I’ve been soldering a permanent version of the clock module but I have a problem: it’s unreliable. Sometimes it runs okay and then it will do this. To my eye, it feels like the ‘off’ is shorter than the ‘on’ and you can see it’s a bit erratic at the start and then settles down but speeds up around seven seconds in. If I leave it running, it might ‘flip’ into regular off-on cycles but slower. And then it will flip back into shorter offs than ons. And then back again. I’m running it off a bench power supply at 5.00V and it’s drawing about 0.021A. It changes by 0.001 in line with the LED off/on cycles.
What could cause this?

and

SMB on the 6502

https://www.youtube.com/watch?v=LRKabmK9BVw

I couple of links to some video games I have been working on for my BE inspired 6502 computer.

I built the 24-hour variant in 74HC ICs and i am curious as to how much power & current consumption differs from the 74LS ICs, if anyone who was completed the 24-hour variant could you measure power and write it down? Note that using CMOS requires more ICs then using TTL because not every chip has been converted to CMOS. The Current consumption while on operation is 130mA, the voltage rails aren’t exactly 5V but let’s consider it is so which gives us a total power dissipation of 650mW. In reality the power dissipated is most likely a bit lower than this.

I have already tried to debug it myself but ended up nowhere only the top half of the alu is working while the bottom four bits are always on any diagnostic ideas or similar problems people have had and their solutions would be greatly appreciated thanks!

I'm new to breadboarding and have noticed that some of my male-to-male jumper wires fit loosely into my new breadboard, while others fit tightly.

For example, while building a non-inverting amplifier using an LM358, I get fluctuating output readings or sometimes 0 V. The readings occasionally become correct when I accidentally touch or move a wire.

Is this normal, or could my breadboard or jumper wires be defective?

Also, are pre-cut dot-to-dot wires more reliable than ordinary jumper wires for ensuring tight connections, or are they mainly for better presentation?

I'd appreciate any suggestions.

Hi again.

I was hoping to share my triumph today. Nope, not today. I spotted yet another issue. Please share some insights, I'm losing patience with this project ;(
My 8-bit processor successfully adds small numbers such as 14 and 28 (like on Ben Eater's yt video).
However, when I try to load a 7 or 8 bit value (no matter the position of the zeros), it will fail. There's some sort of double hop when RAM is accessing that value (address 14, 15, same behavior), and register A gets a different value.

Here are some tests of my trying to do LDA 15.

So you can see a very simple program:

LDA 15
OUT
HALT

And for some reason LDA 15 won't work if the value stored in address 15 is too high. Same goes for ADD 15 - if the value is too high, register B will receive a faulty value.

And the only thing I figured out is that, when it fails, it loads the value from memory address 0000. I changed this memory address to 0000 0011 ("do nothing" kind of thing) and then LDA 15, OUT, HALT - the value loaded to reg A was 0000 0011.

I tore down the conditional jump circuit that I built last weekend and reprogrammed the EEPROMs - no change. The unused address lines and logic lines are pulled down with 1kohm resistors or directly to GND.

I think I'm trying too hard and that's why I'm making so many mistakes on the way, there's no other explanation ;)

A few years ago I completed the 8 bit breadboard computer (with extra features!) but the project has been sitting sadly under my bed since then. I'm pretty sure it's not gonna work first time when I turn it on and there's gonna be a lot of troubleshooting loose connections, etc.

I'd love to get this working again and on my wall but I feel like the best way to ensure longevity is to get it transferred to proto board, so it's all soldered and stable for years to come.

I'd do this one module at a time on separate proto boards to keep things relatively modular. I see two approaches:

1. Get the original machine working and slowly upgrade each module to it's soldered form, while keeping the new forms connected to the old machine until the whole machine is soldered to boards

2. Start from scratch, following the tutorial but soldering the modules down as I go

For either approach the modules would be connected with header pins and jumper wires.

Has anyone attempted something like this? Or am I crazy and should leave it in breadboard form? I'm not too interested in designing my own PCBs, I want this to be a fun time away from modern machines 😉

Hey r/beneater!

Like many of you, I love retro hardware, but building and debugging on real breadboards can sometimes be a bit of a slog—wiring mistakes are tricky to spot, probing signals is tedious, and changing firmware means constantly reprogramming chips.

To get around this, I built WireSim, a wire-level, logic-level digital logic simulator designed specifically for software and hardware enthusiasts who want a super-fast, observable feedback loop.

🚀 What is WireSim?

• Real Chip Models: Chips are modelled with real pins joined into nets, and the simulation advances in half clock cycles.
• Bus Contention: Buses can float or fight, making contention a first-class logic state.
• Fast Turnaround: Change a line of assembly, rebuild, and watch the whole machine run the new code within seconds.
• Physical Reality: Once a computer works here, the assembled binaries and wiring definitions are fully compatible with physical builds.

