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by AHorneffer
Thu Dec 06, 2018 2:08 pm
Forum: V-USB
Topic: 1k5 k pull-up on D-
Replies: 9
Views: 10367

Cautionary tale (Re: 1k5 k pull-up on D-)

Hi blargg Thanks for the explanation, I now understand the problems I had. Maybe as a cautionary tale for others (Even though most of us probably only read that when it is too late, like I did): when choosing the zener diodes for my latest project I didn't pay attention to the power rating of the di...
by AHorneffer
Thu Dec 06, 2018 1:39 pm
Forum: V-USB
Topic: ATmega328p with internal RC oscillator?
Replies: 7
Views: 1124

Re: ATmega328p with internal RC oscillator?

Hi

lgberro wrote:I am trying to make atmega328pb run with internal oscillator at 12.8MHz. We could share our achievements.


A bit late, but just FYI: I gave up trying to use VUSB on the ATmega328p with the internal oscillator.
I use it with 12MHz or 16MHz crystals.
by AHorneffer
Thu Dec 21, 2017 1:51 pm
Forum: V-USB
Topic: USB-RFM70 RF transceiver adapter
Replies: 2
Views: 627

Re: USB-RFM70 RF transceiver adapter

Nice.

I was just wondering: do you need an m328? Wouldn't a smaller MCU work as well?
by AHorneffer
Thu Dec 21, 2017 1:36 pm
Forum: V-USB
Topic: ATmega328p with internal RC oscillator?
Replies: 7
Views: 1124

Re: ATmega328p with internal RC oscillator?

Did you also try the 16.5 MHz version? If I look at the F vs. OSCCAL drawing on p. 607 of the datasheet* with split OSCCAL and you use the default starting value of 128 you're in the upper half that starts with 6..6.5 MHz (-> clock frequency 12..13 MHz) and grows. [I guess you mean figure 33-39 of ...
by AHorneffer
Wed Dec 13, 2017 11:30 am
Forum: V-USB
Topic: ATmega328p with internal RC oscillator?
Replies: 7
Views: 1124

Re: ATmega328p with internal RC oscillator?

I understand that V-USB requires a precise clock. But for micronucleus it doesn't have to be stable for long times, only a minute or so, then all the transfer is done. I understood it that the 12.8 MHz mode was made to work with the internal RC oscillator of some of the chips. So I'm wondering if it...
by AHorneffer
Sun Dec 10, 2017 4:40 pm
Forum: V-USB
Topic: ATmega328p with internal RC oscillator?
Replies: 7
Views: 1124

ATmega328p with internal RC oscillator?

Hi I'm working on using micronucleus with the ATmega328p. It works fine with an external 16MHz crystal, but when I try using the internal RC oscillator, then the host doesn't recognize the USB device. In the syslog (on Ubuntu Linux 16.04) I get: Dec 10 15:33:09 cypresse kernel: [17708.254022] usb 1-...

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