REF: BBONEBLK_SRM
BeagleBone Black System
Reference Manual
Rev A5.2
Page 97 of 108
To calculate the amount of the pin that extends past the Point of Contact, use the
following formula:
Overhang=Total Pin Length- PCB thickness (.062) - contact point (.079)
The longer the pin extends past the contact point, the more force it will take to insert and
remove the board. Removal is a greater issue than the insertion.
8.5
Signal Usage
Based on the pin muxing capabilities of the processor, each expansion pin can be
configured for different functions. When in the stacking mode, it will be up to the user to
insure that any conflicts are resolved between multiple stacked cards. When stacked, the
first card detected will be used to set the pin muxing of each pin. This will prevent other
modes from being supported on stacked cards and may result in them being inoperative.
In
Section 7.1
of this document, the functions of the pins are defined as well as the pin
muxing options. Refer to this section for more information on what each pin is. To
simplify things, if you use the default name as the function for each pin and use those
functions, it will simplify board design and reduce conflicts with other boards.
Interoperability is up to the board suppliers and the user. This specification does not
specify a fixed function on any pin and any pin can be used to the full extent of the
functionality of that pin as enabled by the processor.
8.6
Cape Power
This section describes the power rails for the capes and their usage.
8.6.1
Main Board Power
The
Table 18
describes the voltages from the main board that are available on the
expansion connectors and their ratings. All voltages are supplied by connector
P9
. The
current ratings listed are per pin.
Table 18.
Expansion Voltages
Current
Name
P9
Name
Current
GND
1
2
GND
250mA
VDD_3V3B
3
4
VDD_3V3B
250mA
1000mA
VDD_5V
5
6
VDD_5V
1000mA
250mA
SYS_5V
7
8
SYS_5V
250mA
:
:
GND
43
44
GND
GND
45
46
GND