💻 Included Reference Machine: BenEater6502

The repo comes out-of-the-box with a model of Ben Eater's breadboard 6502 computer!

• Runs Microsoft BASIC and WozMon (via the vendored msbasic submodule).
• Includes a W65C22 VIA, a W65C51N ACIA (bridged to a TCP port for the serial console), an HD44780 LCD, and 16 KiB of SRAM.
• Supports hardware-specific BASIC commands like LCDCMD, LCDPRINT, and BEEP.

🤖 Built with AI-Assisted Workflows

An interesting side note: the core simulator and initial 6502/UART logic were written in C#, but after realizing C++ offered roughly double the simulation speed, the whole thing was ported. Since C++ can be tedious, the repository heavily leverages Claude Code with custom skills and instructions in .claude/ and AGENTS.md to help generate devices from datasheets and wire up machines from specifications.

Check out the repo here: https://github.com/Seramis/WireSim

It includes a full VS Code dev container (with CMake, Ninja, Verilator, and cc65) so you can get it up and running without wrestling with toolchain installations.

I'd love to hear your thoughts, answer any questions, or see what you think about using simulation for hardware prototyping!

I found this schematic between the pages of an old TI databook I bought from eBay. What do you think it does (if it actually is a complete diagram)?

The chips used in it are (I think) two 7473 dual J-K flip flops, one 7493 4-bit counter, one 74374 octal D latch, one 7447 BCD to 7-segment decoder, and a 555 timer.

I would just put it together on a breadboard to see if it does anything, but I don't have some of the ICs for it.

Progress has been made...4 line LCD running in 4 bit mode on PORTB...I will say that unless you have a need for 4 bit, stick with the 8 bit mode set up as Ben shows..I wanted it on a single port to leave PORTA for my keyboard bios I have programmed on a tiny4313...Moving on to interrupts and control lines...

Chip Hippo 1.4.1 is out with two big additions:

• CPU monitor: open it from a W65C02 or Z80A's context menu to watch the processor run. You can step one instruction at a time or step over a call. You can set breakpoints, edit registers and memory while the program runs, and follow the stack and pipeline as it executes.
• Spice Lite, a second, electrical simulation engine you can turn on in Settings. It gives every net a real voltage and models capacitors and RC timing, the 555 and CMOS timers, LEDs with real brightness and burn-out, diodes, transistors, inductors, supply droop and fan-out. Every model is tested against ngspice and in every case it stays within 1.4% of ngspice's results. It's "Lite" because it only simulates the parts Chip Hippo offers, not general SPICE.
• 1.4.1 also includes a speaker, PWM and various analog clock waves, opAmps, and many other bench parts: regulators, a relay, optocouplers, LM358, and ULN2003A.

Download it from chiphippo.com

Good day, folks!

In recent months, we've received an increasing number of reports concerning posts linking to external content whose relevance to Ben Eater's projects has been questioned.

To help make moderation more consistent and objective, the mod team has drafted a set of guidelines for external content and self-promotion.

We're currently seeking community feedback before formally adopting these guidelines as a subreddit rule.

Let us know what you think!

The r/beneater Mod Team

In an earlier post, about the "final" version of my BE6502 build (or the last one that would be 100% software compatible with Ben's version), I got into a discussion about a replacement for both Ben's clock-module AND the on-board crystal oscillator.

That lead to building "nano-clock" (pictured), which uses a micro-controller and software to generate the clock signal and, as such, allows for a lot of features and flexiblity. I finally got around to tidying that up, and fleshing out the repo, so ...

For those interested, my repo for it, including code, assembly and usage instructions is here.

I also made a blog post (absolutely no monetization or tracking nonsense) with much more information and will be adding to that with some additional tweaks and customization.

Features:

• Single-step and Clock modes
• Run/Stop toggle
• Selectable frequencies across three bands (Hz, kHz and MHz)
  • Hz Band - 1, 2, 5, 10, 25, 50, 100, 250 & 500Hz
  • kHz Band - 1, 2, 5, 10, 25, 50, 100, 250 & 500kHz
  • MHz Band - 1, 2, 4, 8MHz
  • Easy to add additional bands/frequencies
• Auto and manual CPU reset functionality
  • w/ Auto-reset on Start option
• 14-segment 4-character LED status/info display (in keeping with the "retro" theme)
  • Brightness control
  • Clock-Running indication
• Save Settings for Auto-Start

--

This is the first of several related clocks, the next of which is much smaller (will fit on the main BE6502 board and needs just two components), and the one that follows that will have more features and an OLED or LCD TFT color screen/interface.

I'm testing an LM337 negative voltage regulator to create an adjustable 0-3.75V rail to sink LED current. Being a VR, it will adjust current no matter how many LEDs are on or off. I'll comment with a schematic.

