
Section 4 Clock Pulse Generator (CPG)
Page 80 of 1336
R01UH0025EJ0300 Rev. 3.00
Sep 24, 2010
SH7261 Group
(7)
Frequency Control Register (FRQCR)
The frequency control register (FRQCR) has control bits assigned for the following functions:
clock output/non-output from the CKIO pin during software standby mode, the frequency
multiplication ratio of PLL circuit 1, and the frequency division ratio of the CPU clock and the
peripheral clock (P
φ).
(8)
Standby Control Register
The standby control register has bits for controlling the power-down modes. See section 27,
Power-Down Modes, for more information.
4.2
Input/Output Pins
Table 4.1 lists the clock pulse generator pins and their functions.
Table 4.1
Pin Configuration and Functions of the Clock Pulse Generator
Pin Name
Symbol
I/O
Function
(Clock Operating
Modes 0 and 2)
Function
(Clock Operating
Mode 3)
MD_CLK0
Input
Sets the clock operating
mode.
Sets the clock operating
mode.
Mode control pins
MD_CLK1
Input
Sets the clock operating
mode.
Sets the clock operating
mode.
XTAL
Output
Connected to the crystal
resonator. (Leave this pin
open when the crystal
resonator is not in use.)
Leave this pin open.
Crystal
input/output pins
(clock input pins)
EXTAL
Input
Connected to the crystal
resonator or used to input
an external clock.
Pull-up this pin.
Clock input/output
pin
CKIO
I/O
Clock output pin.
Clock input pin.