10 Nov
2013
10 Nov
'13
5:34 p.m.
On Sun, Nov 10, 2013 at 06:05:40AM -0500, Mouse wrote:
Depending on what you're driving with them, this
"conversion" may be a
no-op. AIUI 3.3V outputs normally swing rail-to-rail, and 3.3V is well
above the TTL "high" input threshold, so you can just feed a 3.3V
output directly to a TTL input, provided they share GND.
Yes -- I've had fine luck talking to 74LS using 74LVC parts (which are
impossibly wonderful -- cheap, low power, familiar pinouts, and wicked fast).
The only danger is that the rail-to-rail thing becomes much less true with
loading ... so ... don't load it! I.e. keep fanout (of outputs to 74LS)
to a minimum and everything will be groovy.
John Wilson
D Bit