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Crazy Idea - MT32 WaveBlaster Card

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Reply 40 of 96, by gdjacobs

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RJDog wrote:
PhilsComputerLab wrote:

If it's ok with you, I can merge with the existing "Munt on Pi" thread and move it to Sound?

Yeah, I followed that thread pretty closely; definitely good work. My attempts here are to essentially productize that idea into a unique form factor. I don't disagree with merging the two... for sure both belong in Sound.

That's my thinking as well. I want to create a synth module capable of mounting in a drive bay or on the desk that can handle all LA synth or sample based synthesis.

All hail the Great Capacitor Brand Finder

Reply 41 of 96, by hard1k

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MuntBlaster?..

New sound card project: AWE64 Legacy
Please have a look at my wishlist (hosted at Amibay)

Reply 46 of 96, by hard1k

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gdjacobs wrote:

LABlaster?

BLABLAster 😁

New sound card project: AWE64 Legacy
Please have a look at my wishlist (hosted at Amibay)

Reply 48 of 96, by brostenen

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M-Daughter-32

Don't eat stuff off a 15 year old never cleaned cpu cooler.
Those cakes make you sick....

My blog: to9xct.blogspot.dk

001100 010010 011110 100001 101101 110011

Jah ich will trynen... Die Leute wie macht scheisse in dem Grünen.

Reply 49 of 96, by RJDog

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hard1k wrote:

MuntBlaster?..

PhilsComputerLab wrote:

MB-32

MB-32 = MuntBlaster-32
32 because... Cortex A7 is 32 bit processor.... I guess

Sold! (or until something better comes to mind)

Reply 50 of 96, by RJDog

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First draft of the WaveTable-to-OrangePiZero card complete; the host board (i.e. the board this card will go in to make it a stand-alone unit) yet to come.

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Reply 52 of 96, by hard1k

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Maybe I will be totally wrong here (as I'm not a hardware design engineer), but looking at the Orange Pi Zero picture the lower 26-pin header ("expansion port") on the MB-32 seems to be misplaced by 1 pin to the left - judjing from mutual placement of this header and the serial debug port as well as its alignment against the upper 13-pin "function interface".

New sound card project: AWE64 Legacy
Please have a look at my wishlist (hosted at Amibay)

Reply 53 of 96, by RJDog

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hard1k wrote:

but looking at the Orange Pi Zero picture the lower 26-pin header ("expansion port") on the MB-32 seems to be misplaced by 1 pin to the left

Holy buckets of earth, batman! You are exactly correct... good catch. Now I feel like an idiot. Not sure how I screwed that up so badly in the footprint...

Reply 54 of 96, by hard1k

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Don't worry, that happens 😀
When we produced the first batch of the GUS PnP RAM Adapter, somehow we chose the wrong thickness for the PCB - 0,8mm instead of 1,0mm. We had to manually add additional solder to the contacts in order for the adapter to sit well in the SIMM sockets, otherwise they just fell out...

You're welcome 😀

New sound card project: AWE64 Legacy
Please have a look at my wishlist (hosted at Amibay)

Reply 55 of 96, by RJDog

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Well... here is the updated version, this time with the correct footprint for the Orange Pi Zero. Still working on the host board. Thanks again, hard1k, for catching the misalignment.

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Reply 57 of 96, by RJDog

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Ariakos wrote:

This is a neat project. But the things I would do for an MT-32 in a PCMCIA form, though... 🤑

Well.. there do seem to exist PCMCIA MIDI cards....

But in other news, I have discovered a critical error in my design... my current design is based on the assumption that the Orange Pi Zero accepts 5V on the GPIO. It does not. It is 3.3V and apparently is not super tolerant of higher voltages. I'll have to rethink this.. implement a logic level converter or something...

Reply 59 of 96, by RJDog

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Yeah, the MOSFET route seems to be a bit on the expensive side, but doable, and quick googling seems to indicate its a popular solution.

I am thinking about using some non-inverting buffer logic chips, i.e. the 74LV125A can operate at and output 3.3V but inputs accept up to 5.5V regardless of Vcc; and 74HCT125N can operate at and output 5V and inputs accept as low as 2.1V for "high" signal. My biggest concern would be to make sure the buffers can switch fast enough to accomodate the 31250 baud rate. The TI part I'm looking at says its switching time is 4.7ns, which equates to roughly 2MHz, so that should be okay, I think?