NEC uPD78P078 - Manual (Page 169)

169
CHAPTER 7 CLOCK GENERATOR
The fastest instruction of the
µ
PD78078 and 78078Y Subseries can be executed in two clocks of the CPU clock.
The relationship between the CPU clock (f
CPU
) and the minimum instruction execution time is 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
f
X
= 5.0 MHz, f
XT
= 32.768 kHz
f X : Main system clock oscillation frequency
f XT : Subsystem clock oscillation frequency