R22 is use to pull the FLAGB output of the FPF2109 high since this
is an open-drain output.
but we actually don't read FLAGB do get the error conditions, thus
thus pull-up resistor is not required.
this change has been tested with a real simtrace device.
trace and card emulation worked with a Nokia 3310.
Change-Id: I3dd82864708f1ecb30ddbaa4c60aa600325455e2
R24 is pulling the voltage regulator output for VCC_SIM down.
it has probably been added at the same time as R15.
since we don't read VCC_SIM it is not important to have it in a
defined state.
also the card, phone, or simtrace will provide power to the card
when required (else the card load is high enough to immediately
pull it down).
this change has been tested with a real simtrace device.
trace and card emulation worked with a Nokia 3310.
Change-Id: Iaae0959b62bc9348279bc5d840addbeb28fdf98f
R15 is pulling VCC_SIM down.
it has probably been added because a load resistor is present in
the FPF2109 datasheet example application, or to not have VCC_SIM
in tri-state.
since we don't read VCC_SIM it is not important to have it in a
defined state.
also the card, phone, or simtrace will provide power to the card
when required (else the card load is high enough to immediately
pull it down).
current flowing from the other card pins back to VCC should not
happen, and if it happens this high value resistor will not have
any effect.
this change has been tested with a real device.
trace and card emulation worked with a Nokia 3310.
Change-Id: I002b1fcf1039c8910d902e476a47183172d70761
- VCC is up
- GND is down
- group the parts by functionality and use net name
- separate decoupling capacitors
- arrange groups from left input to right output
Change-Id: I2d894dd10b8b619ccbce1ae8b7e25316963157c8
the library system changed from KiCad 4 to KiCad 5.
the custom libraries have been re-added to the project, and all
symbol names have been updated.
some symbols are a bit smaller, requiring to add some wires.
Change-Id: Id8e61aab6f05c633f455ef0d338c1658a62a2c4a
the layout for the FPC cable was not existing, and the schematic
is not an actual part of SIMtrace.
the FPC cables are designed separately.
Change-Id: I9138476c96404e18161b58b7b3a7a450ce633e81
If the LDO is switched off, then even if we try to forward power from
the phone to the SIM, the current will sink inside the LDO (no reverse
current protection).
We have to make sure the impedance of the supply lanes is not too high.
Particularly bad was passing GND in 0.2mm under several resistors before
even reaching the LDO from the USB socket.
This attempts to address the major issues. Also, the input capacitor is
moved closer to the LDO once again
Kevin Redon
King Kévin
Harald Welte