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REF: BB_SRM_xM
BeagleBoard-xM System
Reference Manual
Revision C2
Page 56 of 163
o
Current measurement via SW
The other functions are covered in other sections in this document and are grouped by
their overall board functions. The explanation of the various regulators found on the
TPS65950
is based upon how they are used in the board design and are not intended to
reflect the overall capability of the
TPS6595
0 device. Please refer to the
TPS65950
documents for a full explanation of the device operation.
7.7.1
Main Core Voltages
The
TPS65950
supplies the three main voltage rails for the processor and the board:
o
VDD1 (1.2V, adjustable)
o
VDD2
(1.3V)
o
VIO_1V8
(1.8V)
The
VOCORE_1V3
defaults to
1.2V
at power up, but can be adjusted by software to the
1.3V
level.
Figure 26
is the interfacing of the
TPS65950
to the system as it provides the
three main rails.
7.7.2
Main DC Input
The main supply to the
TPS65950
for the main rails is the
VBAT
rail which is a nominal
4.2V. Each rail has a filter cap of
10uF
connected to each of the three inputs. A
.1uF
cap
is also provided for high frequency noise filtering.
7.7.3
Processor I2C Control
The various components in the
TPS65950
are controlled from the processor via the I2C
interface. I2C_0 is used to control the
TPS65950
device.
7.7.4
VIO_1V8
The
VIO_1V8
rail is generated by the
TPS65950
VIO
regulator. The
VIO
output is a
stepdown converter with a choice of two output voltage settings: 1.8 V or 1.85 V. The
voltage is set by configuring the VSEL bit (VIO_VSEL[0]). When the VSEL bit is set to
0, the output voltage is 1.8 V, and when it is set to 1, the output voltage is 1.85 V.
When the
TPS65950
resets, the default value of this LDO is 1.80 V; the processor must
write 1 to the VSEL field to change the output to 1.85 V. The default for the BeagleBoard
is 1.8V. This regulator output is used to supply power to the system memories and I/O
ports. It is one of the first power supplies to be switched on in the power-up sequence.
VIO does not support the SmartReflex voltage control schemes. VIO can be put into
sleep or off mode by configuring the SLEEP_STATE and OFF_STATE fields of the
VIO_REMAP register.
Summary of Contents for XM C2
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