Some digital signal procesing [HELP!]

[ckdur]

Hello All!!!

I have some digital inputs working 0V (for 0) to +12V (for 1).

1. I understand that I can't use TTL gates/flip-flops. What's the remplacement in CMOS? I use the following TTL's: 74LS32 (or another multiple input OR gate), 74LS74 (flip-flop)

2. I need to use 1-0 clock for flip-flops, I only know the standard 555 1-0 clock. What kind of clocks I can use? 555 are ok for +12V-0V? And witch time-intervale / frequency I can work?

3. The respective results (other digital outputs) obviusly will work with 0V (for 0) to +12V (for 1). I need to transform this to 0V (for 0) to +5V (for 1). What's the best (and the most cheap :razz form to do this?

Thank yoy very much! your help will be hopeful for my little project!

 

[zorro]

Hi ckdur,

1. I understand that I can't use TTL gates/flip-flops. What's the remplacement in CMOS? I use the following TTL's: 74LS32 (or another multiple input OR gate), 74LS74 (flip-flop)

The ooold metallic-gate CMOS series 4000 and 4500 allow that logic levels (from 0-5 V to 0-15 V).

2. I need to use 1-0 clock for flip-flops, I only know the standard 555 1-0 clock. What kind of clocks I can use? 555 are ok for +12V-0V? And witch time-intervale / frequency I can work?

555 can manage that levels if you want a low-frequency RC clock generator. But a crystal oscillator made with an inverter gate could better for you.

3. The respective results (other digital outputs) obviusly will work with 0V (for 0) to +12V (for 1). I need to transform this to 0V (for 0) to +5V (for 1). What's the best (and the most cheap :razz form to do this?

You could use voltage dividers (cheapest) or logic level converters (several gates included in one IC package).

Regards

Z