Samsung 8-Bit CMOS Microcontroller, S3C9228/P9228 user manual Stop Control Register Stpcon

S3C9228/P9228 CLOCK CIRCUITS

STOP CONTROL REGISTER (STPCON)

The STOP control register, STPCON, is located in address E0H. It is read/write addressable and has the following functions:

—Enable/Disable STOP instruction

After a reset, the STOP instruction is disabled, because the value of STPCON is "other values". If necessary, you can use the STOP instruction by setting the value of STPCON to "10100101B".

Stop Control Register (STPCON)

E0H, R/W

MSB

.7

.6

.5

.4

.3

.2

.1

.0

LSB

STOP control bits:

10100101 = Enable STOP instruction Other values = Disable STOP instruction

Figure 7-9. STOP Control Register (STPCON)

+PROGRAMMING TIP — How to Use Stop Instruction

This example shows how to go STOP mode when a main clock is selected as the system clock.

LD	STOPCON,#1010010B	;	Enable STOP instruction
STOP		;	Enter STOP mode
NOP
NOP
NOP		;	Release STOP mode
LD	STOPCON,#00000000B	;	Disable STOP instruction

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