New FM Enabled Power Base Converter Prototype

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db-electronics
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New FM Enabled Power Base Converter Prototype

Post by db-electronics » Sat Mar 01, 2014 11:34 pm

Here's my first prototype for an FM enabled Power Base Converter.

I had the idea to make this after seeing etim's FM sound expansion module for the SMS - why not have the ability to hear FM sound for a SMS game on Megadrive/Genesis as well?

To sum up the design, here are the major components:
-YM2413 stand-alone IC
-Altera CPLD to handle address decoding (I eventually want to implement stack initialization code in here just like on the official Power Base Converter (VHDL code attached)
-Quad Opamp to amplify the RO and MO outputs of the YM2413 and drive the SL and SR inputs on the Megadrive cartridge port

Check out the FM PBC in action in this video:

http://youtu.be/7OiDo46SAxU

Update 1:

I've succeeded in running mode 1 - essentially mode 1 includes an EXACT copy of the initialization code found on the original and official Power Base Converter. This particular routine sets the Z80 Stack Pointer to $DFFF.

http://www.smspower.org/forums/viewtopic.php?t=14084

This solves a number of bugs for the FM Power Base Converter. Firstly, it enables the game R-Type to load immediately without needing a special trick (see video linked below). Second, it prevents Double Dragon from crashing at the first level as seen in my first post's video. Here is the improved FM Power Base Converter in action:

http://youtu.be/Cqwwmff4zN4
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foobat
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Post by foobat » Sat Mar 08, 2014 11:18 am

Wow, dude, that's awesome

inu
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Post by inu » Sun Mar 09, 2014 12:55 am

Yet another mind blowing project on the Mega Drive\Genesis.
Congratulations!

db-electronics
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Posts: 89
Joined: Mon Feb 24, 2014 6:04 pm
Location: Kapuskasing, Ontario, Canada
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Post by db-electronics » Tue Mar 11, 2014 3:03 pm

I want to try and compare the audio quality between this and a 100% VHDL solution.

I can get the YM2413 chips from eBay but I'm a bit weary of relying on said stock; I'd rather have a soft solution.
What does db stand for? Well that's an excellent question...
http://www.db-electronics.ca

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