Systems and methods for concatenating multiple devices

A method comprising:

• determining if a slave select (SSEL) line included in a SPI bus is active;
• determining if a chain line is active;
• if the SSEL line and the chain line are both active then:
• receiving a command having M bits by using a master output slave input (MOSI) line included in the SPI bus;
• transmitting a response by using a tristate-enabled master input slave output (MISO) line included in the SPI bus;
• determining if the SSEL line is still active;
• and
• if the SSEL line is still active, then asserting a chain output port active.

A non-transitory tangible computer-readable medium comprising executable code, the executable code comprising instructions for:

• determining if a slave select (SSEL) line included in a SPI bus is active;
• determining if a first chain line is active;
• if the SSEL line and the first chain line are both active then:
• receiving a command having M bits by using a master output slave input (MOSI) line included in the SPI bus;
• transmitting a response by using a tristate-enabled master input slave output (MISO) line included in the SPI bus;
• determining if the SSEL line is still active;
• and
• if the SSEL line is still active, then asserting a second chain line active.

A system comprising:

• a serial peripheral interface (SPI) bus;
• a master device communicatively coupled to the serial peripheral interface (SPI) bus;
• a first slave device communicatively coupled to the SPI bus;
• a second slave device communicatively coupled to the SPI bus and to the first slave device;
• and
• a third slave device communicatively coupled to the SPI bus and to the second slave device;
• wherein the first, the second, and the third slave devices are communicatively coupled in parallel to the SPI bus, the first and the second slave devices are communicatively coupled to each other by using a first chain line, the second and the third slave devices are communicatively coupled to each other by using a second chain line, and the master device is configured to communicate with the first, the second, and the third slave devices over the SPI bus, and wherein the third slave device and the second chain line are provided as part of a kit, and wherein the kit comprises instructions to add the third device by connecting the third device to the SPI bus in parallel and by connecting the second chain line to a chain out port included in the second device and to a chain in port included in the third device, and wherein the master device is not reprogrammed.