I got the final boards about a week and half ago, assembled one, and gave it a test. Everything worked as it should.
So my plan now is to build up a 2nd one and drop that off with someone I consider to be the utmost authority on the 1200XL, and who has gotta have the largest collection in the known world, and perhaps the entire universe - Bob Woolley.
Currently I'm waiting for some SRAM chips to show up from China (both the 512K and 64K chips). I'm hoping that I get a good batch, although if not and they turn out to be fakes I won't be out much in $$$.
The 512K chips are in current production and readily available from the likes of Digi-Key and Mouser, but I'm looking for a deal so I thought what the heck I'd give AliExpress a try to see if I get lucky.
The 64K SRAM is a different story, having been out of production for years. However I've bought these in the past from multiple electronics surplus electronics sellers without even one failure, so I'm hoping for the same on this go around from an eBay seller
The great thing about switching from DRAM to SRAM, was that I got rid of the last remnant of video noise producing hardware on my 1200XL, and the results were fantastic!
New Project
So as the 1200XL-1mb project gets wrapped up, I'm off on another. This time I've decided to integrate a MIDI Player aspect into the NUCplus4's FujiNet module.
Since the NUCplus4's FujiNet module already plugs into the entire SIO bus, it has audio input capabilities via the SIO's Audio Input pin. This was already taken advantage of by FujiNet with the Disk Rotate being called out by the emulated S.A.M. voice in the ESP-32's firmware. And it's a simple matter of mixing in additional audio devices through this same pin (e.g.; MIDI Synthesizer).
Now it just so happens that there is a very inexpensive encased module that incorporates the SAM2695 MIDI Synthesizer chip that goes for cheap, and is manufactured for M5STACK in China.
So my plan now is to build up a 2nd one and drop that off with someone I consider to be the utmost authority on the 1200XL, and who has gotta have the largest collection in the known world, and perhaps the entire universe - Bob Woolley.
Currently I'm waiting for some SRAM chips to show up from China (both the 512K and 64K chips). I'm hoping that I get a good batch, although if not and they turn out to be fakes I won't be out much in $$$.
The 512K chips are in current production and readily available from the likes of Digi-Key and Mouser, but I'm looking for a deal so I thought what the heck I'd give AliExpress a try to see if I get lucky.
The 64K SRAM is a different story, having been out of production for years. However I've bought these in the past from multiple electronics surplus electronics sellers without even one failure, so I'm hoping for the same on this go around from an eBay seller
The great thing about switching from DRAM to SRAM, was that I got rid of the last remnant of video noise producing hardware on my 1200XL, and the results were fantastic!
New Project
So as the 1200XL-1mb project gets wrapped up, I'm off on another. This time I've decided to integrate a MIDI Player aspect into the NUCplus4's FujiNet module.
Since the NUCplus4's FujiNet module already plugs into the entire SIO bus, it has audio input capabilities via the SIO's Audio Input pin. This was already taken advantage of by FujiNet with the Disk Rotate being called out by the emulated S.A.M. voice in the ESP-32's firmware. And it's a simple matter of mixing in additional audio devices through this same pin (e.g.; MIDI Synthesizer).
Now it just so happens that there is a very inexpensive encased module that incorporates the SAM2695 MIDI Synthesizer chip that goes for cheap, and is manufactured for M5STACK in China.
- M5STACK P/N: U178
- Digi-Key P/N: 2221-U178-ND
- Mouser P/N: 170-U178
For our purposes the SAM2695 carrier PCB will get extracted from the plastic case it comes in, and with a small modification be incorporated into a brand new NUCplus4 FujiNet/MIDIplay board.
The original miniature 8 ohm speaker will get dispensed with and I'll be routing the Class D amplifier's mono output directly into the SIO Audio Input pin via a resistor mixing circuit.
At first I wasn't sure that this would work and actually provide good quality audio output, but after connecting it up to my LG 55" HDTV and Sony Sound Bar via a RetroScaler-2X video converter I was soon won over by the sheer clarity of the highs and the dynamic bass that this system combination was producing.
Luckily there was still a small fragment of real estate left inside the 576NUC+/NUCplus4 system that allowed the MIDI player to be added as an extension of the original FujiNet Module PCB.
PCB TOP VIEW
At the same time, an independent 3.3V regulated supply was added for the FujiNet side of things in order to correct some drop-out issues in FujiNet's operation that had been seen with the previous version.
Using the MI-PIC chip (PIC12F1572) incorporating the MIDI-CNTRL firmware to interface with the M5STACK MIDI-Synth module, adds a full MIDIMATE compatible connection scheme, as well as the ability to play an embedded start-up MIDI sound file if so desired.
- 31,250 Hz Synchronized MIDI-CLK tied into the SIO-CLK-IN pin.
- SIO-MOTOR enables the MIDI device to be on the SIO bus.
- Power-Up MIDI Intro tune is possible, same as other Mytek SIO2MIDI devices.
On item 3, currently three modes are offered in the firmware download, Silent, Atari, and MULE. I'll be experimenting down the road with the possibility of adding a more traditional computer start-up sound, to be both short in duration and subtle (with a low volume level).
New FujiNet/MIDIplay module schematic:
| NUCplus4_FujiNet-MIDIplay_schema.pdf |
EDIT (2/1/2025): Until such time that the official online FujiNet firmware has been updated past v1.4, the zipped file: fujinet-ATARI-v1.4.1_CKI-TEST.zip which is available in the NUCplus4 downloads section needs to be flashed for proper MIDIMATE usage. This file is part of the total firmware download file: NUCplus4_firmware_all.zip
Well that wraps it up for this post.
- Michael
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