beneater

Computer noises

Here's a new video that shows the simplest way to get a computer to make noise—amplifying a square wave. I add a BEEP instruction to MSBASIC that lets you generate a beep at a particular frequenc...

Reverse engineering Microsoft BASIC

I'm reposting this because, for some reason, Patreon didn't charge for it when I posted it the first time. I will try to suppress notifications, but apologies for the noise either way.

I've b...

Reverse engineering Microsoft BASIC

This video is a bit of a continuation from my last video. At the end of the last video, I mentioned wanting to be able to print a string to the LCD using a single BASIC instruction. That required f...

Hacking Microsoft BASIC

New video! In this one, I modify the Microsoft BASIC code that's running on the 6502 computer to add some new instructions. Specifically, I add instructions for printing to and manipulating the LCD...

RS232 flow control

Here’s a video adding flow control to the input buffering from my last video. Unfortunately, I ended up running into a problem that I haven’t been able to figure out yet. As you’ll see in the...

How input buffering works

Here's a new video where I demonstrate the consequences of not buffering input and demonstrate how a circular buffer works. The end result is buffered, interrupt-driven input for the 6502 computer....

MSBASIC for the 6502 computer

In this video, I adapt Microsoft BASIC to run on the 6502! Hopefully it all makes sense—there is a lot going on here! This video today is definitely a draft. At a minimum I intend to put the fina...

A simple BIOS for my breadboard computer

New year? New video! I'm finally getting around to videos about getting MS Basic running on the 6502 computer, and this is the first of what will probably be two parts about porting MS Basic and ge...

Adapting WozMon for the breadboard 6502

Here's a quick-ish followup video on exactly what I changed to get WozMon working on the breadboard 6502. In case you were wondering what I had to change to adapt it for the serial interface, andâ€...

How WozMon works

Well you asked for it. After my last video there was a lot of interest in delving deeper into the Wozmon code and explaining how it works. So here you go! I walk through the code line-by-line expla...

Running Apple 1 software on a breadboard computer

Here I demonstrate Wozmon, the hex monitor software that shipped on the Apple 1 computer running on my breadboard 6502. The video mostly shows what Wozmon is capable of without too much time spent ...

Fixing a hardware bug in software (65C51 UART)

Here's a new video in the 6502 series. It's software for the 6551 UART serial interface. Unfortunately this chip from WDC has a hardware bug that has to be worked around. It's not ideal, but not to...

RS232 interface with the 6551 UART

As promised in the last video, here's a look at the 6551 UART and how to interface it with the rest of the 6502 computer. This video only covers the hardware aspect. Perhaps I rambled a bit too muc...

6502 serial interface

Building on my previous videos on RS232 and charge pumps, in this video, I use the MAX232 chip to build a bidirectional serial interface for the 6502 computer.

I point out the limitations of ...

Let's build a voltage multiplier!

In this video, I explain the operation of a Dickson charge pump, which is a simple and clever way to double (or otherwise multiply) a voltage. Charge pumps like this are typically used in low-power...

Yearly kit sale

Thanks again everyone for your support. I just wanted to let you know that if you've been thinking about buying one of my kits, now is the best time of year to do so. Head over to 2022-11-24 20:04:53 +0000 UTC View Post

Hacking a weird TV censoring device

So, um... I saw this recent video by Technology Connections about a bizarre device from the 90s that attempts to ...

The RS-232 protocol

New video? Yes! It's been a while... But I'm getting back to the 6502 computer with plans to add a serial interface, which will allow for a ROM monitor and ultimately a more functional computer. An...

Black Friday sale

Heads up that I'm running a 10%-off sale on all kits starting today at 2021-11-25 22:46:57 +0000 UTC View Post

Why was Facebook down for five hours?

Hey everyone,

I'm still working on some tweaks for the hardware timer video, so I still haven't published that on YouTube yet. But last week, as you may know, Facebook's entire service was of...

How do hardware timers work?

New video! Back to the 6502 computer, this video looks at some of the unexplored functionality of the 6522 versatile interface adapter chip. Specifically, I cover the timers and how a CPU and softw...

SPI: The serial peripheral interface

I've gotten a few requests for videos about different communication protocols, so here's a video about a communication protocol! SPI is one of the simplest IC-to-IC protocols. I explain the protoco...

How does n-key rollover work?

New video! I dissected a keyboard that supports n-key rollover to figure out how it works. It was fun figuring out how to capture the USB signals from this keyboard since it only wanted to talk at ...

How does USB device discovery work?

New video! What happens when you first plug a USB device in? There's a whole lengthy conversation where the computer discovers what a USB device is capable of. In this video I capture the conversat...

How does a USB keyboard work?

This is sort of a continuation of my other videos on keyboards, but really it's more of an exploration of the low level operation of USB. Hope you find it interesting!

As always, let me know ...

4-bit LCD interface

Many of you noticed that for the keyboard videos, I modified the LCD to operate in 4-bit mode, freeing up some IO lines to make the 8-bit keyboard interface possible. I’ve gotten a few messages f...

Keyboard interface software — final video

Here's the final video... finally. Sorry this took longer to get to and finish up than I'd hoped. But thanks to everyone's feedback, I tried to clarify the circular buffer a bit. And I added a whol...

Keyboard interface software

Thanks everyone for the feedback on the last video. I appreciate the thoughts in both directions on splitting up the video. The comments that resonated most with me were that the software part felt...

Building a keyboard interface

EDIT: This is now the final video and it's just the first part (hardware). I'll repost the software section as a separate patron video with the plan of expanding it a bit before releasing it.

So how does a PS/2 keyboard interface work?

New video! Here's a video where I poke around with the signals generated by a PS/2 keyboard and build a very basic—and somewhat impractical—circuit to decode them. I also discuss a few differen...