HD64F3687GHV Datasheet, PDF (121/566 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

Section 5 Clock Pulse Generator
φRC
FTIOA0 input
capture input
Timer Z
TCNT
M−1 M M+1
GRA_0
N
M
t_A (µs)
M+α
M+α
GRC_0
N
Capture 1
M
Capture 2
Figure 5.10 Timing Chart of Trimming of On-Chip Oscillator Frequency
The on-chip oscillator frequency is gained by the expression below. Since the input-capture input
is
sampled
by
the
φ
RC
clock,
the
calculated
result
may
include
a
sampling
error
of
±1
cycle
of
the
φ
RC
clock.
(M + α) − M
φRC =
(MHz)
t_A
φRC: Frequency of on-chip oscillator (MHz)
t_A: Period of reference clock (µs)
M: Timer Z counter value
Rev. 3.00 Sep. 10, 2007 Page 87 of 528
REJ09B0216-0300