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December 7, 2011
about 3 years ago
According to the ATmega328 datasheet, Vih is 0.6Vcc at Supply voltage of 5v.
So Vih in my case is 3v.
I’m probably not going to find a datasheet for an iPhone 3G (my 3.3v device) so i’ll just have to try it and find out!
Thanks for your help :)
Why can’t I just use a simple resistive voltage divider with 1.5k + 3k in series, take the output across the 3k resistor to get 3.3v?
That would be used on the TX line of the 5v device.
Is it because the +3.3v on the other device’s TX isn’t a strong enough logic high for the +5v device’s RX?
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