View source for One transistor too many

From Openmoko

Jump to: navigation, search

You do not have permission to edit this page, for the following reasons:

  • The action you have requested is limited to users in the group: Administrators.
  • You must confirm your email address before editing pages. Please set and validate your email address through your user preferences.

You can view and copy the source of this page:

Return to One transistor too many.

Retrieved from "http://wiki.openmoko.org/wiki/One_transistor_too_many"
Personal tools

Given-away fic1973's from phase 1 (red board) had one transistor too many. That one needs to be removed for correct sleep operation. See http://people.openmoko.org/roh/Gta01b_v4_front_Q1001.jpg .

Removing it is a nontrivial task, requiring experience and proper tools. Pavel (who wrote this page) did not yet dare to fix his fic1973. Be careful!

The transistor pulls a 'reset' line on the gsm pmu. this pin on the pmu is not debounced, the other one for power (same wiring, other transistor) is debounced. It is called q1001. When the pmu is shut down for suspend-to-ram the samsung somehow generates a hard, short spike on all gpio, which would, due to no debouncing reset the gsm, which wants to send data on the serial and wakes up the samsmung -> loop. since TI says the reset is only for testing, not for regular use, we removed q1001 from the placement map. Just the name was not bumped to gta01bv5 since that would require changes to the gerber (labeling) and just not placing the transistor does not. its basically a layout-revision.