# Tag Info

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Turns out I had soldered by mistake an Attiny841 instead of the MCP2221... Same package, and the Atmel's marking is incredibly difficult to read!

1

LEDs are current controlled devices. You will surely either fry them sooner or later unless you control the current OR the LEDs won't lit due to insufficient voltage. Have a series resistor based on the required current Or choose a LED driver IC or a constant current circuit for efficiency if you are powering multiple LEDs.

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We have had the same issue with similar USB connectors. At the present Eagle doesn't have an option for creating slotted pads, however there is a workaround described in this Eagle forum. In a nutshell, create a component in your library that has (as described by Rachael): A PAD on each end of the slot and then draw each of the inner/outer layer pad ...

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It's not exactly clear, what you are saying. What I got is: 1. you have a USB device, that provides only wire leads 2. you want to connect to external USB port of the computer You can cut an existing USB cable and solder or wrap wires together. Normally there would be some sort of filtering on any USB peripheral, so I guess you can try without anything ...

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I send information directly from technical support zebex. Note the additional barcode scanner pinout connection: Scanner (RJ50) - USB 1-2 (USB Power, + 5V) - 1 6-7 (TxD - RxD)

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This is the table in the buyers guide: It specifies 10P10C connector. For an 8P8C connector the mapping would be RJ45 pin 1 - +5V RJ45 pin 2 - D- RJ45 pin 4 - GND RJ45 pin 7 - D+ An RJ45 connector can be inserted into such an RJ50 socket, the pin counting is then reduced by one. This connector is also used by some vendors, [...] allowing an 8P8C plug ...

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You cannot ever get to the "rated speed" on any peripheral link because the rates are usually expressed in raw bits per second, and every link has packet framing, encoding overheads, and protocol overheads on every level on connection stack. So the "1.5 MB/s" is not possible to achieve even in theory. The internet-quoted transfer rates (800 kB/s WRITE and ...

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The possible outcomes from overloading a USB port range from temporary shutdown to permanent damage. I've seen cases where the USB 5V supply thrashes between 0 and 12-15V, causing damage to both the host and the peripheral. There's very little consistency. USB negotiates current available, and USB-C has an analog alternative mostly for charger purposes. ...

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From the datasheet: Breakdown voltage, IO to GND is the critical parameter. Some parts may conduct at 4.5V, shorting the 5V VBUS to ground and other may not. This is not a suitable part for VBUS ESD protection.

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I have just put 5 volts right on the + and - of were the battery would go. They do have another pin I guess for sense. I did it on 2 old cellphones that the battery went bad on. But they only stay going for about a day. It thinks the battery is draining down very low so it turns off. I guess have to put something on the 3rd pin but I don't know what. I ...

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You will be connecting all devices in parallel, so the voltage requirement stays constant at 5V. To get the needed current just sum up all device input currents. If you have 4 devices with 2A each you need 8A. The power is V*I, in this case 40W. If you want to power the devices from battery for a longer time, you obviously also have to keep in mind the ...

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I don't know who designed that board, but it has several questionable connections. First, CH340C chip datasheet requires V3 pin connected to VCC if VCC is 3.3V. On the board it is permanently connected to decoupling capacitor, which corresponds to 5V configuration. On the other hand, the LEDs are connected to 3.3V supply, so they will (maybe) operate in ...

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Soldering them is difficult because the surface mounts are very tiny, it requires steadily holding the wires in place, and since the area is so small, the solder crosses over to the other surface mount areas. SMD soldering requires a non-trivial amount of training (and flux). You don't want to train on stuff that needs to be in working condition. And even ...

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If you really need High Speed, your best bet is likely to be two EZ-USB FX2, each handling one port, and one of the chips being able to send the other into suspend mode (or a proper protocol with gracious shutdown instead of generating a surprise eject event).

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You will need a mux to switch between the two data lanes. You could, for example, use an FSUSB42 with the respective $V_\mathrm{BUS}$ for the Sel line. Power switching may be a little trickier, but hard to say without knowing what you have downstream from the USB ports. Bear in mind, this will cause problems when the user plugs in the "master" USB while ...

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Short answer, no you can't use random headphone wiring you don't know anything about for USB 2.0 signaling. It requires a twisted pair with specific impedance for differential signaling and thick enough wires for supplying the rated amount of current without too much losses. Get a USB extension cable.

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There is no "filtering" on your usb port. On my STM32F's I usually use 22 ohm resistors like they do on the dev boards. It cleans up the eye diagram of the USB. As far as the rest of the design, it's probably not very noise proof. If you are having problems with random dropouts then the design is probably susceptible to external noise corrupting packs from ...

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Several potential issues exist that I can see. Firstly, your "decoupling caps" should be as close to the pins they are inteded to decouple (usually the IC power pins). This can cause all sorts of weird behaviour in digital circuits. Your D+/D- diff pair is not routed with constant spacing, which could cause signal integrity problems due to impedance ...

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Using a relay as Michael Jennings suggests is a good solution. If you want the easiest possible solution then a premade relay module which are available on Amazon [ Many examples here ] and various Asian sites would be a good choice. A more DIY electronic solution is to use a transistor as a switch. I've shown a MOSFET here but an NPN transistor could ...

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You could use a 5V relay module like this one. Your design will have the following connections: DC+ to USB 5V DC- to USB 0V IN1 to USB 5V NO to your raspberry pi 5V in COM to the 5V raspberry pi wall wort/plug socket power supply NC disconnected N.b The wall wort power supply's ground also needs connected to the raspberry pi. This can be connected directly ...

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Your understanding is correct. USB packets go both ways, so SYNC, PID, DATA, CRC, and EOP are formed by whoever sends the particular packet. And yes, a device (at HS rate of signaling) must respond in 192 bit times (400 ns) to standard requests. [the host, however, will wait 1700ns before declaring time-out, to accommodate for other propagation delays along ...

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