Table of Contents
Advertisement
Functional description
25.7.4.4.2 Stop mode operation
This module is disabled in Stop mode. All internal analog circuits are switched off.
25.7.4.4.3 Background debug mode operation
When the microcontroller is in active background debug mode, the GCMP continues to
operate normally.
25.7.4.5 Startup and operation
A typical startup sequence is as follows.
The time required to stabilize COUT will be the power-on delay of the comparators plus
the largest propagation delay from a selected analog source through the analog
comparator, windowing function and filter. Power on delay of the comparators are
available from data sheets. The windowing function has a maximum of 1 bus clock
period delay. Filter delay is specified in
Low pass
filter.
During operation, the propagation delay of the selected data paths must always be
considered. It can take many bus clock cycles for COUT and the CFR/CFF status bits to
reflect an input change or a configuration change to one of the components involved in
the data path.
When programmed for filtering modes, COUT will initially be equal to zero until
sufficient clock cycles have elapsed to fill all stages of the filter. This occurs even if
COUTA is at a logic one.
25.7.4.6 Low pass filter
The low-pass filter operates on the unfiltered and unsynchronized and optionally inverted
comparator output COUTA and generates the filtered and synchronized output COUT.
Both COUTA and COUT can be configured as module outputs and are used for different
purposes within the system.
Synchronization and edge detection are always used to determine status register bit
values. They also apply to COUT for all sampling and windowed modes. Filtering can be
performed using an internal timebase defined by FPR[FILT_PER], or using an external
SAMPLE input to determine sample time.
MC9S08SU16 Reference Manual, Rev. 5, 4/2017
478
NXP Semiconductors
Advertisement
Table of Contents
