Register Configuration; Register Descriptions; System Clock Control Register (Sckcr) - Hitachi H8S/2646 Hardware Manual

21.1.2

Register Configuration

The clock pulse generator is controlled by SCKCR and LPWRCR. Table 21-1 shows the register
configuration.
Table 21-1 Clock Pulse Generator Register
Name
System clock control register
Low-power control register
Note:* Lower 16 bits of the address.
21.2

Register Descriptions

21.2.1

System Clock Control Register (SCKCR)

Bit : 7
PSTOP
Initial value : 0
R/W : R/W
SCKCR is an 8-bit readable/writable register that performs ø clock output control and medium-
speed mode control, selection of operation when the PLL circuit frequency multiplication factor is
changed, and medium-speed mode control.
SCKCR is initialized to H'00 by a reset and in hardware standby mode. It is not initialized in
software standby mode.
Bit 7—ø Clock Output Disable (PSTOP): Controls ø output.
Bit 7
High Speed Mode,
Medium Speed Mode,
Sub-Active Mode
PSTOP
0 ø output (initial value)
1 Fixed high
Bits 6 to 4—Reserved: These bits are always read as 0 and cannot be modified.
716
Abbreviation
SCKCR
LPWRCR
6 5 4
— — —
0 0 0
— — —
Description
Sleep Mode,
Sub-Sleep Mode
ø output
Fixed high
R/W Initial Value
R/W H'00
R/W H'00
3 2
STCS SCK2
0 0
R/W R/W
Software Standby
Mode, Watch Mode,
and Direct Transition
Fixed high
Fixed high
Address*
H'FDE6
H'FDEC
1 0
SCK1 SCK0
0 0
R/W R/W
Hardware
Standby Mode
High impedance
High impedance