R01UH0823EJ0100 Rev.1.00
Page 716 of 1823
Jul 31, 2019
RX23W Group
25. 16-Bit Timer Pulse Unit (TPUa)
25.9
Usage Notes
25.9.1
Module Stop Function Setting
Operation of the TPU can be disabled or enabled using the module stop control register. The TPU does not operate with
the initial setting. Register access is enabled by releasing the module stop state. For details, see
.
25.9.2
Input Clock Restrictions
The input clock pulse width must be at least 1.5 PCLK cycles in the case of single-edge detection, and at least 2.5 PCLK
cycles in the case of both-edge detection. The TPU will not operate properly with a narrower pulse width.
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 25.43
Phase Difference, Overlap, and Pulse Width in Phase Counting Mode
25.9.3
Notes on Cycle Setting
When counter clearing by compare match is set, TPUm.TCNT is cleared in the final state in which it matches the
TPUm.TGRy value (the point at which the count value matched by TCNT is updated). Consequently, the actual counter
frequency is given by the following formula:
f:
Counter frequency
f
TCNT_CLK
:
Count clock frequency
N:
TGRy set value
Overlap
Phase
difference
TCLKA (TCLKC)
TCLKB (TCLKD)
Pulse width
Pulse width
Pulse width
Pulse width
Note:
Overlap
Phase
difference
Phase difference, Overlap:
Pulse width:
At least 1.5 PCLK cycles
At least 2.5 PCLK cycles
f =
f
TCNT_CLK
(N + 1)