NEC uPD78056Y User Manual
Page 163

163
CHAPTER 7 CLOCK GENERATOR
The fastest instruction of the
µ
PD78054 and 78054Y Subseries is executed with two clocks of the CPU clock.
Therefore, relationships between the CPU clock (f
CPU
) and the minimum instruction execution time are as shown in
Table 7-2.
Table 7-2. Relationship between CPU Clock and Minimum Instruction Execution Time
CPU Clock (f
CPU
)
Minimum Instruction Execution Time: 2/f
CPU
f
X
0.4
µ
s
f
X
/2
0.8
µ
s
f
X
/2
2
1.6
µ
s
f
X
/2
3
3.2
µ
s
f
X
/2
4
6.4
µ
s
f
X
/2
5
12.8
µ
s
f
XT
/2
122
µ
s
Remarks 1. f
X
= 5.0 MHz, f
XT
= 32.768 kHz
2. f
X
: Main system clock oscillation frequency
3. f
XT
: Subsystem clock oscillation frequency
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