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Merry Christmas CJ! (Greg)

man I have to build my ben eater style 6502 which is still pending on the register/bus design

cool hat the same pproblem wuth my project 65816

Fascinating, thanks for this.

I'm so glad TH-cam recommended this video to me! I've been trying to get cc65 configured to work on my own 6502 sbc for a while now with very little success.

Loved this project! Please, keep it going.

Promo-SM

I was thinking Dr Who

❤ great stuff CJ! Brings me back to ISU days

If you have opamps... why not use an active filter (e.g Sallen key) intead of just buffering two chained passive filters? Additionally, a shift register and a R-2R resistor ladder can easily produce a stable voltage and act as a single 8-bit DAC. In your case, if you have free GPIOs, just use 6 of them with an R-2R ladder to get 64 different output voltages.

Nice work. I like moritz' videos. I built the vco and then went down a rabbit hole trying to tune it. I built a programmable CV controller with an Arduino which made the process a bit less painful. Keep it up!

💋 'PromoSM'

Could you eliminate the 'OR' gate IC by connecting the /WE signal to one of the active-lo gate inputs on the Expansion Board '138 decoder IC or would that introduce additional propagation delay?

Very nice and educational blog & video! Thanks. You have "a fresh" approach to use OS'es gfx routines for the classic amiga vector effects. Not very many were able to achieve that back in the day. There was some AGA vector intro coming out somewhere in 92-93 (the sailing boat thing, whose was it?), which used fancy KS3.0 double buffering routines on an Intuition screen. I wonder how your demo runs on AGA or RTG machines? Copper effects surely get disabled when on RTG... (OH! And I totally agree on Mistake #3: "Wait until the last minute to test on real hardware" Been there done that. A few times actually ;)

Nice work!

Merry Christmas. Great work!

Merry Christmas!

Super impressive! Go rebels!

Very cool! Very Impressive!! Happy Holidays!!

Nice, and impressive the system still works after 10 years! It sounds a bit like an audio system i made a few years ago, which had two channels of square waves driven by 40103 down counters toggling D flipflops. The software configured the reset values for the counters, with one being an octave divider and the other choosing the note. So there were four counters overall, and a D flipflop pair, for two channels, and I had to "trill" in software to get more notes in chords.

Love it!

Very cool. Nice demo.

Are you directly driving those LEDs? The current (per userport output) should not exceed 1mA, therefore you should use some sort of driver (transistor, ..). Otherwise you risk blowing up your poor CIA chip.

Thank you!

Awesome!

For everyone saying the C64 doesn't have hardware scrolling, it has $D016 to scroll 7 pixels which is hardware scrolling compared to for example the Amstrad CPC. Scrolling the whole screen can be done by scrolling 7 pixels first and then copy the screen contents 1 char to the left of right depending on which direction you scroll. This takes a lot of raster time. You can also use a trick called VSP where you don't have to copy all the screen contents but only draw the column which is at position 40 hidden behind the border.

Nice work!

Very nice. What language did you do this in and is the code available?

This is from 2015 and I'm from 2020, but this can go faster. The key thing to make this fast is to "XOR" the output of the blitter in line-drawing mode, by color, on all their respective bitplanes. When that is done, you copy from your XOR'ed wireframe bitplanes straight onto the destination in fill-blit mode. The effect this has is the transition from the background (0 color) to the edge (eg. green) will just be a green line, but the edge from, say, green to red, will have only those bits set that are different; consequently, the blitter, in fill mode, can fill all polygons in one operation. You will *easily* hit 50 fps this way. It is for this reason that convex shapes are a lot easier to do on the Amiga than concave shapes (eg. Scoopex Mental Hangover, to name a demo, the shapes with holes are a lot slower than cubes and whatnot.) I noticed on your blog that you're using the OS route (AreaMove()/AreaDraw() and whatnot, which is cool, but to go fast with the above technique, you have to hit the hardware. Hope this comment is enjoyable for whoever reads this and wonders why there is a speed difference between this and the demos. Great job, I enjoy your work, thanks!

