mcf51jf128 Freescale Semiconductor, Inc, mcf51jf128 Datasheet - Page 699

• Manufacturer Part Number: mcf51jf128
• Description: Mcf51jf128 Reference Manual
• Manufacturer: Freescale Semiconductor, Inc

Chapter 30 Comparator (CMP)
30.8.2.2 Stop Mode Operation
Subject to platform-specific clock restrictions, the MCU is brought out of stop when a
compare event occurs and the corresponding interrupt is enabled. Similarly, if CR1[OPE]
is enabled, the comparator output operates as in the normal operating mode and
comparator output is placed onto the external pin. In stop modes, the comparator can be
operational in both high speed (HS) comparison mode (CR1[PMODE] = 1) and low
speed (LS) comparison mode (CR1[PMODE] = 0), but it is recommended to use the low
speed mode to minimize power consumption.
If stop is exited with a reset, all comparator registers are put into their reset state.
30.8.2.3 Low-Leakage Mode Operation
During low-leakage modes, the CMP module is partially functional and is limited to low
speed mode (regardless of the CR1[PMODE] bit setting. Windowed, sampled, and
filtered modes are not supported. The CMP output pin is latched and does not reflect the
compare output state.
The positive- and negative-input voltage can be from external pins or the DAC output.
The MCU can be brought out of the low-leakage mode if a compare event occurs and the
CMP interrupt is enabled. After wake-up from low-leakage modes, the CMP module is in
the reset state except for the SCR[CFF] and SCR[CFR] flags.
30.8.2.4 Background Debug Mode Operation
When the microcontroller is in active background debug mode, the CMP continues to
operate normally.
30.8.3 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.
MCF51JF128 Reference Manual, Rev. 2, 03/2011
Preliminary
Freescale Semiconductor, Inc.
699