Standby Function Operation; Halt Mode - NEC 78K0S/KA1+ User Manual

13.2 Standby Function Operation

13.2.1 HALT mode

(1) HALT mode
The HALT mode is set by executing the HALT instruction.
The operating statuses in the HALT mode are shown below.
Caution Because an interrupt request signal is used to clear the standby mode, if there is an interrupt
source with the interrupt request flag set and the interrupt mask flag clear, the standby mode
is immediately cleared if set.
Setting of HALT Mode
Item
System clock
CPU
Port (latch)
16-bit timer/event counter 00
8-bit timer 80
8-bit timer Sets count clock to f
H1
Sets count clock to f
Watchdog System clock selected as
timer operating clock
"Low-speed internal oscillation
clock" selected as operating
clock
A/D converter
Serial interface UART6
Power-on-clear circuit
Low-voltage detector
External interrupt
Note "Cannot be stopped" or "Stopped by software" is selected for low-speed internal oscillator by the option byte
(for the option byte, see CHAPTER 17 OPTION BYTE).
230
CHAPTER 13 STANDBY FUNCTION
Table 13-2. Operating Statuses in HALT Mode
Low-Speed Internal
Oscillator Cannot Be
Note
Stopped
Clock supply to CPU is stopped.
Operation stops.
Holds status before HALT mode was set.
Operable
Operable
12
to f /2 Operable
XP XP
7
/2 Operable
RL
Setting prohibited
Operable (Operation
continues.)
Operable
Operable
Always operates.
Operable
Operable
User's Manual U16898EJ3V0UD
Low-Speed Internal Oscillator Can Be Stopped
When Low-Speed Internal When Low-Speed Internal
Oscillation Continues
Operable Operation stops.
Operation stops.
Operation stops.
Note
Oscillation Stops