EVAL-AD7877EBZ Analog Devices Inc, EVAL-AD7877EBZ Datasheet - Page 5

• Manufacturer Part Number: EVAL-AD7877EBZ
• Description: BOARD EVALUATION FOR AD7877
• Manufacturer: Analog Devices Inc

Specifications of EVAL-AD7877EBZ

• Main Purpose: Interface, Touch Screen Controller
• Embedded: No
• Utilized Ic / Part: AD7877
• Primary Attributes: 4-Wire Resistive Touch Screen Controller, SPI Interface, On-Chip: Temp Sensor, Voltage Reference, 8-Bit DAC
• Secondary Attributes: USB GUI, LCD Noise Reduction Feature, 2.7 ~ 5.25 V, Wake Up on Touch Feature
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

REGISTER ACCESS SCREEN
To read and write to the AD7877 registers, click on the Register
Access tab. The screen in Figure 3 is displayed. If the dot is
green to the right of the register map, this signifies that the USB
connection between the PC and the board is active. If this
dot is red, the connection is not functional. In this situation,
the user should check that the USB port on their PC is con-
figured correctly and that the evaluation board is connected via
the USB connector to the PC.
Reading and Writing to the Registers
The register access screen gives access to all the registers on the
AD7877. A map of the AD7877’s registers is given on the left-
hand side of the screen. Details of the current selected register
appear on the right-hand side of the screen. The user can read
or write to the registers by supplying values in either hex or
decimal and then clicking on the Read or Write buttons. The
user may also write to the register by clicking on a bit in the Bit
Display section. Clicking on a bit will invert that bit’s value in
the relevant AD7877 register.
Selecting a Register
By double-clicking on any heading in the register map section, a
full list of registers relevant to that heading are displayed. Under
the Control/Alert/DAC heading, the following registers may be
accessed: Control Register1, Control Register2, Alert/Status
Enable, and the DAC register.
REV. Sp0
Figure 3. AD7877 Register Access Screen
–5–
Under the Temperature heading, the following registers may
be accessed: Temp1 (single ended), Temp2 (differential),
Temp1 High Limit, and Temp1 Low Limit. The result of
clicking on the Temperature heading is shown in Figure 4.
The TEMP2 register is selected in this example. The Temp1
reading is calibrated automatically by the evaluation software,
using the Temp2 reading.
Under the Auxiliary heading, the following registers may be
accessed: AUX1, AUX2, AUX3, AUX1 High Limit, and AUX1
Low Limit.
Under the Battery heading, the following registers may be
accessed: BAT1, BAT2, BAT1 High Limit, BAT1 Low Limit,
BAT2 High Limit, and BAT2 Low Limit.
Under the Sequence heading, the two sequencer registers, Se-
quencer Register 1 and Sequencer Register 2, can be accessed.
The GPIO registers can be found under the GPIO heading;
GPIO Control Register 1, GPIO Control Register 1, and GPIO
Data Register.
The touch screen inputs can be accessed under the X/Y Mea-
surement heading. The X+, Y+, Y– (Z2) and X+ (Z1) registers
are found here. Figure 5 shows how to access the Y+ register.
EVAL-AD7877