Replacement for 74LS245

[joe_1]

I am using several of the 74LS245 which is an 8-bit transceiver.
I am trying to write to only one of them at any given time, so this means that I can enable only one at a time. But the problem is that the moment I disable the chip that I have already written to, all its output goes into an isolation state. I am looking for something that preserves the state of the outputs before the chip is disabled.

The 74LS245 is very simple. It has Port A which is an 8 bit input that I connected to the bus, and Port B which is the output bus.
The DIR pin is set Hi so that when the E is low, whatever on Port A is written to Port B.

As I said everything works OK, except that when I disable the chip (so I could write to the other 74LS245 chips), port B goes into isolation state.

If someone knows any other chip to use please let me know.

Thanks in advance.

 

[on1aag]

Hi Joe,

I am looking for something that preserves the state of the outputs before the chip is disabled.

The 74LS245 is very simple. It has Port A which is an 8 bit input that I connected to the bus, and Port B which is the output bus.
The DIR pin is set Hi so that when the E is low, whatever on Port A is written to Port B.

As I said everything works OK, except that when I disable the chip (so I could write to the other 74LS245 chips), port B goes into isolation state.

The 74LS373 and 74LS573 will do the trick but you gonna have to reverse
the enable command and keep the output control at a logical "0".

on1aag.

 

[Cabwood]

The '374 is an octal latch just like the '373, but edge triggered. Might I also suggest using 74HCT or 74HC families instead? Sure, you need to take care with static discharge, but the inputs are much lighter, and outputs are cleaner and stronger. And your power requirements drop like a stone.

 

[ericgibbs]

hi joe,
Q:
I am using several of the 74LS245 which is an 8-bit transceiver.

Are you using the 245 in its bi-directional mode?.. or are you looking for a
tri-state octal latch.

Do you have a drawing you could post?