upd78f0730 Renesas Electronics Corporation., upd78f0730 Datasheet - Page 86

• Manufacturer Part Number: upd78f0730
• Description: 8-bit Single-chip Microcontroller
• Manufacturer: Renesas Electronics Corporation.

(2) Processor clock control register (PCC)
86
Note The main clock mode register (MCM) is used to set the main system clock supplied to CPU clock (high-
This register is used to select the CPU clock and the division ratio.
PCC is set by a 1-bit or 8-bit memory manipulation instruction.
Reset signal generation sets PCC to 01H.
The fastest instruction can be executed in 2 clocks of the CPU clock in the
relationship between the CPU clock (f
f
f
f
f
f
Address: FFFBH
XP
XP
XP
XP
XP
Symbol
CPU Clock (f
/2
/2
/2
/2
PCC
2
3
4
speed system clock/internal high-speed oscillation clock) (see Figure 5-6).
Table 5-2. Relationship Between CPU Clock and Minimum Instruction Execution Time
Caution
Remark f
CPU
PCC2
)
7
0
0
0
0
0
1
After reset: 01H
Figure 5-3. Format of Processor Clock Control Register (PCC)
0.167
0.333
0.667
1.33
2.67
At 12 MHz Operation
Other than above
XP
Be sure to clear bits 3 and 7 to 0.
: Main system clock oscillation frequency
µ
µ
µ
µ
µ
s
s
PCC1
s
s
s
High-Speed System Clock
0
6
0
0
1
1
0
Preliminary User’s Manual U19014EJ1V0UD
R/W
CHAPTER 5 CLOCK GENERATOR
CPU
PCC0
) and the minimum instruction execution time is as shown in Table 5-2.
0
1
0
1
0
5
0
0.125
0.25
0.5
1.0
2.0
At 16 MHz Operation
Minimum Instruction Execution Time: 2/f
µ
µ
µ
µ
s
s
s
f
f
f
f
f
Setting prohibited
µ
s
XP
XP
XP
XP
XP
s
/2 (default)
/2
/2
/2
Note
2
3
4
4
0
3
0
CPU clock (f
Internal High-Speed Oscillation Clock
At 16 MHz (TYP.) Operation
PCC2
2
CPU
0.125
0.25
) selection
0.5
1.0
2.0
CPU
µ
PD78F0730. Therefore, the
µ
µ
µ
µ
µ
s (TYP.)
s (TYP.)
s (TYP.)
s (TYP.)
s (TYP.)
PCC1
1
PCC0
0
Note