Evaluation Board Overview; Motherboard - Analog Devices EVAL-ADP8860 Manual

EVAL-ADP8860

EVALUATION BOARD OVERVIEW

MOTHERBOARD

INT/EXT SUPPLIES
JUMPER SELECTION
VBATT LED
INDICATOR
VDDIO LED
INDICATOR
VBOARD LED
INDICATOR
EXTERNAL
TARGET
CONNECTOR
RESET (nRST)
PUSHBUTTON
The EVAL-ADP8860 motherboard provides the interface
signals to the ADP8860 parallel backlight IC. These include
2
the SDA and SCL lines for I C or the control line voltages for the
hardware interface modes (nRST and nINT).
The CY68013A from Cypress Semiconductor Corporation
provides the USB interface and I
frequency is 100 kHz. The M24C64R serial EEPROM provides
the USB address of the board. The interface voltage is selected
with the VBOARD header on the board and is set to 3.3 V by
default.
Typically, the daughterboard is inserted directly into the 2 × 20
pin header of the motherboard. The 8-pin header, J29, on the
top of the motherboard can be used to connect external supplies.
EXTERNAL SUPPLIES
DAUGHTER BOARD
CONNECTORS
BACKLIGHT LEDS (7 MAXIMUM) AND
INDIVIDUAL JUMPERS SELECTION
Figure 29. Motherboard
2 2
C signals. The selected I C
Rev. 0 | Page 14 of 24
USB CONNECTOR
BACKLIGHT/KEYPAD KEYPAD LEDS (10 MAXIMUM) AND
LED SELECTION JUMPER INDIVIDUAL JUMPERS SELECTION
(UP TO THREE CURRENT LEVELS)
The VBATT OKAY, VDDIO OKAY, and VBOARD OKAY
LEDs located at the top left of the board light up when the
board is powered from the USB cable or external supplies are
connected to J29 and the LK1 to LK3 jumpers are set in the
EXT position. It is possible to choose several supply combi-
nations. For example VBOARD, which supplies the motherboard
ICs, can be provided from the USB while VDDIO and VBATT
are provided externally. The motherboard contains three LDOs,
generating the default supply voltage as indicated in Table 1.
Table 1. Power Supply Options
LK8 to LK10 in
Supply Line USB Position
VBATT Internal: 3.7 V
VDDIO Internal: 2.7 V
VBOARD Internal: 3.3 V
Jumper LK4 selects the supply voltage for the daughterboard
phototransistors. With the jumper in EXT_VS position, the supply
voltage +VS comes from the external target. With the jumper in
VBOARD position, +VS is supplied by the VBOARD rail.
PHOTOTRANSISTORS
BIAS VOLTAGE JUMPER
SELECTION
LK8 to LK10 in
EXT Position
External: 2.3 V to 5.5 V
External: 1.7 V to 5.5 V
External: 2.7 V to 3.6 V