One transistor too many
From Openmoko
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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 . | 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! | + | Removing it is a nontrivial task, requiring experience and proper tools. Pavel (who wrote this page) did not yet dare to fix his fic1973. You probably can't do this at home. Be careful! |
The transistor pulls a 'reset' line on the gsm pmu. this pin on the | The transistor pulls a 'reset' line on the gsm pmu. this pin on the | ||
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debounced. It is called q1001. When the pmu is shut down for suspend-to-ram the samsung somehow generates a | 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, | 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. | + | 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 | 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 | would require changes to the gerber (labeling) and just not placing the transistor | ||
| − | does not. | + | does not. It is basically a layout-revision. |
Revision as of 23:27, 25 November 2007
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. You probably can't do this at home. 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. It is basically a layout-revision.
