Amiga HDMI with a Raspberry Pi! (RGBtoHDMI)

hi it's jan beta and i have my amiga 500 set  up here running monkey island as you can see   and currently i have it hooked up through the  original rgb output running to my ossc upscaler   that converts the signal to an hdmi signal  which can then be displayed by my modern   modern(-ish) monitor here and it looks rather  good picture quality is amazing there is however   a downside to this because upscalers like the ossc  are rather costly and the inexpensive models like   the flylink upscaler that i have also set  up that i made a video about a while back   are not quite up to the task they often suffer  from input lag and are rather unusable or   only usable to an extent when it comes to playing  fast paced games and such so they are not really   a good solution the ossc is brilliant and i can  definitely recommend it for everything it supports   rgb and component and vga to an extent and it's  been a good purchase so i can recommend the oss   however it costs a lot of money and there is  a new solution specifically for the amigas   and for some other systems that comes in the  form of this little circuit board in combination   with the humble raspberry pi zero which of course  as you probably know is like a little single board   computer based around an arm processor that can  run software from a micro sd card and it has   an hdmi mini output and there is a new software  or relatively new software that's called rgb to   hdmi made by hoglet67 and that allows this little  device to convert rgb inputs coming through these   gpio pins here to convert that to an hdmi output  that can then be displayed on a modern monitor it   is a bare metal software so it just boots from the  microsd and runs without any operating system so   it's self-contained software which makes it really  fast and it's directly communicating with the   processor and the graphics output circuitry that's  in here to have very little lag this project was   originally aimed at the bbc micro of all things  but can of course be adapted to a number of   different systems that all have different  kinds of rgb outputs and that's where this   comes into play this little adapter board was made  by c0pperdragon who also did the component out mod   for the commodore 64 that i made a video about  a while back this basically sits in the denise   socket in the amiga which is the graphics chip  as you probably know and then you put the denise   in here and the raspberry pi on this socket and  then the denise signals are converted to hdmi out   which of course is a rather inexpensive and  versatile solution to get hdmi out of your   amiga so this little board has two 74lvc574s on  it which are octal d-type flip-flop chips and this   smaller chip is a 74lvc86 which is an exclusive  or gate and this little package is just a voltage   regulator that regulates the 5 volts that it gets  from the chip socket to the 3.3 volts that these   modern chips need as an input voltage and it's  just taking the rgb signals from the denise   converting them to a format that the  raspberry pi can understand and putting them   into the gpio pins of the raspberry pi and then  the magic is happening in the bare metal software   on the raspberry pi and the raspberry pi  should output an hdmi signal through the little   mini hdmi port at the moment this version works  with the old style denise chips so not the super   denise there is a version two of this already  that can handle the inputs from the denise too   but it doesn't support the new video modes  that the enhanced chipset outputs so for now   this should be perfectly suitable for an amiga 500  for example that has the 48-pin old-school denise   and not the super denise for the later models  it is perfectly possible to make an adapter for   those i think uh because the denise has  the same outputs but it comes in a plcc   package so it's not so easy to build a socket for  that so the plan for today is to put this into my   original amiga 500 and install the software  on the sd card in the raspberry pi and see   what we get this should technically  be a pixel perfect representation   of the amiga output and it should have  very low lag and very low latency so   yeah let's see where we get with this the software  as well as the hardware side of this project are   open source so you can download the rgb to hdmi  software that you put on the little sd card   and you can also download the gerber files to  make this adapter board from c0pperdragon's   website and from hoglet's website respectively if  you plan to have your own circuit boards produced   for this little project i can recommend the  sponsor for this video pcbway because they are   my favorite prototype pcb manufacturer they also  do larger scale projects but they are perfect for   little small scale projects like these and  deliver excellent quality have great service   and very reasonable pricing so check them out the  links are in the video description let's try this   so i'm on c0pperdragon's github page now where  he explains a bit more about the amiga version   of the rgb to hdmi adapter and he also has a  direct link to the software which also has the   bootloader for the raspberry pi which we need  some of