Chapter 15
Analog Signal Processor (ASP)
The analog signal processor (ASP) module of the MC9328MX1 consists of an ADC for touch panel input,
and a CODEC (both ADC and DAC) for voice input/output.
15.1 Features
The ASP modules offers the following features:
•
9-bit PADC for touch panel and low voltage detection
•
On-chip voltage reference for ADC
×
•
12
16-bit FIFO for PADC sample
•
Embedded touch panel circuitry
•
Supports auto and manual sampling mode
•
Programmable pen down and pen-up interrupt to interrupt handler
•
Provides data-ready and FIFO-full interrupt to interrupt handler
•
True differential input
•
Support for temperature compensation by software
15.2 ASP Signal Description
The ASP system block diagram shown in Figure 15-1 illustrates the operation of the individual modules
that comprise the ASP.
Voltage
Uip, Uin
Detect
PX2
PX1
From Touch
Panel
PY1
PY2
MOTOROLA
U
X
SWITCH
INPUT SELECT
CIRCUIT
Y
For Touch Interrupt Generation
Figure 15-1. ASP System Block Diagram
Analog Signal Processor (ASP)
SWITCH CNRL
and
INPUT SELECT
LOGIC
PADC
INTERRUPT
GENERATOR
PEN CONTROL REGISTER
SAMPLE RATE CTRL REG
COMPARE CONTROL REG
PEN SAMPLE REG (12X16-bit)
comp_int
touch_int
pen_up_int
pen_data_int
15-1