Hello - I'm posting in beginners because that's what I am and since I found a few other posts here around the same type of topic, I figured it was the better option than bugging those who know better than I.
I got a few W27C512 very cheap and figured I would give it a whirl to limit the number of chips needed for some of my plans. Reading the datasheet (
https://media.digikey.com/pdf/Data%20Sheets/Winbond%20PDFs/W27C512.pdf) gave me more gray hair than it should though. I had not realized I needed different voltages to overwrite data. So my first step is to create a reader and then add a writer component to it. I don't think spending $300+ to do that is worth it, and I think this will be plenty of a challenge to help me grow a bit more into this. But I have a few questions.
I have an arduino mini lined up and ready to do this.
1) How do I protect the 5v circuits connected to A9/OE when I apply 12 or 14 volts? Not sure how to design a "buffer" around this.
2) I plan on using two simple 74HC595's for addresses since well the arduino doesn't have enough data lines to do both data and addresses. I don't see anything preventing this from happening. Most of the time limits are minimum, and the max limits seems to all be around erasing which isn't using addressing.
3) Typical newbie question: Is it best to step up voltage or step down? Should I look for a 14 volt supply voltage and step everything down, or step up from 5v? I think stepping up is best as that's the typical operation voltage. Only during erase/write is higher voltages needed.
4) I'm totally lost on section 10 AC Characteristics. What is this telling me? What's the diagram supposed to do - is that what's in the chip, or something that's expected to be in the circuit using the chip?