MC68HC11PH8 Datasheet, PDF (175/264 Pages) Motorola, Inc – High-density Complementary Metal Oxide Semiconductor (HCMOS) Microcomputer Unit

9
ANALOG-TO-DIGITAL CONVERTER
The analog-to-digital (A/D) system, a successive approximation converter, uses an all-capacitive
charge redistribution technique to convert analog signals to digital values.
The A/D converter shares input pins with port E:
Pin
Alternate
function
PE0
AD0
PE1
AD1
PE2
AD2
PE3
AD3
PE4
AD4
PE5
AD5
PE6
AD6
PE7
AD7
9
9.1
Overview
The A/D system is an 8-channel, 8-bit, multiplexed-input converter. The VDD AD and VSS AD
pins are used to input supply voltage to the A/D converter. This allows the supply voltage to be
bypassed independently. The converter does not require external sample and hold circuits
because of the type of charge redistribution technique used. A/D converter timing can be
synchronized to the system E clock, or to an internal resistor capacitor (RC) oscillator. The A/D
converter system consists of four functional blocks: multiplexer, analog converter, digital control
and result storage. Refer to Figure 9-1.
MC68HC11PH8
ANALOG-TO-DIGITAL CONVERTER
TPG
MOTOROLA
9-1