Samsung S3C2440A User Manual

Page 226

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S3C2440A RISC MICROPROCESSOR

CLOCK & POWER MANAGEMENT

7

-19

Output Port State and SLEEP Mode

The output port should have a proper logic level in power off mode, which makes the current consumption
minimized. If there is no load on an output port pin, H level is preferred. If output is L, the current will be consumed
through the internal parasitic resistance; if the output is H, the current will not be consumed. For an output port, the
current consumption can be reduced if the output state is H.

It is recommended that the output ports be in H state to reduce current consumption in SLEEP mode.

Battery Fault Signal (nBATT_FLT)

There are two functions in nBATT_FLT pin, they are as follows;

— When CPU is not in SLEEP mode, nBATT_FLT pin will cause the interrupt request by setting

BATT_FUNC(MISCCR[22:20]) as 10x’b. The interrupt attribute of the nBATT_FLT is L-level triggered.

— While CPU is in SLEEP mode, assertion of the nBATT_FLT will prohibit the wake up from the sleep mode,

which is achieved by setting BATT_FUNC(MISCCR[22:20]) as 11x’b. So, Any wake-up source will be masked
if nBATT_FLT is asserted, which is protecting the system malfunction of the low battery capacity

ADC Power Down

The ADC has an additional power-down bit in ADCCON. If the S3C2440A enters the SLEEP mode, the ADC
should enter its own power-down mode.

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