Hey guys, I hope this is the correct spot for my question!
I have a microcontroller that is communicating with a number of different sensors using a SPI bus. If you are unfamiliar, this is basically a communication protocol where you send digital signals through 4 wires (clock, data in, data out, and a select). Similar to this image shown below (only difference is that my slave select (SS) is all connected together as well - not important for my question though):
Each sensor has 2x cable ports so that the sensors can be daisy chained together (everything is connected in parallel basically). I found this image which gives you an example/idea on what I mean by daisy chaining the devices:
Now for my questions:
1. It seems that I should use some kind of a signal booster/amplifier. The microcontrollers all communicate with a digital signal (0 to 3.3 volts) and I'm almost certain I can't just put that directly on the line. I am imagining that I run this digital signal into something that will turn it into like a 0 - 12 volt signal before sending it down the cable. Would I just use something like a transistor or an opto-coupler? Then on the other side do the opposite, take that signal back down to 0 to 3.3 volts and then into the sensors microcontroller. Are there any chips out there already for specifically this purpose? Is there anything else I should take into consideration?
2. Is it ok for me to use RJ45 cables, or USB cables? Both cables can handle a decent amount of current in the wires, both are shielded, and both have enough wires in them. What is the best way to handle the twisted pairs? Would I just ignore the fact that there are twisted pairs in the cable, or should I utilize them somehow?
Thanks guys and any help is greatly appreciated!
I have a microcontroller that is communicating with a number of different sensors using a SPI bus. If you are unfamiliar, this is basically a communication protocol where you send digital signals through 4 wires (clock, data in, data out, and a select). Similar to this image shown below (only difference is that my slave select (SS) is all connected together as well - not important for my question though):
Each sensor has 2x cable ports so that the sensors can be daisy chained together (everything is connected in parallel basically). I found this image which gives you an example/idea on what I mean by daisy chaining the devices:
Now for my questions:
1. It seems that I should use some kind of a signal booster/amplifier. The microcontrollers all communicate with a digital signal (0 to 3.3 volts) and I'm almost certain I can't just put that directly on the line. I am imagining that I run this digital signal into something that will turn it into like a 0 - 12 volt signal before sending it down the cable. Would I just use something like a transistor or an opto-coupler? Then on the other side do the opposite, take that signal back down to 0 to 3.3 volts and then into the sensors microcontroller. Are there any chips out there already for specifically this purpose? Is there anything else I should take into consideration?
2. Is it ok for me to use RJ45 cables, or USB cables? Both cables can handle a decent amount of current in the wires, both are shielded, and both have enough wires in them. What is the best way to handle the twisted pairs? Would I just ignore the fact that there are twisted pairs in the cable, or should I utilize them somehow?
Thanks guys and any help is greatly appreciated!