MC9S08RG60 Datasheet, PDF (178/232 Pages) Motorola, Inc – Microcontrollers

Analog Comparator (ACMP) Module
13.1 Features
The ACMP has the following features:
• Full rail-to-rail supply operation.
• Less than 40 mV of input offset.
• Selectable interrupt on rising edge, falling edge, or either rising or falling edge of comparator
output.
• Option to compare to fixed internal bandgap reference voltage.
13.2 Block Diagram
The block diagram for the analog comparator module is shown below.
INTERNAL
REFERENCE
ACBGS
ACPE
INTERNAL BUS
STATUS & CONTROL
REGISTER
ACIE
AC IRQ
ACF
ACMP1+
+
–
ACMP1–
INTERRUPT
CONTROL
Figure 13-2 Analog Comparator Module Block Diagram
13.3 Pin Description
The ACMP has two analog input pins: ACMP1– and ACMP1+. Each of these pins can accept an input
voltage that varies across the full operating voltage range of the MCU. When the ACMP1+ is configured
to use the internal bandgap reference, ACMP1+ is available to be as general-purpose I/O. As shown in the
block diagram, the ACMP1+ pin is connected to the comparator non-inverting input if ACBGS is equal to
logic 0, and the ACMP1– pin is connected to the inverting input of the comparator.
178
MC9S08RC/RD/RE/RG
Freescale Semiconductor