upd78f0103hmca1-5a4-a Renesas Electronics Corporation., upd78f0103hmca1-5a4-a Datasheet - Page 85

• Manufacturer Part Number: upd78f0103hmca1-5a4-a
• Description: 8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

<R>
(2) Internal oscillation mode register (RCM)
The fastest instruction can be executed in 2 clocks of the CPU clock in the 78K0/KB1+.
relationship between the CPU clock (f
Notes 1. The main clock mode register (MCM) is used to set the CPU clock (high-speed system clock/internal
This register sets the operation mode of the internal oscillator.
This register is valid when “Can be stopped by software” is set for the internal oscillator by the option byte, and
the high-speed system clock is input to the CPU clock. If “Cannot be stopped” is selected for the internal
oscillator by the option byte, settings for this register are invalid.
RCM can be set by a 1-bit or 8-bit memory manipulation instruction.
RESET input clears this register to 00H.
Address: FFA0H
f
f
f
f
f
X
X
X
X
X
/2
/2
/2
/2
Symbol
RCM
2
3
4
CPU Clock (f
2. When crystal/ceramic oscillation is used
3. Setting is prohibited for the (A1) grade products.
Table 5-2. Relationship Between CPU Clock and Minimum Instruction Execution Time
oscillation clock) (see Figure 5-4).
Caution Make sure that bit 1 (MCS) of the main clock mode register (MCM) is 1 before setting
RSTOP
CPU
7
0
0
1
)
After reset: 00H
Figure 5-3. Format of Internal Oscillation Mode Register (RCM)
RSTOP.
0.2
0.4
0.8
1.6
3.2
Internal oscillator oscillating
Internal oscillator stopped
At 10 MHz Operation
µ
µ
µ
µ
µ
s
s
s
s
s
6
0
R/W
CHAPTER 5 CLOCK GENERATOR
CPU
High-Speed System Clock
) and minimum instruction execution time is as shown in the Table 5-2.
User’s Manual U16846EJ3V0UD
5
0
Note 2
Minimum Instruction Execution Time: 2/f
Internal oscillator oscillating/stopped
0.125
0.25
0.5
1.0
2.0
4
0
At 16 MHz Operation
µ
µ
µ
µ
s
s
s
µ
s
s
Note 1
3
0
Note 2
2
0
8.3
16.6
Setting prohibited
Setting prohibited
Setting prohibited
At 240 kHz (TYP.) Operation
Internal Oscillation Clock
CPU
µ
s (TYP.)
µ
s (TYP.)
1
0
Note 3
Therefore, the
RSTOP
<0>
Note 1
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