HD6433044 Hitachi Semiconductor, HD6433044 Datasheet - Page 662

• Manufacturer Part Number: HD6433044
• Description: (HD64 Series) Hitachi Single-Chip Microcomputer
• Manufacturer: Hitachi Semiconductor

20.7 System Clock Output Disabling Function
Output of the system clock (ø) can be controlled by the PSTOP bit in MSTCR. When the PSTOP
bit is set to 1, output of the system clock halts and the ø pin is placed in the high-impedance state.
Figure 20-3 shows the timing of the stopping and starting of system clock output. When the
PSTOP bit is cleared to 0, output of the system clock is enabled. Table 20-4 indicates the state of
the ø pin in various operating states.
Table 20-4 ø Pin State in Various Operating States
Operating State
Hardware standby
Software standby
Sleep mode
Normal operation
ø pin
MSTCR write cycle
T1
(PSTOP = 1)
Figure 20-3 Starting and Stopping of System Clock Output
T2
T3
PSTOP = 0
High impedance
Always high
System clock output
System clock output
High impedance
653
PSTOP = 1
High impedance
High impedance
High impedance
High impedance
MSTCR write cycle
T1
(PSTOP = 0)
T2
T3