (switch)
- RP2201..RP2203 (resistor array)
- B3004 and B3005 (common-mode choke)
- U4901, U4902, U4903 (logic)
- D4901..D4904, "C4902", and so on (varistor)
- U4905 (switch)
- Q4601 (transistor with resistors)
- VB4601 (vibrator)
- RP6001 etc. (filter, maybe use a better symbol as well)

Then there are the non-trivial connectors:

- CON4901 (USB)
- JK4401 (audio jack)
- CON7501 (SIM/uSD combi)
- CON7901 (WLAN board-to-board)

Two subsystems that aren't part of the "core system":

- all of GPS (76XX)
- all of BT ("BT_MODULE"): module, antenna

Not sure what our chances are to get GPS right on the first try, but we
can give it a spin, see what happens.

And a few simplifications:

- we don't need Q1501, Q1502, or R1564, because we can drive the LEDs
  directly from the CPU. The I/O pins can drive 8 mA and GTA02 uses only
  about 6 mA.

- we don't need anything on sheet 25XX, except R2502 (this should be
  on the CPU sheet anyway, got nothing to do with NOR)

- we don't need sheet 18XX

> And is there any high-level diagram depicting what you're (we're)
> trying to accomplish ?

Something like this ?

> You also want to abandon the glamo chip. You probably already replied to
> my next question, but I'll ask it: why drop it (besides lack of
> documentation),

Mainly because it provides negative acceleration.

> and which [cheap] alternatives are out there (cost, availability and
> power wise)

There's a perfectly good unaccelerated LCD interface in the 2442,
so we'll just use that. Access to main memory is much faster than
access to Glamo memory, so it'll still be faster than the
"accelerated" Glamo.

Refreshing the LCM will cost memory bandwidth, but with the Glamo
and the NOR absent, we can increase the speed of the memory bus to
just make up for that.

- Werner

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