Samsung S3F84B8 - STOP - Stop Operation

S3F84B8_UM_REV 1.00 6 INSTRUCTION SET
6-79
6.3.67 STOP — STOP OPERATION
STOP
Opera
tion:
The STOP instruction stops both the CPU clock and system clock and causes the microcontroller
to enter the Stop mode. In the Stop mode, the contents of on-chip CPU registers, peripheral
registers, and I/O port control and data registers are retained. Stop mode can be released by an
external reset operation or by external interrupts. For the reset operation, the nRESET pin must
be held to Low level until the required oscillation stabilization interval has elapsed.
In application programs, a STOP instruction must be immediately followed by at least three NOP
instructions. This ensures an adequate time interval for the clock to stabilize before the next
instruction is executed. If three or more NOP instructions are not used after STOP instruction,
leakage current will not flow because of floating state in the internal bus.
Flags: No flags are affected.
Format:
Bytes Cycles Opcode
(Hex)
Addr Mode
dst src
opc 1 4 7F – –
Example: The statement
STOP ; halts all microcontroller operations
NOP
NOP
NOP