NXP Semiconductors Kinetis KE1xZ256, Reference Manual

Page: 818 / 1325

This mode needs some trigger events to work. The trigger events include the operation
clock and a trigger start signal which can be provided by other module (e.g. LPTMR).
Round robin mode works as follows:
1. The trigger start signal will enable the comparator and internal DAC in the
initialization delay period;
2. The comparator will then compare the multiple input channels with the reference
input channel in turn under the operation clock until all input channels complete
comparison;
3. If current comparison result is different with the pre-set state or the previous
comparison result and round robin interrupt is enabled, an interrupt will generate to
bring the MCU out of STOP mode.
Round robin clock
MCU STOP
Trigger event
Round robin start
Enable Comparator /
Internal DAC
Input channel state
Sample channels
comparison result
Channels result
Channel 1 Channel 1/2
Channel 1 Channel 2 Channel 3
Channel 1/2/3
Initialization delay
Possible interrupt
MCU Wake Up
Detect comparison result changing
The code snippet to enable the round robin mode is:
/* Set the positive port input from DAC and negative port input from minus mux input */
/* Plus mux input must be different from minus mux input even though they aren't functional
in round robin mode. */
CMPx_C1 = ((CMPx_C1 & (~(CMP_C1_INPSEL_MASK | CMP_C1_INNSEL_MASK | CMP_C1_PSEL_MASK |
CMP_C1_MSEL_MASK)))
| (CMP_C1_INPSEL(0) | CMP_C1_INNSEL(1) | CMP_C1_PSEL(0) | CMP_C1_MSEL(1)));
/* Set following round robin attribute:
positive port as fixed port.
All channel0~7 as the round robin checker channel in non-fixed port.
The comparison result is sampled as soon as the active channel is scanned in one round-robin
clock.
The initialization delay modulus is set to 64.
Enable round robin mode.
Usage Guide
Kinetis KE1xZ256 Sub-Family Reference Manual, Rev. 3, 07/2018
818 NXP Semiconductors