manual: cleanup of 5V power mode description

pull/3/head
emard 6 years ago
parent 2ddfe420a4
commit 9b6573780f

@ -118,6 +118,20 @@ If other devices are connected and powered from ULX3S J1/J2 GPIO/PMOD
connectors then more than 0.5A may be required - board can draw 2-3A connectors then more than 0.5A may be required - board can draw 2-3A
when externally loaded. when externally loaded.
On J2 connector there are 2 pins for 5V external power input
and output. They are located on top right, near pin labeled 27
and US2 connector. On PCB v2.0 and later boards, both J2 5V pins are
connected to US2 5V but there are onboard jumpers which can be
carefully cut and schottky diodes soldered on their pads to route the
5V power in and/or out of the board.
Powering only from 3.3V is not possible because switching regulators
need 5V to generate 2.5V and 1.1V.
Switching regulators use ferrite core coils L1,L2,L3 which can saturate
at magnetic fields above 0.3T. Never approach neodymium magnets
near powered board.
# Low Power Mode # Low Power Mode
RTC without battery will keep waking up the board as factory default. RTC without battery will keep waking up the board as factory default.
@ -167,17 +181,6 @@ but reconfigure USB chip to turn D18 OFF:
ftx_prog --cbus 3 DRIVE_0 ftx_prog --cbus 3 DRIVE_0
On J2 connector there are 2 pins for 5V external power input
and output. They are located on top right, near pin labeled 27
and US2 connector. Power is unidirectionaly routed using schottky
diodes.
Powering only from 3.3V is not possible because switching regulators
need 5V to generate 2.5V and 1.1V.
Switching regulators use ferrite core coils L1,L2,L3 which can saturate
at magnetic fields above 0.3T. Never approach neodymium magnets
near powered board.
# Programming options # Programming options

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