Standby Function Operation; Halt Mode - NEC UPD789426 Series User Manual

15.2 Standby Function Operation

15.2.1 HALT mode

(1) HALT mode
The HALT mode is set by executing the HALT instruction.
The operation status in the HALT mode is shown in the following table.
Item HALT Mode Operation Status While The Main
System Clock Is Running
While the subsystem
clock is running
Main system clock Oscillation enabled
CPU Operation stopped
Port (output latch) Remains in the state existing before the selection of HALT mode.
16-bit timer Operation enabled
8-bit timer TM50 Operation enabled
TM60
Watch timer Operation enabled
Watchdog timer Operation enabled
Serial interface Operation enabled
A/D converter Operation stopped
LCD controller/driver Operation enabled
External interrupt Operation enabled
Notes 1. Operation is enabled only when input signal from timer 60 (timer 60 operation is enabled) is selected as
the count clock.
2. Operation is enabled when TMI60 is selected as the count clock.
3. Operation is enabled while the main system clock is selected.
4. Operation is enabled while the subsystem clock is selected.
5. Operation is enabled only when external clock is selected.
6. Maskable interrupt that is not masked
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CHAPTER 15 STANDBY FUNCTION
Table 15-1. HALT Mode Operating Status
While the subsystem
clock is not running
Operation enabled
Operation enabled
Note 6
User's Manual U15075EJ2V1UD
HALT Mode Operation Status While The
Subsystem Clock Is Running
While the main system
clock is running
Note 3
Operation enabled
Operation stopped
Note 3
Operation enabled
While the main system
clock is not running
Oscillation stopped
Operation stopped
Note 1
Operation enabled
Note 2
Operation enabled
Note 4
Operation enabled
Note 5
Operation stopped
Note 4
Operation enabled