the releases listed on the rgb to hdmi   github don't have the bootloader which of  course won't boot our raspberry pi we need that   to run the bare metal software on there so  this is probably the latest version it's from   november 2020 which has the bootloader on  there and i'm going to copy this to our sd card of course this comes as a zip file you need the  bootcode.bin here and we are going to copy this   all of these into the root directory on our  cart and then we should be ready to go on the   raspberry pi side of things and we have to take a  look at the amiga and how we install the hardware   so i'm now just putting the  sd card into the raspberry pi and this should now be able to boot  the bare metal software for rgb to hdmi   okay let's open up the amiga been a while since i've been in here as i said  this is my original amiga from back in the day   that i restored for one of my christmas specials oh and it has the shielding in of course so  we're going to have to remove some more screws bending some tabs i think it should know come out yeah here's the insides of my beautiful 1987 amiga  500 my original one and there's our denise chip   which we are going to put our adapter board on  hopefully it fits we're going to see i'm going   to remove this chip put in the adapter socket  put in the chip and put the raspberry pi on top   there we go so the little notch should be  facing this way the chip goes back on top   okay so the pie actually plugs in like so and  now we should plug in our mini hdmi cable like so and that should be it um the newer versions of  these adapters actually have a jumper on the   bottom side where you can set the denise you need  but this is a version one which only supports   these old style denise chips so just make  sure you set that according to the version   of the denise you have usually in these  old ocs machines you have the ocs denise   and in the newer for example the amiga 500 plus  and some amiga 2000s you have an ecs super denise   so this should be powering the adapter and the  denise and the pi zero through the original socket   hope this works so yeah have everything hooked  up let's see if we get a picture output and if   the raspberry pi starts up oh look at that  we get a nice rainbow colored output there okay there we go and it actually works beautifully   we get this startup screen that's the moment the  software starts up and then we get a crystal clear   picture from this that looks crisp that looks  way better than the ossc output which is already   really crisp so that's really impressive let's  try something a bit more demanding on the hardware   and i think that actually started up quicker now  probably it wrote the code to it which setting   it's supposed to use i'm just trying the regular  turrican test that i do every time basically okay and this looks it is absolutely  stunningly sharp it's really good wow yeah this is stunning this looks  like an actual digital output which it is okay let's see about lag and things like that uh this should work with pal and ntsc amigas and for the ecs version only the ecs  resolutions don't quite work yet but   i guess there's going to be  workarounds for that pretty soon   and apart from that who uses the ecs  resolutions anyway i have rarely ever used them yeah it is it is impressive i don't feel any lag wow yeah c0pperdragon says on his website  that it's a couple of milliseconds at most   in terms of lag and it certainly feels like  that really feels like playing this on a crt and i know this game pretty much  inside out i played this a lot   and i recently played it and keep replaying it  keep coming back to it so it feels really accurate that is nothing short of impressive wow okay and that's an interlaced picture and  it's absolutely flicker-free and is displayed   beautifully so that works too the different  resolutions of the ocs chipset supposedly all work and this looks better than through a regular  upscaler because the regular upscalers usually   have this interlaced so it's flickering and the  scrolling is buttery smooth of course obviously yeah this is awesome as this is outputting a 50 hertz signal some  monitors might not quite work with it unless you   have an ntsc amiga which of course then outputs  a 60hz signal but my monitor plays along nicely   which is good i get some slight flashing  lines there from time to time don't know   why that is probably because i hooked it up  through uh the hdmi input of my upscaler here   we're going to see how this looks through my  capturing card in a second yeah unfortunately   we have a slight issue here my capture card  doesn't seem to play too well with the output   from our raspberry pi here yeah the green on the  yet that you can see on screen is supposed to be   black really so yeah it's not quite working  correctly it still outputs the picture fine   and the pixels are really crisp but the colors  are off this is what we get not very convincing yeah it still looks pretty  smooth but the colors are off and we have still we we  virtually have no lag at all the thing might be that it's a 50 hertz output and  maybe my capture card doesn't play well with that but other than that it works really well and  you can see that the pixels are absolutely   