Texas Instruments TRF7960 Manual page 37

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6.8.1 SPI Without SS* (Slave Select) Pin
The serial interface without the slave select pin must use delimiters for the start and stop conditions.
Between these delimiters, the address, data, and command words can be transferred. All words must be
8 bits long with MSB transmitted first.
SCLK
Data IN
Data OUT
In this mode, a rising edge on Data IN (I/O_7, pin 24) while SCLK is high resets the serial interface and
prepares it to receive data. Data IN can change only when SCLK is low and is taken by the reader on the
rising edge of SCLK. Communication is terminated by the stop condition when the falling edge of Data IN
occurs during a high SCLK period.
6.8.2 SPI With SS* (Slave Select) Pin
The serial interface is in reset while the SS* signal is high. Serial data-in (MOSI) changes on the falling
edge, and is validated in the reader on the rising edge, as shown in
terminated when the SS* signal goes high.
All words must be 8 bits long with the MSB transmitted first.
SCLK
MOSI
SS*
Figure 6-11 shows the SPI read operation.
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Start
Condition
50 ns
b7 b6 b5
Figure 6-9. Serial – SPI Communication (No SS* Pin)
B7 B6 B5
Figure 6-10. Serial – SPI Communication (Write Mode)
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SLOU186G – AUGUST 2006 – REVISED MAY 2017
b4 b3 b2 b1
B4 B3 B2
TRF7960 TRF7961
TRF7960, TRF7961
Stop
Condition
b0
Figure 6-10. Communication is
B1 B0
Detailed Description 37