Serial port cable
#11
(03-11-2020, 03:37 PM)z4v4l Wrote:
Quote:(IIRC 3.3v is, strictly speaking, slightly over-volted too... but hopefully it is within engineering tolerances
not accordingly to the rk3399 datasheet, which claims 3.15 V as the acceptable maximum to that power domain.

I though that was the maximum for the power rail and the power rail is actually running at 3.0v (e.g. a 3.3v adapter will over-volt the RX pin by 0.3v, not 0.15v).

(when I bought my PBP I did also ordered some diodes with a forward drop of 0.3v and intended to use these to make hooking up an external programmer to the SPI FLASH strictly correct... however I'm not sure I can currently find them).

Edit:
Sorry, just realized I rather overlooked the obvious bit (I haven't looked the schematic for a while) which is that the engineering tolerance in the design doesn't come from the power rail anyway: it comes the 100 ohm resistors in series with TX and RX.
PineTime: wasp-os and MicroPython, Pinebook Pro:  Debian Bullseye
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Messages In This Thread
Serial port cable - by bsammon - 03-06-2020, 04:11 PM
RE: Serial port cable - by tllim - 03-09-2020, 06:00 PM
RE: Serial port cable - by z4v4l - 03-09-2020, 07:06 PM
RE: Serial port cable - by danielt - 03-10-2020, 02:16 AM
RE: Serial port cable - by zaius - 03-10-2020, 11:56 AM
RE: Serial port cable - by danielt - 03-11-2020, 08:53 AM
RE: Serial port cable - by zaius - 03-11-2020, 01:00 PM
RE: Serial port cable - by danielt - 03-11-2020, 02:41 PM
RE: Serial port cable - by zaius - 03-13-2020, 12:37 PM
RE: Serial port cable - by danielt - 03-16-2020, 08:18 AM
RE: Serial port cable - by zaius - 03-16-2020, 12:44 PM
RE: Serial port cable - by vrabac - 03-10-2020, 12:25 AM
RE: Serial port cable - by z4v4l - 03-11-2020, 03:37 PM
RE: Serial port cable - by danielt - 03-12-2020, 04:48 AM
RE: Serial port cable - by xyzzy - 11-18-2020, 09:59 PM
RE: Serial port cable - by mattpenn - 03-03-2021, 08:32 AM
RE: Serial port cable - by tllim - 03-04-2021, 12:49 AM
RE: Serial port cable - by mattpenn - 03-04-2021, 10:00 AM

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