Boot Up Signal Circuit Design - Easily Signal or Configure Chips At Power On - Simply Put
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- Опубликовано: 25 авг 2024
- Sometimes you need to configure chips at power on or boot up time, like if you want to hold the reset pin of a chip at the start, or you want to perform some task or send a signal once the circuit has "warmed up" and is ready to go. Future videos will use this circuit to generate the control signal: This video shows how to make it.
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I love the idea of replacing microcontrollers with logic and methods like this! I'd love to see how to initialize a larger shift register (let's say 40 bits) with a very specific pattern using such a method. I'd imagine that to be somewhat hard to do. Looking forward to the upcoming videos!
Came across your channel by chance...brilliant videos, very well explained material!
This is something I’ve been looking for for a long time and I couldn’t figure it out. So important! Thank you!!
Found your page just now and it's great! You explain things very well and I appreciate the editing to definitive information. Subscribed and looking up that Discord.
Keep teaching us. You're good.
This explains what I needed, tried doing this myself without any knowledge, basically needed the hex inverter. But this caused me to think that this could also be applied to my other issue, that I have been really strugling to even think of what a solution to it is. I have a mcu that is in sleep mode, and I want to turn it on, when voltage goes >13v. So I figured a zener diode to trigger it, but that would just give me a high signal, and I need the mcu to go low to reset it, then go high again, and it's triggering that short pulse to ground that is causing me the problem.
Love. This video Thanks
great explanation, thank you.
Thanks
Brilliant
Well that was what I was looking for. Barely knew how to ask the question and you had a 26 minute video ready to answer it. I got the parts coming in for this to do it on a pet project now. But are there any ics available that just have all that built in already? It seems like such a common task
Just stumbled on your channel, and I'll be watching more of it to get teaching ideas! You give a nice, clear explanation of generating a power-on reset signal.
In place of that 27k resistor, another option is a 1N4148 backward in parallel with the charging resistor: dump the capacitor back onto the power supply rail at shutdown. (Or of course your JFET dump circuit, although availability of discrete JFETs in quantity is spotty since the Chipocalypse.)
What logic family are you using for those inverters? The gain you're seeing seems low for CMOS (although recently I've been mostly running 4000 series at 12V because I've got a bunch of opamps about and 12V handy, so I get faster transition times than 4000-series at 3.3 or 5 volts). Were you using a 4069 by any chance? Those are only singly-buffered, which makes them SLOW (and also gives them a really weak drive capacity). A 4049 would give you a much cleaner transition - but watch out, the 4049 pinout is weird. 74HC04 would also be an option, if I recall correctly.
You made a remark in passing about the Schmitt trigger not giving you inverted signals. Huh? CMOS 40106 or 74HC14 are hex inverting Schmitt triggers. I'd probably use one or two 74HC14 stages in this circuit and have four or five more Schmitt triggers available for cleaning up pushbuttons or whatever. Yeah, 40106 is slower than 4049 but for this stuff it doesn't matter.
Great refresher on Power On Reset. I use the DS1233. Check out the data sheet: datasheets.maximintegrated.com/en/ds/DS1233.pdf
So, is there a video of how initialize a shift register by this signal?
Why not just use a 555 as a monostable? Roughly the same number of components. 🤷♂