
S3C3410X RISC MICROPROCESSOR
POWER MANAGEMENT
15-3
STOP MODE
Entering STOP Mode
STOP mode is invoked by the setting SYSCON[0] to "1". In STOP mode, the operation of the CPU and all
peripherals should be halted. That is, the on-chip main oscillator stops and the supply current is reduced to less
than 1uA. All system functions stop when the clock "freezes", but data stored in the internal register file is
retained. STOP mode can be released by two ways: by a reset or by an external interrupt or alarm interrupt.
NOTE
Do not use STOP mode if you are using an external clock source because Xin input must be restricted
internal to VSS to reduce current leakage. Also, do not use STOP mode if program control execute in
DRAM memory because of DRAM leakage current. Therefore, please confirm status before the STOP
mode: STOP command in located Non-DRAM memory.
Wake-Up from STOP Mode
The S3C3410X can be escaped from STOP mode by external interrupt or by a reset.
Using
RESET
RESET to Release STOP Mode: The STOP mode should be released when the RESET signal is
released. All system and peripheral control registers are reset to have their default hardware values and the
contents of data registers should be retained. A reset operation automatically selects a slow clock(MCLK/16)
because SYSCON[5:3] are cleared to "000b". After the programmed oscillation stabilization interval has elapsed,
the CPU starts the system initialization routine by fetching the program instruction stored in location 0x0.
Using an External Interrupt to Release STOP Mode: External interrupts and alarm interrupt can be used to
release STOP mode. Which interrupt you can use to release STOP mode in a given situation depends on the
current microcontroller's operating mode. The external interrupts of EINT0 - EINT11 and alarm interrupt in the
S3C3410X can be used to release STOP mode :
Please note the following conditions for STOP mode release:
If user want to release STOP mode by using an external interrupt or alarm interrupt, the current values in
system and peripheral control registers should be unchanged. User can also program the duration of the
oscillation stabilization interval. To do this, user should make the appropriate control and clock setting before
entering STOP mode.
When the STOP mode is released by external interrupt or alarm interrupt, the SYSCON[5:3] setting remains
unchanged and the selected clock value is used.
The external interrupt should be serviced when the STOP mode release interrupt occurs. After interrupt
service routine, the program sequence should be return to the instruction after the instruction for STOP mode
entrance.