HD64F2638F20J Datasheet, PDF (438/1512 Pages) Renesas Technology Corp – Renesas 16-Bit Single-Chip Microcomputer H8S Family/H8S/2600 Series

Section 10 16-Bit Timer Pulse Unit (TPU)
H8S/2639, H8S/2638, H8S/2636,
H8S/2630, H8S/2635 Group
10.7 Usage Notes
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.
TCLKA
(TCLKC)
TCLKB
(TCLKD)
Phase
Phase
differ-
differ-
Overlap ence Overlap ence
Pulse width
Pulse width
Pulse width
Pulse width
Notes: Phase difference and overlap: 1.5 states or more
Pulse width:
2.5 states or more
Figure 10-48 Phase Difference, Overlap, and Pulse Width 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:
φ
f=
(N + 1)
Where
f : Counter frequency
φ : Operating frequency
N : TGR set value
Page 388 of 1458
REJ09B0103-0800 Rev. 8.00
May 28, 2010