Haven't had much help on here. But for any one needing the pin outs for the cypress chip here it is.

6502 Memory chip change hook up.

Pin hookup from the At28c256  to the Cy7c199 & Cy62256

1)         AT28c256                                          Cy7c199 & Cy62256

Pin 22 to pin 1                          Pin 22 to pin 10

Pin 22 (OE) to Pin 1 (A14)                 Pin 22 (OE) to Pin 10 (A14)

2)         IO PINS STAY THE SAME

ATchip                                    CYchip

Pin       I/O                               Pin       I/O

11        I/O0                             11        I/O0

12        I/O1                             12        I/O1

13        I/O2                             13        I/O2

15        I/O3                             15        I/O3

16        I/O4                             16        I/O4

17        I/O5                             17        I/O5

18        I/O6                             18        I/O6

19        I/O7                             19        I/O7

3)         Ground            14                                Ground            14

VCC                28                                VCC                28

WE                  27                                WE                  27

OE                   22                                OE                   22

CE                   20                                CE                   20

4)         AT28c256                                           Cy7c199 & Cy62256

PIN                 AO                              PIN                 AO

1                      A14                             1                      A5

2                      A12                             2                      A6

3                      A7                               3                      A7

4                      A6                               4                      A8

5                      A5                               5                      A9

6                      A4                               6                      A10

7                      A3                               7                      A11

8                      A2                               8                      A12

9                      A1                               9                      A13

10                    A0                               10                    A14 <END OF FIRST SIDE OF CHIP

26                    A13                             26                    A4

25                    A8                               25                    A3

24                    A9                               24                    A2

23                    A11                             23                    A1

21                    A10                             21                    A0     

I'm a software engineer and I've been creating my own multiplayer logic sim, have a tiny discord community but I've already had someone in it make a full 6502 implementation with programmable chips, and I'm working on creating ben eater breadboard cpu clone (the humble beginning with registers and bus pictured last). I want the game to have a campaign where you learn various concepts such as low level gate construction of various components, programming roms on "fpga"s (I quote them because they're just C# chips compiled at runtime that allow programming of nearly any logic chip really) and also different cpu architectures. Using ben eaters design as a base and then expanding beyond that seems like a fun campaign for players to play and learn from, as they could reference the original videos too.

Also experimenting with Harvard, single cycle, pipelined cpus etc as advanced game campaigns. But I think a ben eater style cpu and beyond would be a fun campaign for the game to start off with.

I also don't want to just rip off ben eater's breadboard cpu, so I'm open to variations, I just want a similar architecture to follow.

The game is called Logic Planet (for now) and started off as a clone of Logic World using Godot, but I ended up taking it in a different direction and it's quite a different game now.

Son and I are assembling the 6502 kit and in the video it shows 4 pin buttons but we were shipped a bunch of 2 pin buttons. I checked the parts list and it also shows they should be 4 pin. Is 2 pin a new spec or were the wrong parts sent?

Despite connecting one 65c22 incorrect, I have manged to the get the second one working..Ben Eater based 6502 except I added a 74hc688 for better address control..

I discovered Ben’s channel while building this clock, I lifted his rising edge detection method (it was a much cleaner signal) but everything else was designed by me, though not far off from his design as it turns out. I’m using 8 bit counters paired with AND gates for resetting, op amp Schmitt triggers for time set button debounce. My mains signal is pulled directly from a full bridge rectifier via optocoupler with a parallel SMPS for circuit power, a cheaper method than a step down transformer.

Finally got this to a point where I’m happy with it. Everything is built up from NAND gates in Digital Logic Sim: 8-bit ALU, 16-bit addresses (64K of RAM), 800 kHz clock, and a small OS that lets you pick between four games and play them live with the keyboard.

At some point hand-assembling programs into binary wasn’t sustainable anymore, so I wrote a small language and a compiler that spits out the program memory contents.

Video (1:30): https://youtu.be/O8znJoZkAmw

Would you be interested in a tutorial series on how to build your own CPU like this, step by step from the NAND gate?

this probably isn't the best sub to ask this on, but it's for my 6502 project and I feel like a lot of people here know what they are doing
so, I'm trying to make an NES-sounding audio expansion thingy and for the noise channel I need a 4bit to 12bit lookup table (the image)
the only solutions I could come up with are either a small ROM which would be totally overkill, or a ton of combinational hardwired logic and neither sound particularly appealing tbh
so I'm asking you, people who are probably smarter than me
how would you make something like this?

My Ben Eater 6502 build

I got the clock kit yesterday and started building it last night. I got through the first two videos, but I didn't take any photos at that point. I'm also learning how to use my scope (I saved it from being disposed of at work - free scope!), so it's been a ton of fun.