AD7877 Analog Devices, AD7877 Datasheet - Page 31

• Manufacturer Part Number: AD7877
• Description: Touch Screen Controller
• Manufacturer: Analog Devices

Specifications of AD7877

• Resolution (bits): 12bit
• # Chan: 9
• Sample Rate: 125kSPS
• Interface: Ser
• Analog Input Type: SE-Uni
• Ain Range: Uni (Vref),Uni 2.5V
• Adc Architecture: SAR
• Pkg Type: CSP

Data Sheet
If the ALERT source is a GPIO, then masking out the interrupt
by clearing the corresponding ALEN bit to 0 or removing the
source of the interrupt on the GPIO pin causes ALERT to go
high again.
If the ALERT source is an out-of-limit measurement, writing a
0 to the corresponding status bit in the alert status/enable
register causes ALERT to go high. However, the status bit is set
to 1 again on the next measurement cycle, if the measurement
remains out of limit. The ALERT source can also be masked by
clearing the relevant bit in the alert status/enable register to 0.
Rev. D | Page 31 of 44
Table 12. GPIO Configuration
EN
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
A change in the data register causes a change in the output voltage on the pin.
A change in input voltage on the pin causes a change in the data register bit.
DIR
X
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
POL
X
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
ALEN
X
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
Data Bit
X
0
1
0
1
0
1
0
1
1
0
1
0
0
1
0
1
2
2
2
2
2
2
2
2
Pin Voltage
X
1
0
1
0
0
1
0
1
0
1
0
1
0
1
0
1
1
1
1
1
1
1
1
1
AD7877
ALERT
X
1
1
1
1
1
1
1
1
1
1
0
1
1
1
1
0