TMS9918A on Arduino

Use a chip from 1983 to show fifteen different colors on a TV screen, with a Mega2560 and a breadboard.

[adamwishneusky]

Awesome! Thanks for reminding me I have some lentils in the cabinet I’ve been meaning to cook 😉🤓

[cbmeeks]

This is AWESOME! You've inspired me to dig out my TMS chips and get building. I built a 65C02 SBC a couple years ago and this would be a perfect fit.
Please post more!

[petertayler]

Very highly quality content. Thank you. I've been looking to follow another Ben Eater. Happy I found your video.

[GeorgeFoot]

Very nice! It looks like a handy IC, especially with the sprite layers too!

[derekchristenson]

Very interesting! I'll have to check out your subsequent videos on this topic.

[stevelitt]

I’ve been looking for an easy way to add a display to my Ben Eater kit 6502 computer and I found this super helpful and informative. Thanks so much for sharing.

[colonelbarker]

Thanks for making the video! Greatly enjoyed.

[janikarkkainen]

Very nice to follow along your procedure. Almost Ben Eater -esque presentation, love it!

[chenzhuoyu]

9:16 It's an emitter follower circuit, to drive the 75Ω coaxial cabel (and impedance matching), that's why R1 is 75Ω.

[jblangston]

Nice video! I see that you noticed the voltage is a little too high on the output. This can be adjusted by putting in a ~130 ohm resistor in place of R2 which is specified in the schematic as 0 ohm (aka, a wire). I talked to Michael about including the extra resistor in the kits but I'm not sure if he has yet. The circuit I used for my board originally came from a document by Tom Lemense, and like you I'm not too good at analog electronics so I just blindly copied the output stage from his schematic. However, later I measured the voltages and realized they are high. Having a higher voltage doesn't hurt the TV as you found out, but it does make the picture brighter than it should be. This can be compensated with the TV's brightness setting but then if you switch the input to something else, it will be too dark. I experimented and found that 130 ohm yielded a signal pretty close to the correct voltage, but anything in that approximate range would work if you don't have 130 ohm on hand. The colors would just be a little brighter or darker based on the value you used.

[garymetheringham]

hi, I've been trying to get my tms9918 to work with the arduino, tv connects saying ntsc input signal but all oi get is black and white vertical lines that change pitch as colour changes from arduino. any ideas?

[sarvadnyadesai]

Nice work👍deserves more subscribers...

[Nebula_Protogen]

Is there any way to do this with an Arduino Uno instead of an Arduino Mega?

[codeskknows]

Hi there! I am currently working on designing a computer with the TMS9918ANL where you able to get it to write to VRAM? I am currently trying to get it to work with AVR so when the interrupt pin goes low it will try to write to it.

[artursmihelsons]

Nice! 👍
For first run, I will, definitely, wire up video RAM.. That will display garage on screen to verify, that video chip is actually working..
Probably, I'm old school, but assembler better fits in to my brain logic.. 😂 That's why I don't use Arduino, but program Atmel chips directly..

[microhobbyist]

I see you set up a PS2 keyboard. I'm implementing one at the moment. It's interrupt-driven through the clock. I also made a polled version. All is working fine, but have you tried using other interrupts, like a continuous timer? This really screws things up and messes up the keyboard packet framing. I'd love to see a video on your implementation of the PS2 keyboard, as well as dealing with other interrupt sources. I'm not a pro, just a hobbyist, so, I'm obviously missing something.

Early on in the video, we see you are using BASIC. Which version of BASIC are you using? And where can I find it?

[vanhetgoor]

Why 32 kB of RAM on a chip that can only manage 16 kB of RAM?

[manhattanmoments]

I love it! Very nice done! Just to be sure, it’s an NTSC signal coming out, correct? ... and PAL wouldn’t work with that

[deltakid]

Please, more about this using Arduino!!! Please!!!