HD6432646 Hitachi, HD6432646 Datasheet - Page 778

• Manufacturer Part Number: HD6432646
• Description: (HD64F264x Series) 16-Bit Microcomputer
• Manufacturer: Hitachi

22.6.5
I/O Port Status: In software standby mode, I/O port states are retained. If the OPE bit is set to 1,
the address bus and bus control signal output is also retained. Therefore, there is no reduction in
current dissipation for the output current when a high-level signal is output.
Current Dissipation during Oscillation Stabilization Wait Period: Current dissipation
increases during the oscillation stabilization wait period.
Write Data Buffer Function: The write data buffer function and software standby mode cannot
be used at the same time. When the write data buffer function is used, the WDBE bit in BCRL
should be cleared to 0 to cancel the write data buffer function before entering software standby
mode. Also check that external writes have finished, by reading external addresses, etc., before
executing a SLEEP instruction to enter software standby mode. See section 7.7, Write Data Buffer
Function, for details of the write data buffer function.
744
Oscillator
ø
NMI
NMIEG
SSBY
Usage Notes
Figure 22-3 Software Standby Mode Application Example
NMI exception
handling
NMIEG=1
SSBY=1
SLEEP instruction
Software standby mode
(power-down mode)
stabilization
Oscillation
time t
OSC2
NMI exception
handling