next-generation PMU discussion / Memory 1.8V

Andy Green andy at
Mon Apr 21 15:07:56 CEST 2008

Hash: SHA1

Somebody in the thread at some point said:
| Am Mo  21. April 2008 schrieb Andy Green:
|> Somebody in the thread at some point said:
|> | Very sure our RTC should move from PMU to MPU.
|> | So is there any more need to have a backup battery for the PMU? Can we
|> share
|> | the battery between 50366 and 430?
|> |
|> | Andy: ts scanning won't keep the MPU awake, a touch is triggering a
|> | hw-interupt on the A/D-input of 430. So no touch, no op (not even
NOP ;)
|> Don't we have to go around driving X then Y plane?  Is it OK to drive
|> one plane all the time from a power POV, if that's what goes on?
|> | So anybody here who's unhappy with the MSP430FG4618?
|> | Before I start to read the next 100 pages of manual to check if it
|> meets our
|> | specs.
|> The price is a lot... I hope this price doesn't bear any resemblance to
|> the "FIC price" because it is a bit hard to defend blowing $13 on this
|> MPU.  I think we probably did some overkill needing 8K of RAM, 1K or
|> maybe 2K should be fine.
| just it makes NO difference at all.
| This is the only "model" with BGA113 footprint, and they are same
price for
| 4k - 8k and different flash-ROM sizes.

These prices are at qty 100 -- FIC will get way better pricing.
This device is:

''16-Bit Ultra-Low-Power MCU, 116KB Flash, 8KB RAM, 12-Bit ADC, Dual
DAC, DMA, 3 OPAMP, 160 Seg LCD''

There are also some choices in 64QFN package

This is 9mm x9mm 0.9mm thickness.

The BGA113 is better for sure, at 7.1mm x 7.1mm and 0.77 - 1.0mm high.

It's just possible we could do extensive bitbanging (with consequent
higher power and software complexity) and use

which is $4.90/100 in QFN.  But the ADC does not look good enough for
touchscreen... but we could define that it only detects a touch action
and not the coordinates (shares the touchscreen so it looks only while
CPU down).

If the extra bitbanging and restrictions are too crazy, your choice is
the next one that is the right size in MSP430 as far as I can make out too.

| Took me quite some hours to dig thru the TI pages and tables, but it
| there just is no other chip 430 with small footprint.
| Probably it's been silly I do this, whereas Werner as well as you both
| probably know better of this product series.
| Well somewhere I *have* to start with this task ;-), so why not here...
| /jOERG
| ps: [just kidding:] we already *have* a MPU even in GTA02. It does near
| nothing most of the time and sits inside our GSM chips. Why not use this
| one? ;-) We already paid for it.

Well it's a good point, but then we tie our core product function to
this GSM chipset :-)

- -Andy

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