Quote:
Originally Posted by x23are
i back after three or four hard weeks.
i bought a usb2ttl board. it have a 5v and 3v3 on it.
i know i must connect kindle tx to board rx and kindle rx to board tx.
and connect gnd to gnd.
and now where is the vcc? on the kindle or an external source?
dear knc1 notice me about the 1v8 and level shifter.
but i know it is a strange question but i confused.
where is the vcc source for usb2ttl board?  |
If you meant vcc to the board:
Almost always, it is provided from the USB power on the USB cable.
In general, it depends on the device.
If you meant the **I/O reference voltage (1v8)** to the board:
You can take the external 1.8 volt reference from a Li/Fe chemistry battery.
See:
https://www.mobileread.com/forums/sho...85&postcount=8