Unknown VDP: Yamaha YM2220

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By lintweaker

Master (148)

lintweaker's picture

30-04-2019, 17:29

This site gives a nice list of Yamaha ICs. Unfortunately the YM2220 is not listed
List of Yamaha ICs

By Piter Punk

Master (201)

Piter Punk's picture

30-04-2019, 22:51

gdx wrote:

A little more complete pinout description of 315-5066/YM2217 pinouts (SG-1000 II) :
http://www.smspower.org/forums/13455-Sega3155066PinoutsCustomChipInSG1000II

This is the post that I used to make the pinout diagram. An attention point is that, like the pinout that I did for YM2220, it was created following the circuit trails in the PCB. So, the unconnected or unsilked pins can't be identified.

gdx wrote:

I found several info about 315-5124/YM2602B:
http://www43.tok2.com/home/cmpslv/Mark3/EnrM3.htm
At the bottom of the page, there is a test program of register #3 pf VDP. I convert it to MSX. Can you try on your Victor HC-30 and Casio PV-7 with a joystick (By using buttons A & B)? This program does not seem to work on a MSX's VDP.

Ok, can you send the converted program to me?

Thanks!

By gdx

Prophet (2707)

gdx's picture

30-04-2019, 23:23

By Grauw

Enlighted (8015)

Grauw's picture

09-05-2019, 22:52

Grauw wrote:

Here is my test program. Execute in DOS in screen 0.

	org 100H

Main:
	ld hl,helloWorld
	ld a,0
	out (99h),a
	ld a,64
	out (99h),a
	ld c,98h
	ld b,12
	ld a,b
Loop:
	dec a
	out (99h),a
	outi
	jr nz,Loop
	ret

helloWorld:
	db "!dlroW olleH"

In openMSX TMS9918 (Yamaha CX5M), this prints “Hello World!” at location (0, 0).
In openMSX V9938 (Philips NMS 8245), this prints “!dlroW olleH” at location (0, 0).
In openMSX V9958 (Panasonic FS-A1GT), this prints “!dlroW olleH” at location (0, 0).

On a real TMS9929A (Sony HB-75P), this prints “Hello World!” at location (0, 0).
On a real V9938 (Yamaha CX5MII), this prints “!dlroW olleH” at location (0, 0).
On a real V9958 (Panasonic FS-A1GT), this prints “!dlroW olleH” at location (0, 0).

Executable binary here

What does this do on the YM2220? The Sega VDP behaves like the TMS9918. This should give some further insight whether the YM2220 logic is similar to the TMS9918 / Sega VDP or the V9938 / V9958.

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