Defender/Robotron/Joust on MiST?

[phoboz]

Hello,
Has anyone tried to port the Defender Arcade core to MiST?
If this is ported, it should be easy to support Robotron, and Joust also.
https://github.com/MiSTer-devel/Arcade-Defender_MiSTer

I am trying, but I cannot figure out what the different Clock rates shall be?
(I cannot check the pll wizard, as the Project is for Cyclone V, and the version of Quartus II used for MiST will give an several errors when trying to load the Project)

Code: Select all

105  pll pll 
106  ( 
107  	.refclk(CLK_50M), //// This one is obvious 50 MHz, for MiST it should be 54 MHz
108  	.rst(0), 
109  	.outclk_0(clk_48), //// 48 MHz?
110  	.outclk_1(clk_sys), //// What is this Clock rate?
111  	.outclk_2(clk_6p),  //// What is this Clock rate, phase shift etc?
112  	.locked(pll_locked) 
113  ); 
114  
 
115  apll apll 
116  ( 
117  	.refclk(CLK_50M), 
118  	.rst(0), 
119  	.outclk_0(clk_1p79), //// Another Clock I cannot determine the rate of, name makes it hard to guess?
120  	.outclk_1(clk_0p89) //// Another Clock I cannot determine the rate of, name makes it hard to guess?
121  ); 

Also the Project seems to use a lot of block ram on the FPGA, however, it should be possible to use SDRAM for the ROM image at least.

[slingshot]

You can check it in pll.v, the comment section. As I see, the clocks are: 48, 24, 6MHz, phase shift is 0. Most of the time phase is 0, except for SDRAM clocks.
apll is 1.791044 and 0.895522 MHz.

If you want to use the SDRAM, probably you can use the inverted 48MHz as a clock for it (e.g. SDRAM_CLK <= ~c0)
For a ROM loading to SDRAM example, I suggest you to take a look at the recently updated Colecovision core, it's simple enough.

[phoboz]

Thank's for the tip.

The core will fit in the FPGA provided that the Program ROM, and the Sound ROM is loaded into SDRAM.

The next problem porting this core is related to that MiST SDRAM address bus has 13-bits, however, the Mister core has 16-bits, and the original core (from Dar) has a 15-bit wide address bus for the on-chip Program ROM memory block (the one that cannot fit in the MiST FPGA)

So I need to find a way to make this work with 13-bit address bus for the MiST.

[phoboz]

Please forgive me for aksing perhaps really basic questions on the MiST SDRAM, but; I want to access 32 KByte of data mapped as below with just 13-bits, how can I achive this?

Code: Select all

-- should reflect content of defender_prog.bin
--
-- 4k 0000-0FFF  cpu_space D000-DFFF defend.1 + defend.4  
-- 4k 1000-1FFF            E000-EFFF defend.2
-- 4k 2000-2FFF            F000-FFFF defend.3
-- 4k 3000-3FFF  page=1    C000-CFFF defend.9 + defend.12 
-- 4k 4000-4FFF  page=2    C000-CFFF defend.8 + defend.11 
-- 4k 5000-5FFF  page=3    C000-CFFF defend.7 + defend.10 
-- 4k 6000-6FFF  page=7    C000-C7FF defend.6 + 2k empty
-- 4k 7000-7FFF            N.A       4k empty

[slingshot]

Thank's for the tip.

The core will fit in the FPGA provided that the Program ROM, and the Sound ROM is loaded into SDRAM.

The next problem porting this core is related to that MiST SDRAM address bus has 13-bits, however, the Mister core has 16-bits, and the original core (from Dar) has a 15-bit wide address bus for the on-chip Program ROM memory block (the one that cannot fit in the MiST FPGA)

So I need to find a way to make this work with 13-bit address bus for the MiST.

The physical address bus of the SDRAM is not the same as addressing the full capacity of it (because it has the necessary width for the row address). You should use the SDRAM controller, which gives you plenty of address space, like the one I used in Colecovision for example (Master of Gizmo and Sorgelig have written more than enough SDRAM controllers):
https://github.com/wsoltys/mist-cores/b ... t/sdram.sv
There addr is 25 bits wide, more than enough.
Just give it a clock of at least 8x the CPU clock, and then it's almost the same as using BRAM.

[squid4]

Did you get anywhere with these ports from Mister? I'd dearly love to play these arcade games, some of my favourites, on the MIST. They're also landscape mode games so will look good on a TV.

[phoboz]

Did you get anywhere with these ports from Mister? I'd dearly love to play these arcade games, some of my favourites, on the MIST. They're also landscape mode games so will look good on a TV.

No unfortunately I didn't have enough time. Hopefully someone else will have the time and motivation to do it, because I would also love to see these on the MiST.

[Gehstock]

https://github.com/Gehstock/Mist_FPGA/t ... e/Defender

[DanyPPC]

Many thanks Gehstock

[squid4]

Nice one Gehstock! Thanks. Probably my favourite arcade game of all time.

Sound is distorted and colours are a bit off on SCART but a brilliant start. Keys could do with being reconfigurable as this game is very key demanding.

[Gehstock]

Have really good Sound here with Defender and Mayday(sometimes Missing on Mayday)

Edit :Colors fixed

[squid4]

Looking good now Gehstock! Sounds must be like that in the original core as some sounds are clean.