uh crisp and sharp yeah it does still work  without any issues with the other setup   just hooking it up to this monitor so i suppose  it's some uh problem that my capturing card has   with the output from this i tried to fiddle  around with the settings and things like that but   i couldn't get it to output a reasonably colored  picture unfortunately still this works as an   upscaler for this one other thing i want to try  the little adapter board actually has a pin header   to connect a tactile switch to switch between  different screen modes and such in the software   i'm going to try to attach the little button  to it maybe we can get something out of the   capturing card or rather into the capturing card  with a different setting in the software there   yeah let's try that let's make a little  cable and connect a little button to it so i made a little uh switch button for   this pin header that is on the board  and it's probably not strictly necessary   to use because the software sets the screen  resolution and such according to what the hdmi   tells it but yeah maybe it's worth having a  look at and maybe we can get my capturing card   to work with this a bit nicer i left this  so long so i'm going to be able to put it   outside of the case in case i want to leave this  in an amiga or just mount it on the case somewhere   and yeah of course you can also buy cables that  have an hdmi socket on one end that you can mount   someplace on the case just leaving  this option open with these long cables you can actually force this to 60 hertz mode by  holding the button down on startup or by just   putting a little jumper there on the contacts  let's try that see if it actually starts up   in 60hz yes and with 60 hertz on a  pal machine you are going to get some   tearing and some uh not so smooth output because  the output from the amiga of course is 50 hertz so   yeah that's going to be not so  great okay so this booting up fine   we should be able to enter the menu by holding  the button for a while ah there we go main menu   okay wow and you can set a lot of options here  palette preferences setting geometry sampling ah   if i hold down the button for a longer time i'm  able to enter the menus i can put it in scanline   mode and all kinds of things that's pretty nifty  but i'm not a huge fan of simulated scan lines   and such so we could probably work around our  issue with the capturing card in the palette menu   but i don't think i want to go into that  trouble we don't have a cpld that's the   menu update for the cpld you can probably update  the cpld code if you use a standalone upscaler   for another system the amiga version doesn't need  this and it's set to auto set the resolution yeah   scaling this auto profile set to omega this is  uh really impressive for what it is it's just   the raspberry pi and this little board that i've  shown you with the little 74 logic chips on there   so there's not a lot to it in this configuration  and you can save the configuration of course   and do all kinds of things auto calibrate we  can test the monitor for 50 hertz support what   i want to do is to test my uh capturing card  with the 60 hertz forced output by pushing   the button during power up i think that  might be a solution for our problem there   yeah and in other configurations this can have  many more buttons and i think also you can hook up   a little oled display to it and things like that i  haven't looked into that at all but you can check   it out on the website and i'm definitely  going to check out more options for this   rgb to hdmi thing it seems to be very versatile  and very cost effective because it's just using   a raspberry pi and a cpld so that's going to  be a lot less expensive than off-the-shelf   solutions like the ossc and things like that and  maybe even more versatile yeah unfortunately we   get the exact same color mismatch even if i put  this in a forced 60 hertz output mode so i guess   you would have to fiddle with the palette options  there to get this to work right in this setup   i'm not sure if i said thank you to c0pperdragon  reinhardt who sent this to me for free for   um checking it out and there is going to be  updates for this this is a relatively new device   both the rgb to hdmi project itself and  c0pperdragon's adapter are still in development   and i guess there's going to be more incarnations  of this you can buy the little adapter board   from c0pperdragon pre-assembled even if you ask  politely and other than that you can make your own   circuit boards and also your own circuit boards  for the rgb to hdmi project which is something i   am going to do eventually and i am going  to check it out for more use cases and more   consoles and computers seems to support a lot of  input signals and yeah the quality is just amazing   yeah that's it for this video thanks for  watching thanks to everybody who supports my   work through patreon or a channel membership  or little donations very much appreciated   hope to see you again on this channel i'm jan  beta thanks for watching see you next time bye

Channel: Jan Beta

Views: 47,108

Rating: 4.9517889 out of 5

Keywords: Jan Beta

Id: e8brkYFoO9I

Length: 24min 8sec (1448 seconds)

Published: Wed Jan 06 2021