SPI has the ability to support high data rates and full duplex data communication while having a simple hardware interface and complete protocol flexibility for the bits transferred. Due to these advantages, SPI is implemented in many application use cases. Video Doorbell is one example of the use of SPI protocol. It is the preferred communication method for sensors, control devices, camera lenses, memory, LCD, and SD cards.

Another notable use case involves the control devices in the two way audio communication block. The SPI communication protocol is commonly used in ADC, DAC, CODEC, and DSP processors. Another critical advantage of using SPI instead of I²C for these devices is that SPI allows for a faster data rate. This results in a higher sample rate, which produces better sound quality.

Figure 3-1 SPI Interface Using SN74AXC4T245 and 2N7001T Devices

Figure 3-2 SPI Interface in Video Doorbell