AK4184VG 参数 Datasheet PDF下载

[AK4184]

OPERATION OVERVIEW

The AK4184 consists of the following blocks:

4-wire resistive touch screen controller interface

6 columns by 5 rows keypad interface

8 GPIO pins

PWM control circuit for LED bias control

Successive approximation resister (SAR) A/D converter

Pen interrupt and key interrupt circuit

Oscillation circuit

AK4184 interfaces to the host processor through standard SPI™ serial interface.

SPI™ is the trademark of Motorola

■

Touch Screen A/D Converter

The AK4184 incorporates a 12-bit successive approximation resistor (SAR) A/D converter for determining the touch

position and pressure measurement. The architecture is based on a capacitive redistribution algorithm, and an internal

capacitor array functions as the sample/hold (S/H) circuit. The SAR A/D converter output is in straight binary format

as shown below:

Input Voltage

Output Code

FFFH

(ΔVREF-1.5LSB) ~

ΔVREF

FFEH

(ΔVREF-2.5LSB) ~ (ΔVREF-1.5LSB)

---------

---------

0.5LSB ~ 1.5LSB

001H

0 ~ 0.5LSB

000H

ΔVREF:

(VREF+) – (VREF-)

Table 1. Output Code

MS0603-E-00

9

2007/04