upd78f0124m6gba1-8et Renesas Electronics Corporation., upd78f0124m6gba1-8et Datasheet - Page 107

• Manufacturer Part Number: upd78f0124m6gba1-8et
• Description: 8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

(2) Internal oscillation mode register (RCM)
Notes 1.
The fastest instruction can be executed in 2 clocks of the CPU clock in the 78K0/KD1. Therefore, the relationship
between the CPU clock (f
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 a mask option, and the
X1 input clock or subsystem clock is selected as the CPU clock. If “Cannot be stopped” is selected for the
internal oscillator by a mask option, 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.
f
f
f
f
f
f
Address: FFA0H
X
X
X
X
X
XT
/2
/2
/2
/2
CPU Clock (f
/2
Symbol
2
3
4
RCM
2.
3.
Table 5-2. Relationship Between CPU Clock and Minimum Instruction Execution Time
The main clock mode register (MCM) is used to set the CPU clock (X1 input clock/internal oscillation
clock) (see Figure 5-4).
Expanded-specification products of standard products and (A) grade products only
Setting is prohibited for the (A1) and (A2) grade products.
Caution Make sure that bit 1 (MCS) of the main clock mode register (MCM) is 1 before setting
CPU
RSTOP
)
7
0
0
1
After reset: 00H
Figure 5-3. Format of Internal Oscillation Mode Register (RCM)
0.2
0.4
0.8
1.6
3.2
RSTOP.
At 10 MHz
Operation
µ
µ
µ
µ
µ
Internal oscillator oscillating
Internal oscillator stopped
CPU
s
s
s
s
s
X1 Input Clock
) and the minimum instruction execution time is as shown in Table 5-2.
6
0
−
0.166
0.333
0.666
1.333
2.666
R/W
Operation
CHAPTER 5 CLOCK GENERATOR
At 12 MHz
Note 1
User’s Manual U16315EJ3V1UD
5
0
µ
µ
µ
µ
µ
s
s
s
s
s
Minimum Instruction Execution Time: 2/f
Note 2
Internal oscillator oscillating/stopped
8.3
16.6
Setting prohibited
Setting prohibited
Setting prohibited
(at 240 kHz (TYP.) Operation)
Internal Oscillation Clock
4
0
µ
µ
s (TYP.)
s (TYP.)
Note 3
−
3
0
Note 1
2
0
122.1
CPU
(at 32.768 kHz Operation)
µ
Subsystem Clock
s
1
0
−
−
−
−
−
RSTOP
<0>
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