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@ -3,7 +3,7 @@ the CuVoodoo USB hub is a 7-port USB 2.0 hub meant for device testing. |
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purpose |
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======= |
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most USB hub are super cheap and crappy, leading the poor connection connection and data transfer. |
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most USB hub are super cheap and crappy, leading to poor connection and data transfer. |
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there are industrial USB hubs, but they are bulky and very expensive. |
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to solve this issue I decided to design my own USB hub, tailored to my needs. |
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@ -18,7 +18,7 @@ this device is a 7-port flat USB hub, preventing reaching this limit too often. |
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the incoming and outgoing USB ports are individually ESD protected. |
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this safety becomes important when developing, testing, and handling bare electronic devices. |
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this also comes in handy against when connecting circuit with different ground potentials. |
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ESD protections already saved my day twice. |
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ESD protections already saved my day twice this way. |
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the issue is that they can blow without you noticing, but at least they protected the device once. |
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each output port is current limited to 500 mA. |
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@ -34,17 +34,17 @@ this is an important requirement when developing and testing devices, which requ |
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additionally, a switch next to the power can force the power off state. |
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the USB hub can be self-powered (through the USB input port), externally powered by 5V, or externally powered by anything between 6 and 40V. |
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this allows to use higher voltage power supplies to provide enough current to all power. |
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this allows to use higher voltage power supplies to provide enough current to all ports. |
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the 5V are not feed back to the host. |
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each output port comes with a high voltage output power port, connected to the high voltage input port. |
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each USB port comes with a high voltage output power port, connected to the high voltage input port. |
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this allows to power devices which require more than 5V (e.g. 12V externally powered devices). |
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each of these power output is controllable. |
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these power outputs are controllable. |
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as with the 5V USB power output, this allows to remotely switch on an off individual devices. |
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each port has status LEDs, indicating the speed and power of the connected device. |
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each port has status LEDs, indicating the speed and power status of the connected device. |
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the board uses proper impedance and differential signal routing to provide clean USB transfer. |
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the board uses proper impedance and differential signal routing to provide clean USB signal transfer. |
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design choice |
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============= |
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@ -67,16 +67,24 @@ and it is easier to solder thanks to its TQFP package, and provides all required |
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sadly I could not find a source for the 64-pin packages, and the 48-pin variant does not provide all required functionalities. |
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thus I had to fall back to the Microchip USB2517, which uses a harder to solder QFN package. |
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power control |
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some USB hub chips allow to remotely control the power output on individual ports. |
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this capability is here also used to control the power on the higher voltage output. |
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thus you can completely power off even larger target devices. |
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current limitation |
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------------------ |
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the few USB hubs that have current limitation on the output, use a MIC2026. |
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very few USB hubs that have current limitation on the output. |
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this does limit the current to 500 mA, but only in constant current mode. |
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the fault is reported (e.g. to the hub, back to the computer), but it is up to the user to power off the faulty device. |
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instead I use poly-fuses, which automatically cut the power once the limit of 500 mA is reached. |
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this is faster, and removes user-based actions. |
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the fault is still reported. |
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if well designed, the fault is also reported to the computer. |
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sometimes the hub also turns off the power, or it is up to the user to power off the faulty port. |
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on this hub, the fault is reported, and the power is automatically disabled, preventing damages on the device due to prolonged shorts. |
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this is very useful when testing devices. |
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the power is restored once the current limit is cleared. |
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LED color |
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--------- |
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