New answers tagged

0

You can parallel two Solar panels of the same voltage, although the battery pack accepts more power on the USB-C port at 18W=9Vx2A than the 10W=5Vx2A port. So I would be looking for a 9V Solar panel in the 25W range which would have an open circuit voltage of 12V (Voc). Then you need a UBC-C cable and wiring diagram. However I don't find anything in a ...


0

So it appears the answer was two-fold: Replace the REF resistor with 12k Use a good USB cable Thank you for all your contributions!


1

A host must provide 5V power supply to device. A host will wait for a device to appear before doing any communications to device. Host always initiates any communication. A device can use 5V for powering itself, or if it is self-powered, simply sense when host connection is made or disconnected. A device will always wait for communication from host. OTG ...


0

So I learned and answered my original Questions after some R&D : ESD protection is different for Digital I/O Lines Power Lines Digital IO Lines : as they are usually one way Industry preference if for high preference for unidirectional TVS Additionally CMOS inputs are VERY sensitive to negative spikes, and unidirectional TVS have IV characteristic ...


0

I doubt the CC pins are exposed to applications since they're an internal part of the USB connection and not something an application should have access to. Instead, a better option would be to use the USB data pins: https://code.google.com/archive/p/android-serialport-api/wikis/android_to_rs232_guideline.wiki This is officially supported and much more ...


2

You want a Type C so connect the CC pins as per Type C as they don't exist in USB 2. The rest must be done according to USB 2. If you want to read more about it then the read the USB specs, they have everything you need. You have also shorted D- directly to 5V, that will damage your PC and your device, don't do that. Besides the pull-up resistor would not be ...


0

It does need drivers - but you are using a standard protocol (USB CDC), so Linux already has the drivers built-in. The USB/UART chip knows how to speak the USB CDC protocol, and so does Linux. If you have your own chip that speaks USB (but not CDC) then you will need to give Linux a driver so it knows how to speak the chip's protocol. You could also use a ...


2

Low-speed USB devices are allowed to have their cable to be unshielded. Some makers use these cheaper cables to reduce device's cost and have more flexible (user-friendly) cables. These cables are prone to external radio interference, including small ESD events that always happen, especially in dry-air winter time. With unshielded cable all interference goes ...


0

Every laptop that charges from USB-C must have a dual role capable controller, that means it can act as host or device. USB-PD requires this. This is proven by plugging in a laptop to another "host" computer as if the other computer is a charger. The host computer will list the laptop as a USB device, again it must if the laptop is going to get ...


0

Both Qualcomm QC and Apple FAst charge are proprietary protocols not disclosed to general public. Both would require a special hardware (at least high-side VBUS controller) to implement, so this is definitely outside the scope of any software driver. So you will need to identify what kind of special/particular IC(s) is(are) used for this function. Typically ...


2

USB does not allow two hosts to be physically connected together. So it is not possible, unless you can figure out a mechanism to make your PC USB port to switch from host mode to device mode. And that may not be possible, if the configuration is done in hardware.


4

It could, depending on how it is built, and how you will short it. If simply shorting 5V to GND, it could survive many events. Shorting 5V to data pins can damage the data pins. Shorting 5V to some other higher voltage in the circuit can damage the whole laptop. If you like to have working USB ports and laptops, don't use your laptop as a power supply.


0

check datasheet page 10, you might need to connect Pin 59. This pin is PowerSav# Input. there is example later in the datasheet for self powered device. p.s. Why do you have USB ID pin grounded? you need USB OTG? if i remember correctly, when ID pin grounded means in OTG, becoming a USB HOST. Where your FTDI can not be USB HOST.


1

USB High Speed device support necessarily comes with USB (full speed, at least) Host support Absolutely NO. "Device support" and "Host support" are two entirely different functions and require different hardware blocks. HS (high-speed 480 Mbps) USB Host support requires probably 10 times more resources than a "HS device". That'...


3

It's quite possible that the core voltage cannot handle 3.3V and the chip was fried, so replace the chip (although this is just a hunch, the datasheet is mum on the subject (which is a big problem for not having absolute max ratings listed)) Vcore needs a power filter cap. +1.8V Output. Integrated voltage regulator output. Connect to VCORE with 3.3uF filter ...


0

The best way that fits in with ST's software stack is to implement these functions: void HAL_PCD_ConnectCallback(PCD_HandleTypeDef *hpcd); void HAL_PCD_DisconnectCallback(PCD_HandleTypeDef *hpcd); These are declared with weak linkage in the HAL stack so your implementations will override the HAL do-nothing stubs. However, if you're using Cube then you'll ...


2

Yes. You can splice in-between the battery pack and the female usb plug or the usb male plug and that black rectangle. Either the V+ or the Ground (unless both the shield and ground are tied together). Color is not guaranteed so make sure you use a multimeter to figure out which is which. Personally I would add the switch to the case if you can. No added ...


