FreeCalypso > hg > freecalypso-reveng
comparison pirelli/keypad @ 61:2bc45eb8818d
Pirelli PCB RE: attempt to trace out KBC/KBR lines stopped by grind-down damage
| author | Michael Spacefalcon <msokolov@ivan.Harhan.ORG> |
|---|---|
| date | Sun, 01 Dec 2013 23:59:56 +0000 |
| parents | |
| children | 023d55d76b28 |
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| 60:1e797f846563 | 61:2bc45eb8818d |
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| 1 Seeking to understand the 16-pin interface between the main PCBA and the keypad. | |
| 2 Both connectors (the one on the main PCBA and the one on the underside of the | |
| 3 keypad) have silkscreen with pin numbers around them, but the numbers in these | |
| 4 silkscreen labels don't match: per the main PCB silkscreen, pin 1 is toward the | |
| 5 edge of the phone, whereas per the keypad underside silkscreen, pin 1 is toward | |
| 6 the middle. | |
| 7 | |
| 8 Here I will use pin numbers per the main PCBA silkscreen. | |
| 9 | |
| 10 Geometric centre of the footprint is at (3923,456) in steve-m's L8 scan. | |
| 11 | |
| 12 Pin 8: connected to massive copper flood, almost certainly GND. | |
| 13 | |
| 14 Pin 9: connected to a copper fill that's islanded by some traces, so it may or | |
| 15 may not connect the same massive fill (GND?) as pin 8. In this island there is | |
| 16 a largish solid-connect via at (3915,475) and two smaller ones at (3766,539) | |
| 17 and (3911,507). On L7 these vias connect to massive copper flood - definitely | |
| 18 GND. | |
| 19 | |
| 20 The keymap given in OsmocomBB (confirmed to be correct) indicates that the main | |
| 21 keypad ought to use KBC0 through KBC3 and all 5 KBR lines. The 3 side buttons | |
| 22 use KBC4 and KBR1 through KBR3. Let's try tracing the KBC and KBR lines of | |
| 23 interest from the Calypso. | |
| 24 | |
| 25 Tracing KBC0, Calypso ball N4: goes to via at (4122,380). Found it on L2, goes | |
| 26 to a larger via at (4130,444). Found it on L7, trace disappears into the edge | |
| 27 grind-down damage. |