HD6433044 Datasheet, PDF (615/867 Pages) Hitachi Semiconductor – Hitachi Single-Chip Microcomputer

Loop Counter Values in Programs and Watchdog Timer Overflow Interval Settings: The
values of a to h in the programs depend on the clock frequency. Table 18-14 indicates the values
for 10 MHz. Values for other frequencies can be calculated as shown below, but use the settings
in table 18-15 for the value off.
Table 18-14 Loop Counter Values in Program (10 MHz)
Variable
Clock Frequency
a (f)
b (f)
c (f)
f = 10 MHz Hexadecimal H'0019 H'0007 H'0007
d (f)
e (f)
g (f)
h (f)
H'03B3 H'0007 H'0009 H'0004
Decimal
Comments
25
7
7
947
Program tVS1 tVS2
Erase
at write at pre-write
7
9
tVS1 z
at erase
4
tVS2
Formula:
a (f) to h (f) = ^{Clock frequency f [MHz]} × {a (f = 10) to h (f = 10)}
10
Examples for 16 MHz:
a (f) = ¹⁶ × 25 =
10
40 ≈ H'0028
b (f) = ¹⁶ × 7 = 11.2 ≈ H'000C
10
c (f) = ¹⁶ × 7 = 11.2 ≈ H'000C
10
d (f) = ¹⁶ × 947 = 1515.2 ≈ H'05EC
10
e (f) = ¹⁶ × 7 = 11.2 ≈ H'000C
10
g (f) = ¹⁶ × 9 = 14.4 ≈ H'000F
10
h (f) = ¹⁶ × 4 =
10
6.4 ≈ H'0007
Table 18-15 Watchdog Timer Overflow Interval Settings
Clock Frequency
10 MHz ≤ frequency ≤ 16 MHz
2 MHz ≤ frequency < 10 MHz
1 MHz ≤ frequency < 2 MHz
Variable
f
H'A57F
H'A57E
H'A57D
Note:
The watchdog timer (WDT) set value is calculated based on the number of instructions
including write time and erase time from start to stop of WDT operation. In this program
example, therefore, no more instructions should be added between the start and stop of
WDT operation.
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