HD6413008F RENESAS [Renesas Technology Corp], HD6413008F Datasheet - Page 514

• Manufacturer Part Number: HD6413008F
• Description: Renesas 16-Bit Single-Chip Microcomputer H8 Family/H8/300H Series
• Manufacturer: RENESAS [Renesas Technology Corp]

18. Power-Down State
function and becomes a port pin. If its port DDR bit is set to 1, the pin becomes a data output pin,
and its output may collide with external SCI transmit data. Data collision should be prevented by
clearing the port DDR bit to 0 or taking other appropriate action.
Register Resetting: When an on-chip supporting module is halted by the module standby
function, all its registers are initialized. To restart the module, after its MSTCR bit is cleared to 0,
its registers must be set up again. It is not possible to write to the registers while the MSTCR bit is
set to 1.
18.7
Output of the system clock (φ) can be controlled by the PSTOP bit in MSTCRH. When the
PSTOP bit is set to 1, output of the system clock halts and the φ pin is placed in the high-
impedance state. Figure 18.3 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 18.4 indicates
the state of the φ pin in various operating states.
Table 18.4 φ Pin State in Various Operating States
Operating State
Hardware standby
Software standby
Sleep mode
Normal operation
Rev.4.00 Aug. 20, 2007 Page 470 of 638
REJ09B0395-0400
φ pin
System Clock Output Disabling Function
MSTCRH write cycle
Figure 18.3 Starting and Stopping of System Clock Output
T1
(PSTOP = 1)
T2
T3
PSTOP = 0
High impedance
Always high
System clock output
System clock output
High impedance
MSTCRH write cycle
PSTOP = 1
High impedance
High impedance
High impedance
High impedance
T1
(PSTOP = 0)
T2
T3