Zilog used to sell a $40 development board using a Z80 Encore! chip running at 18 MHz. Zilog was bought by LittleFuse in 2017. The development board, with reduced capability, is now $280. I'll be following your project with interest. Great to start at the beginning. It took me a few decades of using the 555 to realize that it is just a Schmitt trigger with a variable trigger point. Please, please, please don't use that crappy CZcams "music" behind your narration. Your presentation is excellent and it's so pleasant to hear a voice a capella.
Some seriously under rated information here. I've messed around with one of those arduino children's kits for about a year now and I'm starting to dive deeper into electronics. I was happy your video hit my feed. It's not information I thought I'd care to watch, but it's been an extremely interesting video. Thank you! Can't wait to get to the point of using the information.
Ah, you're going to do not just a "here's my computer" video but a "here's my computer and why it's designed that way" set of videos, excellent. (Also, there's no link to your oscope in the description)
No, this is everything I wished I had know before I started. Hopefully this will help people wishing to build one of their own. Thanks for the heads up! I know I forgot something. It is there now.
Yes, this series is starting from scratch and ending with a fully functioning computer. And I am not just glossing over the details. I want this to be what I was looking for when I started
Very interesting ! Question, if you were to just use the 555, would it be able to send out a 1Mhz signal and could it drive the system clock bus for the rest of the system?
Interesting stuff , just a question - how does the capacitor discharge in the first clock circuit. When the input is 1 producing a 0 on the output does the current flow get drawn from the positive side of the capacitor through the resistor then through the IC itself to ground?, Just a little lost on the discharge side of things, looking forward to following this project.
I am so sorry I took so long to reply. Somehow I missed this comment. I have created a quick video to explain how this capacitor works. czcams.com/video/yqmq9fOzZMY/video.html Thank you for the question!!
It is a variable to take into account different chip families, etc. For example, a 74AC14 would have a different value because it switches a lot faster than the HCT. I could have, and probably should have, adjusted that when I got 4Hz instead of 5Hz, but for the video it was close enough.
I believe that is due to the switching point of the input. The device switches to a high state at approx 2/3 of the input voltage. But, looking at some data sheets I see f = 1/ (K * R * C) where K varies from slightly above 1 at 4.5V to around 0.82 at 5.5V.
Zilog used to sell a $40 development board using a Z80 Encore! chip running at 18 MHz. Zilog was bought by LittleFuse in 2017. The development board, with reduced capability, is now $280.
I'll be following your project with interest. Great to start at the beginning.
It took me a few decades of using the 555 to realize that it is just a Schmitt trigger with a variable trigger point.
Please, please, please don't use that crappy CZcams "music" behind your narration. Your presentation is excellent and it's so pleasant to hear a voice a capella.
Thanks for the feedback!
Definitely no music behind me. That is too distracting when watching something like this!
Some seriously under rated information here. I've messed around with one of those arduino children's kits for about a year now and I'm starting to dive deeper into electronics. I was happy your video hit my feed. It's not information I thought I'd care to watch, but it's been an extremely interesting video. Thank you! Can't wait to get to the point of using the information.
Thank you! Good luck, and most of all, have fun!
Ah, you're going to do not just a "here's my computer" video but a "here's my computer and why it's designed that way" set of videos, excellent. (Also, there's no link to your oscope in the description)
No, this is everything I wished I had know before I started. Hopefully this will help people wishing to build one of their own.
Thanks for the heads up! I know I forgot something. It is there now.
Almost forgot, will you be putting out a video on how to create the backplane and other boards from scratch ?
Yes, this series is starting from scratch and ending with a fully functioning computer. And I am not just glossing over the details. I want this to be what I was looking for when I started
@@Pony80 Awesome ! That sounds exactly like what I have been looking for !!!!
I need a good 4 ch scope. On the cheap. Any suggestions for a fellow hobbyist?
I do not. I wanted a 4 channel, but got the two channel because the price point was so much higher for the four channel.
Very interesting ! Question, if you were to just use the 555, would it be able to send out a 1Mhz signal and could it drive the system clock bus for the rest of the system?
would be at upper range of 555. "maybe"
I foresee an experiment coming up!
Interesting stuff , just a question - how does the capacitor discharge in the first clock circuit. When the input is 1 producing a 0 on the output does the current flow get drawn from the positive side of the capacitor through the resistor then through the IC itself to ground?, Just a little lost on the discharge side of things, looking forward to following this project.
I am so sorry I took so long to reply. Somehow I missed this comment. I have created a quick video to explain how this capacitor works. czcams.com/video/yqmq9fOzZMY/video.html Thank you for the question!!
Where does the 0.67 for HC14 come from?
It is a variable to take into account different chip families, etc. For example, a 74AC14 would have a different value because it switches a lot faster than the HCT. I could have, and probably should have, adjusted that when I got 4Hz instead of 5Hz, but for the video it was close enough.
I believe that is due to the switching point of the input. The device switches to a high state at approx 2/3 of the input voltage. But, looking at some data sheets I see f = 1/ (K * R * C) where K varies from slightly above 1 at 4.5V to around 0.82 at 5.5V.