3 to 5 volt conversion question.
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Atmel produces a lot of different SPI data Flash EPROM's. The old
versions from Atmel was using 5 volt on the I/O lines. But the new
versions are using 3 volt power as well as 3 volt on the output
lines. The input lines are still 5 volt compatible.
I tried to use a logic 74HCT14 smith trigger to raise the output
level. But the level was to low to trigger the smith. Could anybody
think of a better circuit/way to convert 3 to 5 volt?
Stein.
versions from Atmel was using 5 volt on the I/O lines. But the new
versions are using 3 volt power as well as 3 volt on the output
lines. The input lines are still 5 volt compatible.
I tried to use a logic 74HCT14 smith trigger to raise the output
level. But the level was to low to trigger the smith. Could anybody
think of a better circuit/way to convert 3 to 5 volt?
Stein.
Comments
(xx=pick the appropriate family) that you can power from 5 volts. That
should convert the level to 5 volt logic for you. You may need to use a
pull down or up resistor on the input to get over the threshold to trigger.
Or, as an alternative, a simple 2n3904 transistor switch can pull 5 volts to
low to drive additional gates. Power it with the 5 volt supply and trigger
it with the 3 volt logic. Be sure to tie the grounds from both supplies
together so that ground is the same potential on each. For total isolation,
consider an optical isolator but this requires more current to trigger.
jim
http://www.geocities.com/jimforkin2003/
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