REF: BBONEBLK_SRM
BeagleBone Black System
Reference Manual
Rev A5.2
Page 40 of 108
6.1.5
Power Button
A power button is connected to the input of the
TPS65217C
. This is a momentary switch,
the same type of switch used for reset and boot selection on the board.
If you push the button the
TPS65217C
will send an interrupt to the processor. It is up to
the processor to then pull the
PMIC_EN
pin low at the correct time to power down the
board. At this point, the PMIC is still active, assuming that the power input was not
removed. Pressing the power button will cause the board to power up again if the
processor puts the board in the power off mode.
In power off mode, the RTC rail is still active, keeping the RTC powered and running off
the main power input. If you remove that power, then the RTC will not be powered. You
also have the option of using the battery holes on the board to connect a battery if desired
as discussed in the next section.
If you push and hold the button for greater than 8 seconds, the PMIC will power down.
But you must release the button when the power LED turns off. Holding the button past
that point will cause the board to power cycle.
6.1.6
Battery Access Pads
Four pads are provided on the board to allow access to the battery pins on the
TPS65217C
. The pads can be loaded with a 4x4 header or you may just wire a battery
into the pads. In addition they could provide access via a cape if desired. The four signals
are listed below in
Table 3
.
Table 3.
BeagleBone Black Battery Pins
PIN
DESIGNATION
FUNCTION
BAT
TP5
Battery connection point.
SENSE
TP6
Battery voltage sense input, connect to BAT directly at the
battery terminal.
TS
TP7
Temperature sense input. Connect to NTC thermistor to sense
battery temperature.
GND
TP8
System ground.
There is no fuel gauge function provide by the
TPS65217C
. That would need to be added
if that function was required. Access to 1-wire SPI, or I2C interfaces required to use a
fuel gauge will need to be accessed by using the expansion headers on the board.
NOTE: Refer to the TPS65217C documentation
before connecting anything to these pins.
