inverted TTL == negative logic ?? - Electronic Circuits Projects Diagrams Free

hani_a · 20th April 2004, 08:10 AM

Hello people,

does anyone know for sure if inverted TTL means negative logic? if not, can one explain to me what inverted TTL..

Thanks!

**Nigel Goodwin** · 20th April 2004, 09:20 AM

Quote:

Originally Posted by hani_a

Hello people,

does anyone know for sure if inverted TTL means negative logic? if not, can one explain to me what inverted TTL..

Thanks!

It depends on the context, if low is a '1' and high is a '0' then that's inverted logic - but in many TTL circuits this will occur at various points within the circuit anyway.

I would only consider it negative logic if the entire design worked that way.

weegee · 20th April 2004, 04:14 PM

if this is in response to the other post then inverted TTL is the output from a microcontroller for controlling serial devices, so when something is sent from the controller to the recieving device - the signal is the opposite of what a full RS232 serial device would show - eg a '1' on RS232 is actually -12v, and a '0' is +12v, although if you are dealing with inverted TTL in this sense a '1' is +5v and a '0' is 0v - This is the way that many serial devices work to negate the effect of having to use MAX232 ect. to provide the +12v and -12v for full RS232 spec.

I hope that makes sense to you :?

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20th April 2004, 08:10 AM	(permalink)
hani_a	inverted TTL == negative logic ?? Hello people, does anyone know for sure if inverted TTL means negative logic? if not, can one explain to me what inverted TTL.. Thanks! __________________ i\'m actually a novice in the robotics field and would love to get help to lunch my projects..

20th April 2004, 04:14 PM	(permalink)
weegee	if this is in response to the other post then inverted TTL is the output from a microcontroller for controlling serial devices, so when something is sent from the controller to the recieving device - the signal is the opposite of what a full RS232 serial device would show - eg a '1' on RS232 is actually -12v, and a '0' is +12v, although if you are dealing with inverted TTL in this sense a '1' is +5v and a '0' is 0v - This is the way that many serial devices work to negate the effect of having to use MAX232 ect. to provide the +12v and -12v for full RS232 spec. I hope that makes sense to you :?