AD7877 Analog Devices, AD7877 Datasheet - Page 42

• 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

AD7877
GPIO REGISTERS
GPIO registers are written to using an extended 8-bit address.
The first four bits of the data-word are always 1111b to access
the extended writing map. The next four bits are the register
address. This leaves 8 bits for the GPIO data.
Register Name: GPIO Control Register 1
Write Address:
Read Address:
Default Value:
Type:
Table 22.
Bit
0
1
2
3
4
5
6
7
Name
GPIO2_ALEN
GPIO2_DIR
GPIO2_POL
GPIO2_EN
GPIO1_ALEN
GPIO1_DIR
GPIO1_POL
GPIO1_EN
[1111] 0000
11011
0x000
Read/write
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Description
If this bit is 1, GPIO2 is an interrupt source for the ALERT output; clearing this bit masks out GPIO2
as an interrupt source for the ALERT output
This bit sets the direction of GPIO2
0 = output
1 = input
This bit determines if GPIO2 is active high or low
0 = active low
1 = active high
This bit selects the function of AUX2/GPIO2
0 = AUX2
1 = GPIO2
If this bit is 1, GPIO1 is an interrupt source for the ALERT output; clearing this bit masks out GPIO1
as an interrupt source for the ALERT output
This bit sets the direction of GPIO1
0 = output
1 = input
This bit determines if GPIO1 is active high or low
0 = active low
1 = active high
This bit selects the function of AUX1/GPIO1
0 = AUX1
1 = GPIO1
Rev. D | Page 42 of 44
GPIO registers are read like all other registers, by writing a 5-bit
address to Control Register 1, then reading DOUT.
See the GPIO Configuration section for information on
configuring the GPIOs.
Data Sheet