sx8724s Semtech Corporation, sx8724s Datasheet - Page 42

• Manufacturer Part Number: sx8724s
• Description: Zoomingadc For Sensing Data Acquisition
• Manufacturer: Semtech Corporation

Revision 1.0
© Semtech
9.4 Chip Start Detection with Slave Select Pin
At power-up or after a soft reset, SS pin is set to output low during the chip initialization (~250us). If the host SS pin is
configured at an input pulled high during the power-up sequence, it can detect the SX8724S effective start.
Note that if the host pin has a default output high logical level during the power-up or reset sequences this output it
will create a short circuit. Therefore, a resistor should be put on the line to ensure that no current spikes are generated.
The best value for SS resistor should be between 1 kΩ and 10 kΩ. In that range, the current spike is completely avoided
and the falling/rising time is ensured.
On
output for SPI Slave Select. As in the precedent figure, the resistor on the line to ensure that no current spikes are
generated when Master and Slave SS pins are both configured as outputs during a startup sequence.
ADVANCED COMMUNICATIONS & SENSING
Figure 30
the SPI master uses a separate input for startup status reading. The master SS pin is always configured as
Figure 29. Set a resistor if the host is a high logical level during the startup or the reset
February 2011
MASTER
MASTER
Figure 30. SPI Master using a separate input for startup status reading
MISO/READY
Sx_rdy
SCLK
MOSI
SS
SS
10K
Page 42
10K
ZoomingADC for sensing data acquisition
SCLK
MOSI
MISO/READY
SS
SS
SX872xS
SX872xS
SLAVE
SLAVE
SX8724S
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