6 ms·
> USB link is offhand 3.3V <-> GND
by 15155 2y ago
> USB link is offhand
3.3V <-> GND
- mjevans 2y agoThe data? I checked and Ground and Power pins are 0 and 5V respectively as I recalled. This StackExchange thread has some good diagrams and useful answers: https://electronics.stackexchange.com/questions/190592/why-does-usb-have-vcc-5v-and-high-3-3v https://electronics.stackexchange.com/questions/190592/why-d... Lower speed links are suppsoed to pull the - data pin slightly negative and, effectively, a safely 'TTL high' (relative to 5V source) of greater than 2.8V. The power difference is 5V to better guard against too much loss over a long cable. Higher speed links are quoted as using even lower voltages (the graph appears 0 and 0.4 v swapped as flipped).