[Ovmsdev] OVMS v3 getting started

Mark Webb-Johnson mark at webb-johnson.net
Tue Sep 26 17:51:14 HKT 2017


Both FTDI and CP2102 roll their own drivers and supply for the major operating systems. I think the reason to use an external device (rather than direct USB on the micro controller) is to make the boot loader code simpler (for flashing, etc) as just simple async.

You can do USB directly on the ESP32, but boot loader won’t support flashing over USB.

CP2102 is dirt cheap. Less than US$1 in bulk. FTDI similar pricing. Both are transparent (no code required) and simply bridge async to async-over-USB.

Regards, Mark.

> On 26 Sep 2017, at 1:30 PM, HONDA S-2000 <s2000 at audiobanshee.com> wrote:
> 
> I'm very surprised that a driver must be installed. In my experience, most hardware implements the USB Communications Device Class standard, and therefore does not need a driver with OSX. Does anyone know why Silicon Labs didn't just implement the standard CDC protocols?
> 
> I assumed that the ESP32 processor would have a USB peripheral that would host the protocol, and therefore the OVMS v3 firmware would be in control. I guess I didn't look closely enough.
> 
> What does the CP2102 cost in relation to something like a PIC with USB? Sorry for the question.
> 
> Brian
> 
> 
> On Sep 24, 2017, at 11:42 PM, Mark Webb-Johnson <mark at webb-johnson.net> wrote:
>> 	• The Silicon Labs driver for OSX seems pretty flaky. Linux seems much better, and I haven’t tried Windows. On OSX, I had horrendous problems with the v5 drivers crashing my whole machine (Sierra 10.12). In the installation package, there is a “Legacy MacVCP Driver” directory containing the older 4.11.2 version - using that older version at least works without crashes, but has one known issue. If you ‘make monitor’ and are in the console to the board, then unplug the board, you get left with a /dev.tty.SLAB* device hanging around that messes up that one USB port and future ‘make monitor’ connections. Workaround is to power off the USB hub, and then everything cleans out nicely. If you are directly connected to your MAC’s USB port, then you seem to need to reboot the whole machine to fix the issue. Getting used to being careful to disconnect from the terminal before unplugging (or simply not unplugging - which was happening a lot when I was working on power optimisation, sleep modes, and external 12V power).
>> 
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