Samsung S3C9228/P9228 Microcassette Recorder User Manual


 
S3C9228/P9228 CLOCK CIRCUITS
7-7
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
.7 .6 .5 .4 .3 .2 .1 .0MSB 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