BeagleBone LCD7 Cape
System Reference Manual
Revision A3
Page 24 of 27
respectively. TPS61080 utilizes an external inductor to store and transfer energy to the
output capacitor which is connected to the Anode terminal of the LCD backlight. The
Cathode terminal is connected to the feedback (FB) pin of the device. A current sense
resistor is connected to the FB pin for a constant current output. Figure 8 shows the
backlight circuit of the BeagleBone LCD7 Cape:
Figure 8.
BeagleBone LCD7 Backlight Circuit
5.4
EEPROM
The BeagleBone LCD7 Cape has an EEPROM containing information that will allow the
SW to identify the board and to configure the expansion headers pins as needed.
EEPROMs are required for all Capes sold in order for them to operate correctly when
plugged in the BeagleBone.
The EEPROM used on this cape is the same one as is used on the BeagleBone, a
CAT24C256. The CAT24C256 is a 256 kb Serial CMOS EEPROM, internally organized
as 32,768 words of 8 bits each. It features a 64-byte page write buffer and supports the
Standard (100 kHz), Fast (400 kHz) and Fast-Plus (1 MHz) I2C protocol. Figure 8 is the
design of the EEPROM circuit.
