HD6433640 HITACHI [Hitachi Semiconductor], HD6433640 Datasheet - Page 157

• Manufacturer Part Number: HD6433640
• Description: H8/3644 Series Hardware Manual
• Manufacturer: HITACHI [Hitachi Semiconductor]

Formula:
If an operating frequency other than those shown in table 6.12 is used, the values can be calculated
using the formula shown below. The calculation is based on an operating frequency (ø) of 5 MHz.
For a (ø) and d (ø), after decimal calculation, round down the first decimal place and convert to
hexadecimal so that a (ø) and d (ø) are 15.8 s or less and 6.25 ms or less, respectively.
For b (ø) and c (ø), after decimal calculation, round up the first decimal place and convert to
hexadecimal so that b (ø) and c (ø) are 4 s or more and 2 s or more, respectively.
Examples:
Sample calculations when executing a program in on-chip memory (RAM) at an operating
frequency of 6 MHz
Table 6.13 Watchdog Timer Overflow Interval Settings (Set Value of #e for Operating
Variable
e (ø)
148
a (ø) =
b (ø) =
c (ø) =
d (ø) =
a (ø) to d (ø) =
Frequencies)
6
5
6
5
6
5
6
5
f
ø = 8 MHz
H'9B
1953 = 2343.6
OSC
Operating frequency ø [MHz]
2
4
9 = 10.8
= 16 MHz
=
=
2.4
4.8
5
2343 = H'0927
10 = H'000A
f
ø = 5 MHz
H'DF
3
5
OSC
= H'03
= H'05
= 10 MHz
Oscillation Frequency
Operating Frequency
a (ø = 5) to d (ø = 5)
f
ø = 4 MHz
H'E5
OSC
= 8 MHz
f
ø = 1 MHz
H'F7
OSC
= 2 MHz