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ADVANCED COMMUNICATIONS & SENSING

DATASHEET

SX8124

24 hours timer synchronized on 50/60Hz mains

ACS - Revision 2.4

October 2010

© Semtech Corp.

6

24h Timer

6.1

Operating

The pin START is used to change the OUT (and NOUT) state. A short pulse (below 1 second) on this pin

manually changes the OUT and NOUT state (Figure 6). A long pulse (around 3 seconds or more) resets the

system and restarts the synchronization of the chip on its PHASE input.

6.2

Debounce on START pin

The START pin is active low. For a start/stop command detection, the voltage on the START pin must be

maintained low during 10ms. Then, a delay of 20ms is necessary before the next start/stop command.

This allow to remove wrong start/stop commands due to oscillations when using of low-cost push buttons.

Figure 5. Outputs waveforms during the 24 h cycle

Figure 6. Outputs toggling pushing START pin down during less than 1 second

OUT

24h cycle

Next 24h cycle

NOUT

start timer

toggle at set duration

(re)start

24h cycle

Next 24h cycle

START

OUT

NOUT

pin toggle

start timer

(re)start

pin toggle

Short low pulse

Short low pulse