retrocanada76

FGPA is not like any other computer language. You need to understand that it runs in parallel and how the signals interact each other, that's the most difficult part to grasp. It's an electronic description language not a computer programming one.

no this is old code. The ram is taken form the integrated SDRAM and is 128Kb. I don't know if the eseMSX VDP has support for the extra 64K bank. Anyway for an MSX is useless I never seen anything that uses it as the access is not trivial.

the 9958 uses the ese-msx3 FPGA code. Has nothing to do with f18a. the 9958 has no Light Pen or Mouse support, they don't seem to have been used on MSX2 anyway.

ah ok this computer uses 9938 instead of 9918. Right you don't need the A1 it is already in the socket. BUT, I never tried a 9938 computer there are few pin differences. I tried on a 9958 OMEGA MSX using the 9958 jumper.

get this pin 80 (A1) and connect it to the MODE1 i showed you. Don't bypass anything the pin is there to be easily connected / disconnected.\

the signal goes further down to tang where is serves as MODE1 together MODE0 they make the 4 registers

You need to connect MODE1 (from the socket) to A1

it's called MODE1 because it goes to MODE1 on the 9958 but it is in reality the A1 line.

i'm talking about the small board that you plug into the TMS socket. Just look at it.

The tang20k socket (which is the same for tang9k 9958) has a A1 pin on it. You need to pull a jumper for the address bus A1 because the 9958 has 4 register ports (on MSX2+ they are x98, x99, x9a, x9b)

But you really need A1 line to be connected or you may write garbage to it. You need to pull this line somewhere else in the computer as the TMS socket does not get it

I have no idea how a normal boot would be I don't know this kind of computer but for the tang to display something means it has set R1 BL field to 1. So it initialized it. Now it might be partially initializing it and this is the reason you are seeing garbage. I don't know what are the default values for a real TMS9918 for the R0-R7 registers. These are set in the vdp_register.vhd module. You can look at the default values then RESET line is active

ok, It seems to be working. Did you connect the A1 line ?

I don't have a master system.

what do you mean by standalone ? A full SMS loading from the SD ? I'm not thinking on that.

Well that would require to stretch the image there is no magic, the resolution for the V1 is 640x480. But there is no frame buffer the image is generated on the fly so with limited memory from the TN9K this is not possible.

Well you can set it to 9938 (it will disable the 9958 features) but the light pen/mouse and color bus features are not implemented. They are analog inputs/outputs these things don't work as simple on FPGA.

@Duewester what do you mean electrical drawings ? It's all there in the KiCad project file. Open the pro file and select schematics. For people having a bad time with specific monitors I suggest you give a shot to this thingamagik: https://www.amazon.ca/axGear-Repeater-Booster-Extender-Amplifier/dp/B07DFWW8NC/ref=sr_1_9?crid=1I5XAAB3CYX0X&keywords=hdmi+booster&qid=1695261091&sprefix=hdmi+booste%2Caps%2C148&sr=8-9 It costs 8 dollars and what it does it re-converts the HDMI signal to a more reliant one. You will need an intermediate hdmi cable so get a short one. It does not require power it gets it from the hdmi. Neat gadget.

Great, then try a simple hack: add a 102 cap between GND and the ADC input pin 2(put under the board it's easier) it will filter a lot of hiss. You can try other values.

@Duewester i am trying this and i am getting a good audio.

it should be V2 9958. The V3 is for the Tang 20K. I will test some audio improvements the people from MSX makers are helping me out.

@Duewester Did you get my latest core ? I improved the sound and fixed the screen tearing. Try adding a 0.1uf or 0.01uf ceramic cap in series with audio and the connector. See if we can filter anything. On my MSX the sound is pretty decent now. Try also the V2 9958 just for the fun of it. I fixed it too.

You can just run the versions v2_9918 without the VGA breaker, It should work without any audio just like the v1. The vga output is not good either so i am not changing it there is no point.

the audio seems to have improved substantially. I changed the inputs from pullups to pulldown. at least on MSX que quality is visible, I mean, audible both v2 version have been fixed