M30621ECGP MITSUBISHI [Mitsubishi Electric Semiconductor], M30621ECGP Datasheet - Page 26

• Manufacturer Part Number: M30621ECGP
• Description: SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
• Manufacturer: MITSUBISHI [Mitsubishi Electric Semiconductor]

Clock Generating Circuit
26
Clock Generating Circuit
Example of oscillator circuit
Table 1.9.1. Main clock and sub clock generating circuits
Figure 1.9.2. Examples of sub clock
Figure 1.9.1. Examples of main clock
The clock generating circuit contains two oscillator circuits that supply the operating clock sources to the
CPU and internal peripheral units.
Use of clock
Usable oscillator
Pins to connect oscillator
Oscillation stop/restart function
Oscillator status immediately after reset
Other
Figure 1.9.1 shows some examples of the main clock circuit, one using an oscillator connected to the
circuit, and the other one using an externally derived clock for input. Figure 1.9.2 shows some examples of
sub clock circuits, one using an oscillator connected to the circuit, and the other one using an externally
derived clock for input. Circuit constants in Figures 1.9.1 and 1.9.2 vary with each oscillator used. Use the
values recommended by the manufacturer of your oscillator.
Note: Insert a damping resistor if required. The resistance will vary depending on the oscillator and the oscillation drive
Note: Insert a damping resistor if required. The resistance will vary depending on the oscillator and the oscillation drive
X
(Built-in feedback resistor)
X
(Built-in feedback resistor)
CIN
IN
capacity setting. Use the value recommended by the maker of the oscillator.
When the oscillation drive capacity is set to low, check that oscillation is stable. Also, if the oscillator manufacturer's
data sheet specifies that a feedback resistor be added external to the chip, insert a feedback resistor between X
and X
capacity setting. Use the value recommended by the maker of the oscillator.
When the oscillation drive capacity is set to low, check that oscillation is stable. Also, if the oscillator manufacturer's
data sheet specifies that a feedback resistor be added external to the chip, insert a feedback resistor between X
and X
Microcomputer
Microcomputer
C
C
IN
CIN
COUT
OUT
following the instruction.
following the instruction.
X
COUT
X
OUT
R
(Note)
C
(Note)
R
C
Cd
COUT
d
OUT
• CPU’s operating clock source
• Internal peripheral units’
Ceramic or crystal oscillator
X
Available
Oscillating
Externally derived clock can be input
operating clock source
IN
Main clock generating circuit
, X
OUT
Vcc
Vss
Vcc
Vss
Externally derived clock
(Built-in feedback resistor)
Externally derived clock
(Built-in feedback resistor)
X
X
IN
CIN
Microcomputer
Microcomputer
SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER
• CPU’s operating clock source
• Timer A/B’s count clock
Crystal oscillator
X
Available
Stopped
CIN
Sub clock generating circuit
source
, X
X
Open
X
Open
COUT
OUT
M16C / 62 Group (80-pin)
COUT
CIN
IN
Mitsubishi microcomputers