h8s-2646 Renesas Electronics Corporation., h8s-2646 Datasheet - Page 408

• Manufacturer Part Number: h8s-2646
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2600 Series
• Manufacturer: Renesas Electronics Corporation.

Section 10 16-Bit Timer Pulse Unit (TPU)
10.7
Note that the kinds of operation and contention described below occur during TPU operation.
Input Clock Restrictions: The input clock pulse width must be at least 1.5 states in the case of
single-edge detection, and at least 2.5 states 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 states, and the pulse width must be at least 2.5 states. Figure 10.48 shows the input clock
conditions in phase counting mode.
Caution on Period Setting: When counter clearing by compare match is set, TCNT is cleared in
the final state in which it matches the TGR value (the point at which the count value matched by
TCNT is updated). Consequently, the actual counter frequency is given by the following formula:
Where
Rev. 5.00 Sep 22, 2005 page 382 of 1136
REJ09B0257-0500
TCLKA
(TCLKC)
TCLKB
(TCLKD)
Notes: Phase difference and overlap
Figure 10.48 Phase Difference, Overlap, and Pulse Width in Phase Counting Mode
f =
Usage Notes
f : Counter frequency
φ : Operating frequency
N : TGR set value
Pulse width
(N + 1)
φ
Overlap
Pulse width
Phase
differ-
ence
Overlap
: 1.5 states or more
: 2.5 states or more
Phase
differ-
ence
Pulse width
Pulse width
Pulse width