Realizing I don't have a good idea of how to draw a schematic in KiCad that uses either a 30 or 32 pin storage device. I appreciate the pinout diagram that kernelthread posted, and I have an idea of how I'd lay out the traces if I was just doing a PCB layout, but I'd like to actually capture and ...

After a lot of thinking, I am pretty convinced I am going to switch the expansion connector from 1x40 to 2x25. I wrote up the new bus layout over here: https://github.com/Individual-Solid/f1microcomputer/blob/main/s50Bus.md. A majority of the differences from the 1x40 pinout are...more ground lines ...

No, I don't notice any problem with these latest traces. SYNC should go high for one entire cycle at a time -- never a fraction of one cycle. And yet, fractional-cycle glitches is what the previous traces seemed to show.

Thanks for double checking for me! I'm getting pretty quick at setting up ...

It all works. [...] this revision has fully come to life. Wow -- really? I'm glad, of course. But you seemed to have some pretty strange glitches on SYNC. These could perhaps be an artifact of your 'scope setup, and have no functional implications. But unless these can be eliminated or at least ...

Well that's just a bit weird. Have you already pulled the reset LED out of the circuit to do this testing? That's the one thing there that's at all unusual. If so, I'd be tempted to lift the DS1813's reset pin and measure it independent of the rest of the circuit to see if there's something else in ...

So, the remaining issue is that the board is held low in reset for over six (6!) seconds on initial power up. If this is a DS1813 with the 5% trip point, power needs to get to above 4.62V before coming out of reset. I suppose I should just put CLK, Reset, Sync, and "5V" (at the bus) on my scope ...

Just 'cause this reset light sounded like a neat idea, I wired up the same circuit to my RC6502 Apple 1 clone SBC†
So what you want to do there, with that original circuit above, has been shown work. I am guessing that it's something else in your setup.
†Boy am I getting tired of typing all that ...

Yes, this is actually a hardware post. I'm thinking about bootloaders. A "small program that places [another program] into memory".

There are bootloaders that are programmed into (EEP)ROM and then use an interface to load the target program. These are often integrated into a Monitor program, but I ...

The Web Standards Consortium are currently in the middle of trying to establish a new file access api, to allow browsers to have consistent and secure access to user files - unfortunately, Firefox and Safari are struggling to keep up with the changes in standards, so writing for them involves using ...

This is the reset LED circuit that was definitely never going to work:
It is correct. The anode is going towards the +5V, and when the reset line goes low, the diode will conduct and light up. The only problem might be if the load is too heavy for whatever is supposed to pull the reset line down ...

This is the reset LED circuit that was definitely never going to work:
schematic2.png

Now, I had to try out of curiosity. I reversed the LED, so power would actually flow through the diode. For my first few tries, the LED worked as expected, it illuminated as the board was in RESET and turned off ...

Oh, one thing of note. The Reset LED doesn't illuminate when the board is in /RESET. looking back at the schematic, it looks like I will have to solder it backward to give it a chance to illuminate! For the revision I will probably switch to using the last gate on the '00 to provide a RESET (high ...

Back to the main board -- It arrived, and it works!

IMG_0706.jpg

I got the onboard CA1 LED blinking within a day. I initially soldered a can osc directly to the board and it was not clocking the CPU (no action on Sync or anything else). Once I pulled the can up and pushed a clock signal down the ...

Very cool build! We've got an [link=http://forum.6502.org/viewtopic.php?f=4&t=6730]ongoing thread[/link] about how to assign pins on a 40-pin backplane for 6502 builds. If you're interested in sharing pinouts, you may have figured out something we haven't yet!

I have a similar thermal printer that ...

Folks using the FT254RL (in UM form or just the chip) - how are you address decoding the control lines? Particularly the TxE and RxE. I'm currently struggling over a compact circuit over on page three/four of this thread.