OMAP
TM
4 PandaBoard System
Reference Manual
Revision 0.4
September 22, 2010
DOC-21010
Page 20 of 83
VDDA_DPLL balls (G13, P9 and Y16), and on this revision of the PandaBoard, the VDDS_DV_BANK7
ball (M28). This LDO also provides power for the onboard 38.4 MHz oscillator.
The VDAC LDO is a fixed 1.8V, 50mA LDO that provides a 1.8V input to certain noise sensitive
OMAP4430 balls. The balls powered by this LDO include the VDDA_HDMI_VDAC balls (A11 and
G12).
The VMMC LDO is a programmable LDO that provides the voltage to the VDDS_MMC1 balls on the
OMAP processor (pins G7 and H7) as well as the SDMMC cardcage. This LDO is off when the board is
powered on, but is turned on and set to 1.8V or 3.0V depending on card capabilities detected.
The VRTC LDO is an adjustable LDO that provides internal voltages to the TWL6030 device. Its
possible output voltage settings are 1.8V and 2.5V and its maximum output current is 25mA. In normal
operation, it should always be set to 1.8V.
The VUSB LDO is a fixed 3.3V, 35mA LDO that provides voltage to the OMAP4430 that it uses for its
internal USB transceiver. The only ball powered by this LDO is the VDDA_USBA0OTG_3P3V ball
(ball A5).
The VPP LDO is adjustable LDO that powers the VPP_CUST and VPP_STD balls on OMAP (balls J8
and Y22). This LDO is only needed for eFuse operations and can be left disabled for normal PandaBoard
operation.
2.4.7
TWL6030 Clock Circuitry
The TWL6030 has an 32.768 KHz crystal connected across its OSC32KIN and OSC32KOUT balls. This
crystal is used by the TWL6030 to generate three output 32.768 KHz, 1.8V square wave clock outputs.
These outputs are:
CLK32KAO: always on clock connected to the SYS32K input of the OMAP4430 processor.
CLK32KAUDIO: clock connected to the CLK32K input of the TWL6040 Audio Companion IC.
CLK32KG: a gated 32.768 clock connected to the SLOW_CLK input of the LS Research
module. This clock will be off by default at reset, and must be enabled by software.
2.5
TWL6040 Audio Companion IC
The TWL6040 device is a small (6 x 6 mm, 0.5mm pitch) 120 ball PBGA that provides many functions,
primarily audio, used on the Platform. Shown below is a feature list of the major functions/interfaces
provided by the TWL6040 device.
à
A audio management system
o
PDM Interface for Audio and control
o
Analog Microphone Interface
o
Headset – speaker (32 ohm) and microphone
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