MC9S08SH32 Datasheet, PDF (115/328 Pages) Freescale Semiconductor, Inc – Microcontrollers

Chapter 8 Analog Comparator (S08ACMPV3)
8.2 Features
The ACMP has the following features:
• Full rail to rail supply operation.
• 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.
• Can operate in stop3 mode
8.3 Modes of Operation
This section defines the ACMP operation in wait, stop and background debug modes.
8.3.0.1 ACMP in Wait Mode
The ACMP continues to run 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, ACIE is enabled. For
lowest possible current consumption, the ACMP should be disabled by software if not required as an
interrupt source during wait mode.
8.3.0.2 ACMP in Stop Modes
8.3.0.2.1 Stop3 Mode Operation
The ACMP continues to operate in Stop3 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.
8.3.0.2.2 Stop2 and Stop1 Mode Operation
During either Stop2 and Stop1 mode, the ACMP module will be fully powered down. Upon wake-up from
Stop2 or Stop1 mode, the ACMP module will be in the reset state.
8.3.0.3 ACMP in Active Background Mode
When the microcontroller is in active background mode, the ACMP will continue to operate normally.
8.4 Block Diagram
The block diagram for the Analog Comparator module is shown Figure 8-2.
MC9S08SH32 Series Data Sheet, Rev. 2
Freescale Semiconductor
115
PRELIMINARY