Interfacing of Micro-controller with USB using SPI with Isolation
USB - Universal Serial Bus, It is very common usable Communication protocol of new technologies in the field of Electronics and Communication.
We easily get lot of support of USB interfacing with micro-controller but that all are using USART protocol available on micro-controller or some controller may have internal hardware of USB.
Some time problem comes when we are using more than one communication protocol in single board
with single micro-controller because we have limited communication protocol available on micro-controller.
To solve this issue we can use any free protocol to interface USB but for that we need to use external hardware for that.
Here we will discuss the SPI port interfacing woth USB.
We easily get lot of support of USB interfacing with micro-controller but that all are using USART protocol available on micro-controller or some controller may have internal hardware of USB.
Some time problem comes when we are using more than one communication protocol in single board
with single micro-controller because we have limited communication protocol available on micro-controller.
To solve this issue we can use any free protocol to interface USB but for that we need to use external hardware for that.
Here we will discuss the SPI port interfacing woth USB.
Figure(1)
Isolated USB Interfacing with SPI Protocol
SPI have 4 Pins
1. SCLK - Serial Clock Generated By micro-controller
2. SS - Slave Select
3. MOSI - Master Out Slave In
4. MISO - Master In Slave Out
we use few other for batter implementation of Protocol.
1. INT - USB will Interrupt the micro-controller when external host device want to communicate.
2. RESET - USB will also get reset when Micro-Controller will get Reset by hardware .
In above pin description Master is Microcontroller and Slave is USB, In SPI protocol Master send clock on SCLK Pin and Select the USB(Slave device) for communication. Data from micro-controller (Master) to USB (Slave) will go through MOSI (Master Out Slave In) and reverse will happen using wire MISO.
W need Hardware and Software to use this protocol, here we discussed the hardware portion the software is under test and will be updated here soon.
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