Good day all- I'm new here, so please forgive me for reviving an old thread.

I discovered this thread while doing some research for my current project- I hope my reply here is relevant to the original post since I'm going in the opposite direction signal-wise.

I'm looking to control a 1980's era SP0256 speech synthesizer chip (1980's TTL) from a Raspberry Pi 2. As far as I can tell- I'm only inputting into the SP0256 from the Pi GPIO, I don't require any feedback data back into the Pi (if so I'd use the methods outlined above). Are there any issues with direct input from a Pi GPIO to TTL? More of concern- is there any risk of damage to the Pi if inputting directly to TTL?


Mod: link to other thread
https://forum.allaboutcircuits.com/...to-raspberry-pi-gpio-3-3v.166842/post-1477844

 

Good day all- I'm new here, so please forgive me for reviving an old thread.

I discovered this thread while doing some research for my current project- I hope my reply here is relevant to the original post since I'm going in the opposite direction signal-wise.

I'm looking to control a 1980's era SP0256 speech synthesizer chip (1980's TTL) from a Raspberry Pi 2. As far as I can tell- I'm only inputting into the SP0256 from the Pi GPIO, I don't require any feedback data back into the Pi (if so I'd use the methods outlined above). Are there any issues with direct input from a Pi GPIO to TTL? More of concern- is there any risk of damage to the Pi if inputting directly to TTL?


Mod: link to other thread
https://forum.allaboutcircuits.com/...to-raspberry-pi-gpio-3-3v.166842/post-1477844

I just did this same project. As long as you're outputting from the PI to the chip, you're fine.
I created an html with php that has all the preprogrammed phrases... i have the sp0256 chip that was designed for a clock. Supposedly it also has the phonemes in it to speak anything. I've yet to figure that out after having this chip since the 80s!