
REF: BB_SRM_xM
BeagleBoard-xM System
Reference Manual
Revision C2
Page 104 of 163
The PWM inside the
TPS65950
can be used to alter the brightness of the LED if desired
or it can be turned on or off by the processor using the I2C bus. The PWM is
programmable, register-controlled, duty cycle based on a nominal 4-Hz cycle which is
derived from an internal 32-kHz clock. It is possible to set the LED to flash automatically
without software control if desired.
7.22.3
User Indicators
There are two user LEDs,
D6
and
D7
, that can be driven directly from a GPIO pin on the
processor. These can be used for any purpose by the software. The output level of the
processor is 1.8V and the current sink capability is not enough to drive an LED with any
level of brightness. A transistor pair,
RN1907
is used to drive the LEDs from the
VBAT
rail. A logic level of 1 will turn the LED on.
7.22.4
HUB Power Indicator
The HUB power LED,
D14
, is turned on whenever the USB HUB power is active. This
output is driven from the
TPS65950
using the
LED.
A output. The processor can control
the LED by communicating via the I2C to the
TPS65950
.
7.22.5
Overvoltage Indicators
The Over Voltage LED,
D13
, turns on whenever the DC voltage exceeds 5.3V. The
detection circuit,
TPS3803,
turns on the LED.
7.23
JTAG
A JTAG header is provided to allow for advanced debugging on the BeagleBoard by
using a JTAG based debugger.
Figure 50
shows the interconnection to the processor.
Summary of Contents for XM C2
Page 152: ...REF BB_SRM_xM BeagleBoard xM System Reference Manual Revision C2 Page 152 of 163 ...
Page 153: ...REF BB_SRM_xM BeagleBoard xM System Reference Manual Revision C2 Page 153 of 163 ...
Page 154: ...REF BB_SRM_xM BeagleBoard xM System Reference Manual Revision C2 Page 154 of 163 ...
Page 155: ...REF BB_SRM_xM BeagleBoard xM System Reference Manual Revision C2 Page 155 of 163 ...
Page 156: ...REF BB_SRM_xM BeagleBoard xM System Reference Manual Revision C2 Page 156 of 163 ...
Page 157: ...REF BB_SRM_xM BeagleBoard xM System Reference Manual Revision C2 Page 157 of 163 ...
Page 158: ...REF BB_SRM_xM BeagleBoard xM System Reference Manual Revision C2 Page 158 of 163 ...
Page 159: ...REF BB_SRM_xM BeagleBoard xM System Reference Manual Revision C2 Page 159 of 163 ...
Page 160: ...REF BB_SRM_xM BeagleBoard xM System Reference Manual Revision C2 Page 160 of 163 ...
Page 161: ...REF BB_SRM_xM BeagleBoard xM System Reference Manual Revision C2 Page 161 of 163 ...