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Any 74-series chips that can do this ... ?

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Tickled_Pink

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In my collection of ICs I have some MAX7301 I/O expander chips. Unfortunately they're in a SOIC package which I can't use at the moment. So I'm looking at creating a suitable alternative using some 74-series ICs.

Some of the candidates I've looked at so far have included the 74259 and 74166. Both these are pretty good when it comes to expanding the number of output pins. In one quick design I even used the 74259 to increase the number of 'control' outputs from 4 to 16 to control a bank of four 74166 ICs. The 74166 would then receive serial output from two of the other four original outputs available to me ... but then I realised I misunderstood what the 74166 actually did.

What I'm really looking for, I suppose, is a shift register where the outputs and inputs can be reversed ... i.e. it can receive a serial input and provide a parallel output, or the other way around (parallel to serial). Then again, I suppose I could fiddle around with some of the other ICs around, but it would increase the part count - which is something I'm trying to avoid.

Any ideas?
 

kinjalgp

Active Member
There are few other I/O expanders like 82C43, 82C55. You can use it along with any microprocessor/microcontroller or PC's parallel port.

You didn't mention what thing controls your expander ICs. uC/uP or PC?
 

Tickled_Pink

New Member
It's actually an Atari 800XL computer. The direction inputs on the two joystick ports can be used as output ports as well. As I can program the machine in 6502 assembly, it's an ideal test unit for any circuits I build before moving the circuits over to a microcontroller.

However, the initial project is designed primarily for the Atari to build a ROM cartridge programmer/development kit for this machine (and possibly others later).

I've just been looking at the 74HC299. If I'm reading the datasheet properly, this (along with a some 74259 ICs) will do the job ... unless you can think of a problem or something better :?:
 
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