FreeCalypso > hg > freecalypso-reveng
view 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 |
line wrap: on
line source
Seeking to understand the 16-pin interface between the main PCBA and the keypad. Both connectors (the one on the main PCBA and the one on the underside of the keypad) have silkscreen with pin numbers around them, but the numbers in these silkscreen labels don't match: per the main PCB silkscreen, pin 1 is toward the edge of the phone, whereas per the keypad underside silkscreen, pin 1 is toward the middle. Here I will use pin numbers per the main PCBA silkscreen. Geometric centre of the footprint is at (3923,456) in steve-m's L8 scan. Pin 8: connected to massive copper flood, almost certainly GND. Pin 9: connected to a copper fill that's islanded by some traces, so it may or may not connect the same massive fill (GND?) as pin 8. In this island there is a largish solid-connect via at (3915,475) and two smaller ones at (3766,539) and (3911,507). On L7 these vias connect to massive copper flood - definitely GND. The keymap given in OsmocomBB (confirmed to be correct) indicates that the main keypad ought to use KBC0 through KBC3 and all 5 KBR lines. The 3 side buttons use KBC4 and KBR1 through KBR3. Let's try tracing the KBC and KBR lines of interest from the Calypso. Tracing KBC0, Calypso ball N4: goes to via at (4122,380). Found it on L2, goes to a larger via at (4130,444). Found it on L7, trace disappears into the edge grind-down damage.