M16C6KA_15 Datasheet, PDF (31/270 Pages) Renesas Technology Corp – SINGLE-CHIP 16-BIT CMOS MICROCOMPUTER Description

M16C/6KA Group
Clock Generating Circuit
Clock Generating Circuit
The clock generating circuit contains two oscillator circuits that supply the operating clock sources to the
CPU and internal peripheral units.
Table.WA-1 Main clock generating circuits
Main clock generating circuit
Use of clock
• CPU’s operating clock source
• Internal peripheral units’
operating clock source
Usable oscillator
Ceramic oscillator
Pins to connect oscillator
XIN, XOUT
Oscillation stop/restart function
Available
Oscillator status immediately after reset
Oscillating
Other
Externally derived clock can be input
Example of oscillator circuit
Fig.WA-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. Circuit constants in Fig.WA-1 vary with oscilla-
tor used. Use the values recommended by the manufacturer of your oscillator.
Microcomputer
(Built-in feedback resistor)
XIN
XOUT
(Note)
Rd
CIN
COUT
Microcomputer
(Built-in feedback resistor)
XIN
XOUT
Open
Externally derived clock
Vcc
Vss
Note: Insert a damping resistor if required. The resistance will vary depending on the oscillator and the oscillation drive
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.
Apply the feedback register between XIN and XOUT if required by oscillator maker.
Fig.WA-1 Examples of main clock
Rev.1.00 Jul 16, 2004 page 29 of 266
REJ03B0100-0100Z