EVAL-AD7877EBZ Analog Devices Inc, EVAL-AD7877EBZ Datasheet - Page 36

• 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

AD7877
Register Name: Control Register 2
Write Address: 0010; Read Address: 00010; Default Value: 0x000; Type: Read/Write.
Table 17.
Bit
0
1
2
3
4
5
6
7
8
9
10
11
Name
TMR1
REF
POL
FCD0
FCD1
PM0
PM1
ACQ0
ACQ1
AVG0
AVG1
TMR0
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Description
LSB of conversion interval timer
MSB of conversion interval timer
Selects internal or external reference
Indicates polarity of signal on STOPACQ pin
LSB of first conversion delay
MSB of first conversion delay
This delay occurs before the first conversion after powering up the ADC, before converting the X and Y
coordinate channels to allow settling, and after the last conversion to allow PENIRQ precharge
LSB of ADC power management code
MSB of ADC power management code
LSB of ADC acquisition time
MSB of ADC acquisition time
LSB of ADC averaging code
MSB of ADC averaging code
00 = ADC and reference powered down continuously
For the following codes, regardless of PM bits, the reference is always powered down if the REF bit is 1:
01 = ADC and reference powered down when not converting
10 = ADC and reference powered up continuously
11 = ADC powered down when not converting, reference powered up
00 = 4 clock periods (2 μs)
01 = 8 clock periods (4 μs)
10 = 16 clock periods (8 μs)
11 = 32 clock periods (16 μs)
00 = no averaging (1 conversion per channel)
01 = 4 measurements per channel averaged
10 = 8 measurements per channel averaged
11 = 16 measurements per channel averaged
00 = convert only once
01 = every 1024 clock periods (512 μs)
10 = every 2048 clock periods (1.024 ms)
11 = every 16,384 clock periods (8.19 ms)
0 = internal reference
1 = external reference
0 = active low
1 = active high
00 = 1 clock period delay (500 ns)
01 = 256 clock periods delay (128 μs)
10 = 2048 clock periods delay (1.024 ms)
11 = 16,384 clock periods delay (8.19 ms)
Rev. B | Page 36 of 44