R01UH0823EJ0100 Rev.1.00
Page 596 of 1823
Jul 31, 2019
RX23W Group
23. Multi-Function Timer Pulse Unit 2 (MTU2a)
23.6
Usage Notes
23.6.1
Module Clock Stop Mode Setting
MTU operation can be disabled or enabled using the module stop control register. MTU operation is stopped with the
initial setting. Register access is enabled by releasing the module clock stop mode. For details, refer to
23.6.2
Count Clock Restrictions
The count clock source pulse width must be at least 1.5 PCLK cycles for single-edge detection, and at least 2.5 PCLK
cycles for both-edge detection. The MTU will not operate properly at narrower pulse widths.
In phase counting mode, the phase difference and overlap between the two input clocks must be at least 1.5 PCLK
cycles, and the pulse width must be at least 2.5 PCLK cycles.
shows the input clock conditions in phase
counting mode.
Figure 23.96
Phase Difference, Overlap, and Pulse Width in Phase Counting Mode
23.6.3
Notes on Cycle Setting
When counter clearing on compare match is set, the TCNT counter is cleared in the final state in which it matches the
TGR register value (the point at which the TCNT counter updates the matched count value). Consequently, the actual
counter frequency is given by the following formula:
MTU0 to MTU4
f: Counter frequency
CNTCLK: The count clock frequency set by the TCR.TPSC[2:0] bits
N: The TGR register setting
Phase
difference
Overlap
Overlap
MTCLKA
(MTCLKC)
MTCLKB
(MTCLKD)
Pulse width
Pulse width
Pulse width
Pulse width
Phase
difference
Note:
Phase difference and overlap: At least 1.5 PCLK cycles
Pulse width: At least 2.5 PCLK cycles
f
CNTCLK
N 1
+
-------------------------
=