[gta02-core] Calypso's last dance

Rask Ingemann Lambertsen ccc94453 at vip.cybercity.dk
Sat Jul 25 02:02:06 CEST 2009

On Thu, Jul 23, 2009 at 12:08:37AM -0300, Werner Almesberger wrote:

> http://www.option.com/en/products/products/modules/gtm501/
> As far as I can tell, using the GTM501 instead of the Calypso would
> be relatively easy if we accept that the existing GSM antenna will
> be a poor fit. Specifically, the necessary changes should be:
> - addition of a 3.6 V/3 A DC-DC converter

   The discharge graph of our battery is only specified to 2.4 A. I can't
find a clear statement of the limit imposed by the protection circuit[2], it
just says 2.5 A ~ 5.0 A. It's not listed in the GTA02 current chart[3] either.

[1] http://battery.sanyo.com/en/spec/ion/UF653450S.pdf
[2] https://people.openmoko.org/tony_tu/GTA02/hardware/GTA02/CT-GTA02.pdf
[3] https://svn.openmoko.org/developers/werner/gta02-current-chart.txt

> - switch Bluetooth to UART and the modem to USB

   How well will A2DP playback work over a UART? It'd be ~1.5 Mbit/s.
Alternatively, add a USB hub. The debug board contains a Texas Instruments
TUSB2046, a four port USB 1.1 hub in a 32 pin Quad package. There's the SMSC
USB2512 (36QFN, 6x6mm) previously mentioned in another thread[4].

[4] https://lists.openmoko.org/pipermail/hardware/2009-January/000955.html

Rask Ingemann Lambertsen
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