Key facts
- Brand
- Analog Devices
- Model
- AD7877
- Industry
- Industrial
- Documents
- 5
- Languages
- EN
- Last added
- 2012-08-02
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Analog Devices AN-738 AD7877 Touch Screen Controller Driver Application Note
This document provides an application note (AN-738) for connecting the Analog Devices AD7877 touch screen controller to an Intel PXA25x processor running the Windows CE operating system. It includes a sample driver written for the PXA25x CPU family that utilizes the hardware SPI controller and communicates via a single GPIO pin. The driver supports advanced features such as programmable acquisition delays, averaging, conversion sequencing, and contact resistance calculation.
Read onlineAnalog Devices AD7877 specifications
| Resolution | 12 Bits |
|---|---|
| Throughput Rate | 125 kSPS |
| Operating Temperature Range | -40°C to +85°C |
| Supply Voltage (Vcc) | 2.7 V to 5.25 V |
| Internal Reference Voltage | 2.5 V |
| Package Type | 32-lead LFCSP |
Source: Analog Devices AD7877 Touch Screen Controller Datasheet
All Analog Devices AD7877 documents by type
Ratings, dimensions and ordering codes, for selection and design work.
How to use the product for one specific task, with worked examples.
Questions answered in these manuals
What processor family is this driver specifically written for?
The sample driver is written for the Intel PXA25x CPU family.
From: Analog Devices AN-738 AD7877 Touch Screen Controller Driver Application Note
Does connecting the AD7877 require external pull-up or pull-down resistors?
No, neither pull-up nor pull-down resistors are required because they are included on-chip in the AD7877.
From: Analog Devices AN-738 AD7877 Touch Screen Controller Driver Application Note
What is the purpose of the STOPACQ pin on the AD7877?
The STOPACQ pin allows the device to monitor an external signal and disable input acquisitions during noisy periods, such as when an LCD refresh signal is active.
How does the STOPACQ feature affect acquisition timing?
If the STOPACQ signal becomes active during an acquisition cycle, the current acquisition is aborted and restarted from the beginning once the signal deasserts.
What is the resolution of the AD7877?
The device features a 12-bit resolution.
From: Analog Devices AD7877 Touch Screen Controller Datasheet
Does the AD7877 include an internal reference voltage?
Yes, it includes an on-chip 2.5 V reference.
From: Analog Devices AD7877 Touch Screen Controller Datasheet