What is Daisy Chaining?
This page describes basics of Daisy Chaining. It mentions advantages of Daisy Chaining. It also mentions Daisy Chaining Switches.
The process in which devices are interconnected in series one after the other is known as daisy chaining. It is equivalent to series circuit.
As we are aware that many of the SPI devices can not be addressable individually. They need separate extra hardware in order to be interfaced with single device on bus. This hardware complexity is avoided in daisy chain architecture. This is shown in the figure-1.
Here commands issued from microcontroller propagates from one slave device to the other. Here DOUT of first device is connected with DIN of the next device and so on.
Daisy Chaining execution cycle
Figure-2 depicts daisy chaining execution cycle diagram. Hence during active low of CS, commands are loaded into register of 3 devices one by one during 3 clock SCLKs. Each SCLK consists of 16 cycles. Once the commands are loaded they can be executed by making CS signal to HIGH state.
Following are the advantages of Daisy Chaining:
• Hardware complexity is less in the design of multiple slave devices to be controlled by one master device.
• The operation of selection of slave devices and execution of commands is easy with the use of software programming.
• It is scalable. Hence nodes or devices can be easily added to the chain upto the maximum limit of the interface bus standard used. For example SCSI-2 supports maximum of 16 devices/nodes.
The latest Thunderbolt technology based devices support daisy chaining.
Refer Thunderbolt1,2,3 for more information.
Switches which can be connected in daisy chain fashion is known as daisy chain switches. Hence check for the option while purchasing ethernet switches for use whether they support daisy chaining or not.