0

Awsome, I inserted a 2 second delay: ser = serial.Serial('/dev/ttyUSB0', 9600, timeout=1) time.sleep(2) ser.write(b"Hello 1 from Raspberry Pi!\n") and now I am seeing the expected output !! You sent me: Hello 1 from Raspberry Pi! You sent me: Hello 2 from Raspberry Pi! You sent me: Hello 3 from Raspberry Pi! Thanks!!!!


2

Probably you are losing the first line to the bootloader delay of the Arduino, after opening the port triggers a reset via the traditional wiring of the modem control lines to the ATmega reset, and the traditional default manipulation of those on serial device open. Generally speaking you want to avoid using time delays to make serial code work, but in this ...


0

The problem of expandability of "light" moible devices with only one Type-C port has a standard solution called "docking station". Docking stations usually have a USB hub to expand USB functionality, usually already have a USB-to-LAN device, and can switch roles of USB-C ports, both power role and data role, and also can engage the ...


3

The test for backfeed is fairly simple. You need to make a dummy USB port with VBUS, D+ and D- loaded with 15 k resistors. When you plug your hub-switch combination into this "fake"/test port, voltages on any of the pins (VBUS, D+, D- ) should not exceed 400 mV. See the Back Voltage test description here. For schematics of the test fixture, see ...


0

"The Universal MIDI Packet format adds a (optional) Jitter Reduction Timestamp mechanism. A Timestamp can be prepended to any MIDI 1.0 Protocol message or MIDI 2.0 Protocol message for improved timing accuracy. " from https://www.midi.org/midi-articles/details-about-midi-2-0-midi-ci-profiles-and-property-exchange "You must be logged in as a ...


1

I'm 99.99% certain that those 5V outputs are parallel connected on the board so they can't be series connected off the to produce 15V if you need 15V consider using a boost converter module. prices start below $1 eg: https://www.aliexpress.com/item/4000375259194.html


1

No, they are almost certainly not isolated. You can't stack them in series unless they are isolated.


1

There are two approaches I would suggest. Simplest approach Permanently connect a power resistor in parallel with D1 to provide a minimum load on the alternator. e.g. 220 or 470 ohm. This will prevent the output voltage from rising too high but has the disadvantage that it will 'steal' some power from the load. Nevertheless, you may be able to find a ...


0

Bicycle "dynamos" (alternators really) can be modeled as an AC voltage generator with an output voltage and frequency proportional to speed, with a large winding inductance in series. As speed increases, frequency increases, which means the reactance of the inductance (Lw) increases, which limits the current, and... you get an AC current source. ...


0

An OVP circuit I have used in the past with success in bike dynamo applications is to use a TRIAC which is triggered by a RC combo with a DIRAC, as shown below. You can adjust the trigger point by customizing the DIRAC, R and the C components to your liking. The idea is that the TRIAC will get tripped and short out the dynamo for the part of the signal ...


1

There is a fundamental problem with the word 'charger', which is designed to charge a battery. It is different from a 'power supply', which is designed to power a device. The two things can and generally do behave differently. They are designed to behave differently. However, people often use the two terms interchangeably, so confusing them. Sometimes a ...


1

Your switch has only two poles, for D+ and D- I assume. For a PC to recognise new connection (after disconnect/loss of communication), the VBUS also heeds to be switched and needs to go through zero voltage state. And, of course, ground needs to be connected all the time. The VBUS toggle will ensure that there will be another connect event, and also that the ...


4

As it turns out, my multimeter battery was under-voltage, and this was the source of seeing the high reading on the USB power. With a fresh battery I now see 5.01 V across the 5V terminals. On a new ATX power supply I have -12.01 V, -5.01 V, 5.01 V and 12.30 V on the nominal -12, -5, 5 and 12 volt terminals. The low battery also affected readings across ...


1

Unfortunately, yes, you missed something important. USB uses fast digital signals. How fast depends on which version of USB (Low Speed, Full Speed, High Speed, Super speed) but they vary from very quite fast to ludicrously fast. Fast signals need special care when laying out PCBs, or making cables. This is a complicated subject, so I'm not going to try to ...


4

If it's a cheap power circuit, it might need a tiny minimum load to get within the specified voltage. Would expect to see this on dollar-store USB-chargers, not from a computer! Put a 5k resistor on it and see what it does.


8

The USB specification says 4.4 V or 4.45 V to 5.25 V for VBus. Some non-standard USB supplies will be higher to combat the voltage drop over a long wire and high current, but it is not within normal specifications. Are you measuring under load? That would be important. Most devices will regulate down and even 5 V ICs tend to tolerate up to 6 V, so it's not a ...


3

No, it is not in tolerance according to specifications. It is too high. Edit: Based on comments by OP, the summary is that most likely the issue was not that actual voltage was too high on the USB port, but simply that the multimeter was low on batteries and it gave too high readings because of this.


Top 50 recent answers are included