On 4/3/06, Peter Gargano <peter@techedge.com.au> wrote:
I have the reverse concern - Driving AVRs from parts designed to be
used with TTL. Most AVRs (eg Mega-168) have a 0.6VCC spec. on VIHmin
meaning 3.0 Volts when run at 5.0 Volts (well, actually worse case is
0.6 x VCCmax which may give VIHmin of 3.15 Volts).
Right but that's also when loaded to the max current spec for a high output pin.
Many parts you may want to interface to an AVR have a VOHmin of 2.4
Volts - meaning they are not guaranteed to drive the minimum required
3.0 Volts.
Again, when driving a full spec load.