Maara

USB connectors

9 posts in this topic

Hi Jack,

Just wondered - what will be the ish port type? On the photos, I noticed mini and micro as well... There will be two types of the connectors?

Thanks!

Marek

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Hello Marek,

 

The FT2232H chip connected to the FPGA has a USB Mini connector and the ATmega32u4 has a USB micro connector just like the Arduino Leonardo. It is possible to never use the Arduino Leonardo micro connector, we can route the ATmega32u4 USB through the FPGA. The micro connector is there for some of the advanced features the ATmega32u4 is capable of, such as MIDI controller etc... It is also a third channel for USB communications.

 

Jack.

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What are the electrical rules for the two connectors going to be ? Do they both need to go to the same 5v and ground - eg could one be a power supply and the other a PC, or the two to different PCs ?

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Hello Marek,

 

The FT2232H chip connected to the FPGA has a USB Mini connector and the ATmega32u4 has a USB micro connector just like the Arduino Leonardo. It is possible to never use the Arduino Leonardo micro connector, we can route the ATmega32u4 USB through the FPGA. The micro connector is there for some of the advanced features the ATmega32u4 is capable of, such as MIDI controller etc... It is also a third channel for USB communications.

 

Jack.

Thanks for explanation, Jack!

Could you please consider making both micro usb? The mini usb is getting outdated (nearly all the devices I have are already micro usb including the new arduinos, logic analysers etc.) and there is nearly no benefit in durability of the mini usb connector. Also the footprint is nearly the same. It will also avoid situation like forgetting the cable at home - we can simply use a usb cable for our cellphones.....

 

m.

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One mini one micro at least avoids getting them the wrong way around

 

If you are smart enough to program a fpga, then you are probably smart enough to choose the correct usb port ;-)

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What are the electrical rules for the two connectors going to be ? Do they both need to go to the same 5v and ground - eg could one be a power supply and the other a PC, or the two to different PCs ?

 

There is a physical jumper that only allows the 5V power pin of one USB port to be connected at a time. I felt this was the safest and cleanest way to prevent different 5V sources from causing problems. Only one USB jack at a time can power the board.

 

Jack.

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Thanks for explanation, Jack!

Could you please consider making both micro usb? The mini usb is getting outdated (nearly all the devices I have are already micro usb including the new arduinos, logic analysers etc.) and there is nearly no benefit in durability of the mini usb connector. Also the footprint is nearly the same. It will also avoid situation like forgetting the cable at home - we can simply use a usb cable for our cellphones.....

 

m.

 

I struggled with this decision for several days... I decided to go with the different jacks in order to make it easier to keep them separated. The Leonardo has always used micro and Papilio has always used mini. I don't think there was really any right decision here, someone is always going to wish you decided the other way... Also, I figure that most people have a ton of both cables on hand...

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I like the mini USB.  Yes, I know that the standard says that the micro is more reliable, but it's pretty well impossible to tell if cables you buy strictly meet any standard.  So I figure larger connectors = more robust = longer lasting.  Micro USB does not give me confidence.

 

All of my dev board have mini USB except Raspberry Pi.  So I have lots of mini USB cables.

 

I also like having the different connectors to so you can tell them apart.  Maara said: "If you are smart enough to program a fpga, then you are probably smart enough to choose the correct usb port ;-)"  Well, that may be true once you're up to speed, but don't we want to be as accessible to newbies as possible?

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