BeagleBone DVI-D with
Audio Cape
System Reference Manual
Revision A1
Page 18 of 28
5.2
DVI-D Interface
5.2.1
Main Expansion Headers
The BeagleBone DVI-D with Audio Cape reduces the number of LCD data signals from
24 to 16. The output quality of 16-bit color is very similar to a 24-bit; however, more
signals on the expansion header can be available for other capes.
This cape uses the power rail SYS_5V to power the User LED’s, EDID I2C signals to the
DVI-D (HDMI) connector and the connector itself. The remaining components are
powered by power rail VDD_3V3. In addition to the monitor EDID, the Board ID
EEPROM on the DVI-D cape can also be accessed via I2C2 signals.
5.2.2
Bus Transceiver
LCD data and control signals are buffered through 74AVC32T245 which is a 32-bit dual
supply bus transceiver. The 74AVC32T245 also features configurable voltage translation
and can operate within voltage range of 1.4V-3.6V. Direction-control (DIR) and output-
enable (OE) inputs determine which direction the device transmits data. LCD signals
from the main expansion headers are at 3.3V level and the buffered output from the
74AVC32T245 are also at 3.3V; thus, no voltage stepping up or down is needed. Figure
4 shows the LCD signals buffered through 74AVC32T245.
