MC9RS08KA2 Datasheet, PDF (82/132 Pages) Freescale Semiconductor, Inc – Microcontrollers

Analog Comparator (RS08ACMPV1)
10.1.1 Features
The ACMP has the following features:
• Full rail-to-rail supply operation
• Less than 40 mV of input offset
• Less than 15 mV of hysteresis
• Selectable interrupt on rising edge, falling edge, or either rising or falling edges of comparator
output
• Option to compare to fixed internal bandgap reference voltage
• Option to allow comparator output to be visible on a pin, ACMPO
• Remains operational in stop mode
10.1.2 Modes of Operation
This section defines the ACMP operation in wait, stop, and background debug modes.
10.1.2.1 Operation in Wait Mode
The ACMP continues to operate in wait mode if enabled before executing the WAIT instruction. Therefore,
the ACMP can be used to bring the MCU out of wait mode if the ACMP interrupt is enabled (ACIE = 1).
For lowest possible current consumption, the ACMP should be disabled by software if not required as an
interrupt source during wait mode.
10.1.2.2 Operation in Stop Mode
The ACMP continues to operate in stop mode if enabled and compare operation remains active. If ACOPE
is enabled, comparator output operates as in the normal operating mode and comparator output is placed
onto the external pin. The MCU is brought out of stop when a compare event occurs and ACIE is enabled;
ACF flag sets accordingly.
If stop is exited with a reset, the ACMP will be put into its reset state.
10.1.2.3 Operation in Active Background Mode
When the MCU is in active background mode, the ACMP will continue to operate normally.
10.1.3 Block Diagram
The block diagram for the analog comparator module is shown in Figure 10-2.
MC9RS08KA2 Series Data Sheet, Rev. 2
82
Freescale Semiconductor