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RESET and POWER-DOWN
To program the duration of the oscillation stabilization interval, you must make the appropriate settings to
the basic timer control register, BTCON, before entering Stop mode. Also, if you do not want to use the
basic timer watchdog function (which causes a system reset if a basic timer counter overflow occurs), you
can disable it by writing "1010B" to the upper nibble of BTCON.
MCU Initialization Sequence
The following sequence of events occurs during a Reset operation:
— All interrupts are disabled.
— The watchdog function (basic timer) is enabled.
— Ports 0–2 are set to input mode
— Peripheral control and data registers are disabled and reset to their initial values (see Table 8-1).
— The program counter is loaded with the ROM reset address, 0100H.
— When the programmed oscillation stabilization time interval has elapsed, the address stored in ROM location
0100H (and 0101H) is fetched and executed.
nRESET
LVR nRESET
Watchdog nRESET
nRESET Input
Normal Mode or
Power-Down Mode
8-2
Smart Option
(3EH.7)
Figure 8-1. Reset Block Diagram
RESET Operation
Figure 8-2. Timing for S3C9454B/F9454B After RESET
NOTE
MUX
Oscillation Stabilization Wait Time (6.55 ms/at 10 MHz)
Idle Mode
S39454B/F9454B
Internal nRESET
Operation Mode
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