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How many operating modes does SPI protocol have?
SPI has four modes (0,1,2,3) that correspond to the four possible clocking configurations. Bits that are sampled on the rising edge of the clock cycle are shifted out on the falling edge of the clock cycle, and vice versa.
Which signal is used for slave mode in SPI?
chip select signal
The chip select signal from the master is used to select the slave. This is normally an active low signal and is pulled high to disconnect the slave from the SPI bus.
What happens when mode fault is enabled in SPI?
The mode fault bit, MODF, is a read-only flag that is set when a mode fault error occurs during transmission and the mode fault enable bit, MODFEN, bit is set to 1. In a master SPI, the MODF bit is set whenever the SS pin goes low. In a slave SPI, the MODF bit is set when the SS pin goes high during transmission.
What are the limitations of the SPI interface?
Following are the disadvantages of SPI: ➨It uses one CS line per slave and hence hardware complexity increases if slave devices are more in the design. ➨In order to add slave device, software needs to be changed and extra CS line is required to be added. ➨No flow control and no acknowledgment used in SPI.
Can a SPI interface have more than one slave?
SPI devices support much higher clock frequencies compared to I 2 C interfaces. Users should consult the product data sheet for the clock frequency specification of the SPI interface. SPI interfaces can have only one master and can have one or multiple slaves. Figure 1 shows the SPI connection between the master and the slave.
Which is the correct MSP430 SPI master setting?
The CC1101 needs to sample with a rising edge clock at the center of the bit time. Clock Phase = 1 and Phase = 0 are the correct MSP430 master settings in this case. Although SPI is full-duplex, oftentimes the data sent by the slave is ignored when the master is writing and vice-versa.
How does a multislave SPI daisy chain work?
Multislave SPI daisy-chain configuration. In daisy-chain mode, the slaves are configured such that the chip select signal for all slaves is tied together and data propagates from one slave to the next. In this configuration, all slaves receive the same SPI clock at the same time.
Who is the controlling device in a SPI relationship?
Devices communicating via SPI are in a master-slave relationship. The master is the controlling device (usually a microcontroller), while the slave (usually a sensor, display, or memory chip) takes instruction from the master.