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@ Grapeshot Thank you very much for weighing in here. You cleared up much of my confusion. I did see that FT 4.0 was loading to $A64A but did not know it was causing the issue.
Thank you for the vegaplay patch, very cool of you.
Yogi

All the mappers with expansion audio require initializing their banking registers, while a plain 2A03 song won't. (Well, won't unless it's too large for an unbanked NSF) What is causing me the most confusion is the fact that the grapeshot VRC7 NES plays. I think this is Grapeshot's youtube vid http...

How big is the resulting .nes file? Not sure how the emu will handle files smaller than 32KB. You'll want to ensure that all code ends up in the fixed bank of prg rom $E000-FFFF (8KB). If it's already 32KB, but required data is outside of $E000-FFFF the emu probably isn't starting up with the banks...

Hi All, I'm trying to find a way to build an .NES from a FT VRC7.NSF. I've run across a hack to Vegaplay by Grapeshot but I need some advice. http://forums.nesdev.com/viewtopic.php?f=3&t=9102&p=96897#p96897 I have a simple test FT 0.4.3 song that uses VRC7 and 2A03, no bank switching, less t...

I went back through my notes in regards to the mentioned odd readings. The test procedure for each Xtal group was to insert the Resistor then run through the different Capacitors, taking the readings. For the 14.970MHz Xtal group I broke this pattern; starting with 68pf and then realizing that I had...

Thanks for taking the time to explore this! Naïve question: any idea why the free running frequencies not independent of the value of the missing crystal? The really visible outlier is no xtal/14.96MHz/10MΩ/220pF. Are you asking in regards to the vast difference between the RC TC Res Frequency and ...

Last day and a half I've been testing the HCT74 osc. I've compiled a data set of the tests to try to understand the circuit better. Keep in mind that my test circuit is on solderless breadboard which has a lot of stray C and my DMM only has a range to 4MHz with 4 digit precision. In order to test in...

I can only tell you what my experience has been with a Willem. I have burned EPROMs from 2732-27C010, for the most part without too many issues. I use USB to power it and that seem fine even with EPROMs. I've needed to re-position the chip in the ZIF to get a good connection a few times, but could h...

Weird. The original frequency was already just 7kHz, I'm surprised dropping it to 40Hz helped things (as opposed to, say, simply reducing the strength of the bias resistor). Or maybe the extra capacitive load did something. That large of a capacitance should definitely drop the effective frequency ...

Interested in your design :) Very clever. I'm not the best one to offer advice but I'll throw my opinion out here anyway: With #1 you would have to depend on how each game handles WRAM, this could limit you to what title will run on this hardware. #2 could be useful for a menu system that retains us...

The only way I can couple to the /2 FF is by running the /Q output through a HCT14 inverter gate. […] If I directly couple the output to the CP input of the /2 stage, as per the patent doc, I see the 2MHz signal at its outputs with no division. Inputting a higher drive level signal (my 3.58MHz HCT1...

google provides this link from the image in the patent: http://patentimages.storage.googleapis.com/pages/US4980655-1.png The patent looks like it expired in 2003 due to failure to pay maintenance fees. It should have expired in 2007 regardless. Well good news and bad news. First: I'm using HCT74s, ...

YM3812: readily available oscillator, needs external DAC YM3014 or similar (costs more than synth), no mixing needed. Hm. The complexity of translating the bitstream to ordinary I²S is definitely within the range of the least CPLD, if not just a microcontroller. And the cheapest I²S DAC I can find ...

google provides this link from the image in the patent: http://patentimages.storage.googleapis.com/pages/US4980655-1.png The patent looks like it expired in 2003 due to failure to pay maintenance fees. It should have expired in 2007 regardless. The 74HC74 datasheet indicates two separate inverters ...

You can get 15.36MHz xtals pretty easily, and apparently US patent #4980655 (long expired) details a method for using a 74HC74 to both drive a crystal and divide its output by 2. That gets you to within 2 cents of correct, too. And it looks like the 74HC74 shouldn't have any problems at those frequ...