SQIO Overview

The main purpose of SynqNet I/O (SQIO) is to provide general-purpose I/O. If you are interested in motion related I/O, please refer to the RMB-SynqNet.

SQIO is a modular system, in which a node is comprised of the following:

A SQID, which serves as the SynqNet network interface and power source for all connected I/O boards.
And one or more board modules that can be cascaded to provide as much I/O as is required.

Communication between the board modules and the SQID uses SPI1 type serial busses.
The four SPI busses are used as follows:

SPI Serial Bus	Description
SPI 0	Digital Inputs. Provided in banks of eight. Up to 256 inputs in total. Located on the DIN32DOUT32 module.
SPI 1	Digital Outputs. Provided in banks of eight. Up to 256 outputs in total. Located on the DIN32DOUT32 module.
SPI 2	Analog Inputs. Provided in banks of four channels. Up to sixteen 16-bit inputs in total. Located on the ADC4DAC4 module.
SPI 3	Analog Outputs. Provided in banks of four channels. Up to sixteen 16-bit outputs in total. Located on the ADC4DAC4 module.

Communication Diagram

Each SPI bus either passes through the logic circuitry of a board module or is merely tracked-through.

The board modules are easy to use and are simply slotted together via the SPI bus. They are auto-enumerated and require neither DIP switch settings to set addresses nor loop-back connectors at the end of the each SPI chain.

Board modules appear to SynqNet as a “chain of bits.” This is a simple but useful abstraction: a knowledge of the SPI busses is all that is required to design a custom board module. Neither special controller software nor special SQID FPGA logic is required.

¹ A trademark of Motorola.