RESET and POWER-DOWN

S3C84E5/C84E9/P84E9

 

 

How to Enter into Stop Mode

There are two steps to enter into Stop mode:

1.Handling OSCCON register.

2.Handling STPCON register then writing Stop instruction (keep the order).

IDLE MODE

Idle mode is invoked by the instruction IDLE (opcode 6FH). In idle mode, CPU operations are halted while some peripherals remain active. During idle mode, the internal clock signal is gated away from the CPU, but all peripherals timers remain active. Port pins retain the mode (input or output) they had at the time idle mode was entered.

There are two ways to release idle mode:

1.Execute a reset. All system and peripheral control registers are reset to their default values and the contents of all data registers are retained. The reset automatically selects the slow clock fxx/16 because CLKCON.4 and CLKCON.3 are cleared to ‘00B’. If interrupts are masked, a reset is the only way to release idle mode.

2.Activate any enabled interrupt, causing idle mode to be released. When you use an interrupt to release idle mode, the CLKCON.4 and CLKCON.3 register values remain unchanged, and the currently selected clock value is used. The interrupt is then serviced. When the return-from-interrupt (IRET) occurs, the instruction immediately following the one that initiated idle mode is executed.

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Samsung S3C84E5 user manual How to Enter into Stop Mode, Idle Mode