Just a note: with a total use of unrolled code (both characters and colours) and dealing with racing beam in the correct way it's even possible to do smooth scroll without using double buffering. The bad news obviously is the big waste of RAM and the fact you can use only half or less of the available cycles for the last frame and the next one, when doing the copy. This technique was sometimes used early in the day (international soccer for example)

Very cool! Nice demonstration of stiff equation and its consequences.

Hello I would like to control 2 outputs via 2 5Volts input signals. Can you help me?

Love this!!!!!!!

Does anyone have a copy of the source code mentioned above? The link above doesn't have a valid URL anymore at the end of the article :( The Wayback machine isn't working for it either...

Great ...thanks

Can 6502 rom and memory be used on the W65C02 (are they interchangeable), and also is the assembly language the same or simila

It's a common misunderstanding that the C64 has hardware scrolling, it doesn't. What the C64 has is just hardware pixel offset achieved via a pair of 8 bit registers to control the vertical or horizontal pixel offset for the screen between zero and seven pixels :o)

That is no _hack_ ! That is the classic method for scrolling on the C64. The C64's hardware scrolls only 8 pixels. Sega 8-bit and NES do the entire scrolling in hardware, wrapping around at the borders so programs need only replace blocks in a line (or two) just outside the border. Doing that horizontally is _almost_ possible on the C64 with a hack though: th-cam.com/video/ZsRRCnque2E/w-d-xo.htmlm46s You would need to swap to a new buffer only every 320 pixels.

I don’t understand why you need two play fields for this? There is nothing here that would require the need for two play fields if you are aiming for this simple single color graphics. Or are they just placeholders?

I ran into something odd trying this experiment out(I'm using the second edition but that doesn't matter). For some reason the bistable 555 wasn't able to latch on stopping the displays. I made a bistable 555 timer on a separate breadboard and it worked fine, It's output turned on an led and stayed on. I made another bistable 555 timer below the first. When the first 555 is turned on it powers the led but when I turn the second 555 timer on it powers It's led but turns off the first timer. So at the moment a second astable or bistable timer will consistently turn off any bistable 555 in the circuit. They have only shared - and + busbars and Outputs go to leds. What is making this happen? Really confused... how can they effect each other without direct connections to input, reset or control pins?...

Hey Chrsitopher, it works on both directions? Can you read TTL data?

Nice, but I don't seed the code at the link

Hi im new to digital electronics and i want to know how to program a eprom and how to wire this upp but cool project!

try a dac0832 chip x 3 for red green blue pins on a monitor

I'm trying to place your accent it sounds like Irish via England and the USA.

I want to build a VERY basic 6502 PC, that can be programmed like the altair 8800. What do i need for that? Would the CPU and the RAM be enough?

I am a bit confused, could you not have used a 555 timer just to flash an LED, would it not have saved you a lot of bother and trouble to used a Microprocessor and an Eprom and a 4Mhz clock oscillator to do this, and how you then have to write a software and assemble it and load it into eeprom to run that LED flashing loop, another byte that confused me is you said that you have wired the LED to one of the address lines, and also said you have not yet programmed any I/O lines, so how can you claim that the LED is flashing due to a software aspect, I thought any address bus is used for calling up locations in a memory cell or cells, and then you need other instructions to enable output and extract data stored in that location, and or write bits or bytes at that location, and only then you can truly demonstrate what you can then do with those bits and bytes to do a thing like flashing. i may be wrong and still a big fan of 555! ( Please feel no offence - one is not intended at you) PS, as I was typing above, my wife was also reading what i was typing, so she said to me " Don't be daft all your life, he is not trying to flash an LED, but demonstrating the ability of a microprocessor and software capabilities, I hope she is wrong or else I am in big big trouble, she has time and again warned me if I don't act my age, she will definitely divorce me, she thinks I am really daft! Hey that was a joke, but well done to demonstrate how to start acquiring skills in using a basic processor and writing software, for dafties like me. thanks, keep up the good work, but sadly i am still stuck with CMOS and %%% timers and would like to lay my hands at these sexy processors, my wife is a real bitch.

learn the loops . store program lines with the enter key. dont be an isolate-- 1 individual. hook to a monitor. take billions from old bill gates. line up decimals.

Very nice. Actually I can't recall A500 demo with such transparent vectors on moving background.

wow...... thats really really deep... only way to communicate is an led lighting up and turning off.....