upd78f0103 Renesas Electronics Corporation., upd78f0103 Datasheet - Page 92

• Manufacturer Part Number: upd78f0103
• Description: 8-bit Single-chip Microcontrollers
• Manufacturer: Renesas Electronics Corporation.

(2) Ring-OSC mode register (RCM)
92
The fastest instruction can be executed in 2 clocks of the CPU clock in the 78K0/KB1. Therefore, the relationship
between the CPU clock (f
This register sets the operation mode of Ring-OSC.
This register is valid when “Can be stopped by software” is set for Ring-OSC by a mask option, and the X1 input
clock is input to the CPU clock. If “Cannot be stopped” is selected for Ring-OSC 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.
Address: FFA0H
Symbol
RCM
Notes 1. The main clock mode register (MCM) is used to set the CPU clock (X1 input clock/Ring-OSC
Table 5-2. Relationship Between CPU Clock and Minimum Instruction Execution Time
f
f
f
f
f
X
X
X
X
X
/2
/2
/2
/2
CPU Clock (f
2
3
4
Caution Make sure that bit 1 (MCS) of the main clock mode register (MCM) is 1 before setting
RSTOP
2. Expanded-specification products of standard products and (A) grade products only
3. The setting of (A1) grade products and (A2) grade products is prohibited.
7
0
0
1
clock) (see Figure 5-4).
After reset: 00H
CPU
RSTOP.
)
Ring-OSC oscillating
Ring-OSC stopped
CPU
Figure 5-3. Format of Ring-OSC Mode Register (RCM)
Note 1
) and minimum instruction execution time is as shown in the Table 5-2.
6
0
0.2
0.4
0.8
1.6
3.2
At 10 MHz
Operation
µ
µ
µ
µ
µ
R/W
CHAPTER 5 CLOCK GENERATOR
s
s
s
s
s
User’s Manual U15836EJ5V0UD
5
0
X1 Input Clock
Minimum Instruction Execution Time: 2/f
0.166
0.333
0.666
1.333
2.666
Operation
At 12 MHz
Ring-OSC oscillating/stopped
4
0
µ
µ
µ
µ
µ
s
s
s
s
s
Note 2
3
0
8.3
16.6
Setting prohibited
Setting prohibited
Setting prohibited
(at 240 kHz (TYP.) Operation)
µ
µ
s (TYP.)
s (TYP.)
Ring-OSC Clock
2
0
Note 3
CPU
1
0
RSTOP
<0>