Well, it is nice that you made a new PCB for the DS1307, but there are already PCB's for it. Than there could be a reason to make a new PCB, if and when there is an improvement, such as the extra one second clock puls. It can be used to give a signal for something. Maybe the puls is only there if the clock is set and running, maybe it is only there when the clock is on power, maybe the puls is always there. Things I would have changed are, the direction of the board, make the connector at the slimmist side, then it can be used economically on breadboards, it does not use much space. The board then can also be used in existing other designs. If it would be a point to completely reset everything by taking out the battery, then something could be added, like a switch, if it is going to be stored, the battery should not be connected, then the clock would run and use energy. The extra switch would be a new feature. Furthermore an LED could be added with a push button, to test if the battery is still having power. I know that there are also RTC chips with a build in alarm function. The Japanese Kyocera has one. If the alarm is set, a signal is giving on a specific time, on a connection on that specific RTC chip. This can be used for instance to switch on the main power supply to start up the computer early before work. There are many sorts of crystals, most have two connections, some have something extra and they have two extra power connections. I would make the PCB in such a way that all kind of crystals could be used. From the cheap ones of Chinese toy watches to the expensive crystals made for precision equipment. Big ones and small ones. It is well known, all over the world, that worthless crappy Chinese crystals are very unreliable. Often every day gains a few seconds or the opposite. To make a clock run perfectly two of those cheap crystals could be used and the difference between the two crystals could be averaged, then the RTC would become twice as accurate. It would be so nice the beat the Chinese at their own game.
Thanks for your feedback, I don't get much and it's appreciated. You've given me a lot to think about there. You're right there are other boards available, I mainly just wanted some practice at designing PCBs. I probably should have put more thought into it, like you say about adding an extra feature. I like the idea of a battery test switch and LED. Also good point about putting the connector on the short edge to make it more breadboard friendly.
@@SteveRaynerMakes Perfect! Next time it will be a MkII board, the enhanced version, new and improved. Constant innovation is what made the Japanese electronics industry great and conquer the complete American electronics industry.
The PCB was designed in EasyEDA. I can export as PDF, PNG or SVG if any of those are any good to you. The PDF and SVG look quite good, but the PNG version looks poor. I also have spare PCBs that I can post for free if you are in the UK.
You really need to use a hex calculator. I think the one you were using on your Mac might do hex already. I’m using an app on my iPad and iPhone which makes it easy. Just type in the number $30F7 (from your listing) in hex mode and then switch to decimal mode. =12,535 Done. None of this nn shift left 8 times + mm BS.
part list would be nice !
Thank you for your work, very well explained!
A bit of hot snot (as we call it) should help keep the XTAL from flapping about.
Well, it is nice that you made a new PCB for the DS1307, but there are already PCB's for it. Than there could be a reason to make a new PCB, if and when there is an improvement, such as the extra one second clock puls. It can be used to give a signal for something. Maybe the puls is only there if the clock is set and running, maybe it is only there when the clock is on power, maybe the puls is always there.
Things I would have changed are, the direction of the board, make the connector at the slimmist side, then it can be used economically on breadboards, it does not use much space. The board then can also be used in existing other designs. If it would be a point to completely reset everything by taking out the battery, then something could be added, like a switch, if it is going to be stored, the battery should not be connected, then the clock would run and use energy. The extra switch would be a new feature. Furthermore an LED could be added with a push button, to test if the battery is still having power.
I know that there are also RTC chips with a build in alarm function. The Japanese Kyocera has one. If the alarm is set, a signal is giving on a specific time, on a connection on that specific RTC chip. This can be used for instance to switch on the main power supply to start up the computer early before work. There are many sorts of crystals, most have two connections, some have something extra and they have two extra power connections. I would make the PCB in such a way that all kind of crystals could be used. From the cheap ones of Chinese toy watches to the expensive crystals made for precision equipment. Big ones and small ones.
It is well known, all over the world, that worthless crappy Chinese crystals are very unreliable. Often every day gains a few seconds or the opposite. To make a clock run perfectly two of those cheap crystals could be used and the difference between the two crystals could be averaged, then the RTC would become twice as accurate. It would be so nice the beat the Chinese at their own game.
Thanks for your feedback, I don't get much and it's appreciated. You've given me a lot to think about there. You're right there are other boards available, I mainly just wanted some practice at designing PCBs. I probably should have put more thought into it, like you say about adding an extra feature. I like the idea of a battery test switch and LED. Also good point about putting the connector on the short edge to make it more breadboard friendly.
@@SteveRaynerMakes
Perfect!
Next time it will be a MkII board, the enhanced version, new and improved. Constant innovation is what made the Japanese electronics industry great and conquer the complete American electronics industry.
Thank you for this good introduction to the layout design and the chip.
Glad you like it!
How I draw the local ground plane under crystal's region ?
Instead of using a crystal oscillator could I use a 555 timer to produce an 32kHz ac current that goes into the x2 pin?
Friend, is it possible to connect a capacitor replacing the battery? Can a capacitor hold the chip's data for a few if the power fails? Thanks.
I don't really think that would work. The capacitor would discharge too quickly.
what about accuracy of this RTC..... RTC1302 drift time after few hours and get ahead 4-7 minutes after every 24 hrs.
That's a very valid point. An RTC that drifted that much would be useless. I will have to measure this a do a follow up video.
Wow if it drifts that much it’s time to go back to a sun dial.
Can I download your pcb design? Is it in JPEG format? I want to create pcb at home.
The PCB was designed in EasyEDA. I can export as PDF, PNG or SVG if any of those are any good to you. The PDF and SVG look quite good, but the PNG version looks poor. I also have spare PCBs that I can post for free if you are in the UK.
You can find PDFs here. github.com/srayner/ds1307
@@SteveRaynerMakes Thank you.
You really need to use a hex calculator. I think the one you were using on your Mac might do hex already. I’m using an app on my iPad and iPhone which makes it easy. Just type in the number $30F7 (from your listing) in hex mode and then switch to decimal mode. =12,535 Done. None of this nn shift left 8 times + mm BS.
you're right, i could have just typed in 30F7 and converted to decimal