MC68HC05JJ6 Datasheet, PDF (103/216 Pages) Freescale Semiconductor, Inc – General Release Specification Microcontrollers

General Release Specification — MC68HC05JJ6/MC68HC05JP6
Section 8. Analog Subsystem
8.1 Contents
8.2 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .103
8.3 Analog Multiplex Register . . . . . . . . . . . . . . . . . . . . . . . . . . .106
8.4 Analog Control Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . .111
8.5 Analog Status Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .115
8.6 A/D Conversion Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . .118
8.7 Voltage Measurement Methods . . . . . . . . . . . . . . . . . . . . . . .128
8.7.1 Absolute Voltage Readings . . . . . . . . . . . . . . . . . . . . . . . .129
8.7.1.1 Internal Absolute Reference. . . . . . . . . . . . . . . . . . . . . .129
8.7.1.2 External Absolute Reference . . . . . . . . . . . . . . . . . . . . .130
8.7.2 Ratiometric Voltage Readings. . . . . . . . . . . . . . . . . . . . . .131
8.7.2.1 Internal Ratiometric Reference . . . . . . . . . . . . . . . . . . .131
8.7.2.2 External Ratiometric Reference . . . . . . . . . . . . . . . . . . .131
8.8 Voltage Comparator Features . . . . . . . . . . . . . . . . . . . . . . . .133
8.9 Current Source Features . . . . . . . . . . . . . . . . . . . . . . . . . . . .134
8.10 Internal Temperature Sensing Diode Features. . . . . . . . . . . .134
8.11 Sample and Hold . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .134
8.12 Port B Interaction with Analog Inputs . . . . . . . . . . . . . . . . . . .135
8.13 Port B Pins as Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .135
8.14 Port B Pulldowns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .136
8.15 Noise Sensitivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .136
8.2 Introduction
The analog subsystem of the MC68HC05JJ6/MC68HC05JP6 is based
on two on-chip voltage comparators and a selectable current
charge/discharge function as shown in Figure 8-1.
MC68HC05JJ6/MC68HC05JP6 — Rev. 3.2
Freescale Semiconductor
Analog Subsystem
General Release Specification
103