Re: The Soundblaster DSP project
Posted on 2023-10-14, 03:22
Source code update. small optimizations with MACRO usage - much easier to read and understand, looks nicer
Re: The Soundblaster DSP project
Posted on 2023-10-13, 21:58
I actually have no idea of the specifics but I don't think that the atmega328 used has a large ram buffer - Perhaps it is large enough to avoid triggering the overflow , I can't see how the delay could be more than second or so? I guess we'll find out once more details are announced. Btw I kinda …
Re: The Soundblaster DSP project
Posted on 2023-10-13, 21:31
@Maelgrum check this out: Roland MT-32 Buffer overflow Hardware Fix AFAIK only the 1st generation of MT-32s are affected by this speed issue so by patching the unit you effectively make it "speed compatible" with whatever software/hardware/dumb/smart MPU solution exists out there. At some point …
Re: The Soundblaster DSP project
Posted on 2023-10-13, 20:43
Thinking about hardware MPU... We have HardMPU, great project, but it can't do midi output stream throttling, to solve early MT-32 buffer overflow issue (as far as I know, please correct me if I am wrong). So some project with HardMpu code and modifications on hard and soft side to do such …
Re: The Soundblaster DSP project
Posted on 2023-10-13, 20:13
To @mattw, you miss one thing - MPU dataflow is controlled by 2 bits in MPU status register (0x331) So you cannot read MPU data port, until Status port shows that data is present in data register. yep, it seems that way, using 'Debug.exe' for the test - i shouldn't do '-o 331 ac' and then …
Re: The Soundblaster DSP project
Posted on 2023-10-13, 20:08
To @mattw, you miss one thing - MPU dataflow is controlled by 2 bits in MPU status register (0x331) So you cannot read MPU data port, until Status port shows that data is present in data register. Port 0x331 is command/status. Then you write to it - MPU commands written. Then you read from it - it …
Re: The Soundblaster DSP project
Posted on 2023-10-13, 19:29
Not sure about this. Need to check it with HardMPU source code )) at least I got totally lost now - I mean what those known "Fake ACK" cards do more then? I mean as far as I understand from what @Cloudschatze wrote and based on my test results, the "Fake ACK" cards transmits electrically out what …
Re: The Soundblaster DSP project
Posted on 2023-10-13, 19:00
mattw wrote on 2023-10-13, 18:51: Exactly, but SysEX messages are considered MIDI-Data and not commands, correct or not? Not sure about this. Need to check it with HardMPU source code. [EDIT] looks like it is in midi-data stream
Re: The Soundblaster DSP project
Posted on 2023-10-13, 18:56
mattw wrote on 2023-10-13, 18:51: what you were sending out and how you were sending it out via the Loopback during the ROM dump hack? Midi data, of course, port 0x330
Re: The Soundblaster DSP project
Posted on 2023-10-13, 18:48
essentially, what is needed is Commands written to IOPort 0x331 that are not really acknowledged (they look like acknowledged based on the value in IOPort 0x330, but that is just left-over from the previously properly ACK command, i.e. "residual ACK") be forced to be electrically send out via the …
Re: The Soundblaster DSP project
Posted on 2023-10-13, 18:16
@Maelgrum : based on the above findings do you think you can as 1st step mod V4.13 to not leave any "residual" ACK, i.e. after 0xFE is in the IOPort 0x330 Xreg and the register is read, set its value back to 0xFF (or to 0x00 - I am not sure which one is the correct to remove the ACK) or something …
Re: The Soundblaster DSP project
Posted on 2023-10-13, 16:45
hmm, now the question is what is the best we can do with just ability to read IO port 0x330 - can we write 0x330 as well from the DSP or it's only read? IO 330 is bidirectional, of course. My notes: x-registers: 0 - read: command/data port (2xC on PC side) 1 - read: MPU-401 data register 2 - read: …
Re: The Soundblaster DSP project
Posted on 2023-10-13, 16:44
So it looks like Bus interface chip does all job interpreting MPU commands, and DSP fw got only one line (p1.6) from BIC, which is MPU UART mode is ON or OFF.
Re: The Soundblaster DSP project
Posted on 2023-10-13, 16:32
If any 0xAE byte is found in xregs.bin - its a good sign see the attached dump - 0xAE is there - I hope it's also on the right place and not some other 0xAE.... No luck - looks like x-regs are in range 0x00-0x1F, and 0x80-0x83 (ASP/CSP). No sign of MPU command port (IO 331) register present in x- …
Re: The Soundblaster DSP project
Posted on 2023-10-13, 16:08
Byte written to IO port 0x331 - x-reg is unknown, and maybe not exists. Testing is needed )) thank you, if you come up with a test procedure - let us know - I am sure here are more people, than just me, always ready to help and test with whatever they can. You can try this, output is xregs.bin file …
Re: The Soundblaster DSP project
Posted on 2023-10-13, 15:54
read from x-reg 0x02 I guess my question is (if I am not totally confused and mistaken) : which 'x-reg' register corresponds to the content written to IO Port 0x330 and which one to 0x331? isn't for the "Fake ACK" sufficient just to always return 0xFE to IO Port 0x330, no matter what was requested …
Re: The Soundblaster DSP project
Posted on 2023-10-13, 15:39
Does the patched firmware also fix the 'type 2' hanging note bug? And can you explain how the presence of the CT1747 chip fixes the type 1 bug? Yes it does "And can you explain how the presence of the CT1747 chip fixes the type 1 bug?" The guy asked about the second question that was not answered. …
Re: The Soundblaster DSP project
Posted on 2023-10-13, 13:22
Can someone write in a nutshell what this does, where it applies, what you need... ? If possible in the 1st post. Thanks 1. New DSP firmware for SB16/AWEs fixes some bugs (including infamous hanging note bug) 2. Applies to all Sb16/aWEs with discrete DSP. 3. You need to desolder old DSP, install …
Re: The Soundblaster DSP project
Posted on 2023-10-13, 13:01
I hope the AT89S52 chips would arrive soon same from my side. BTW, @Maelgrum if you need a tester for "6 clocks cycles"-mode, i.e. if you believe anything can be fixed/improved that way, just keep in mind I ordered "AT89C51RC2". How hard would it be to implement fake ACK for the MPU? The same way …
Re: The Soundblaster DSP project
Posted on 2023-10-12, 18:16
This is release of 'dsp_v413_maelgrum' version 5 Changes from classic V4.13: 1. Hanging note bug fixed 2. ADPCM decoding bug fixed 3. ALL interrupt handlers are fixed (PSW bug and R0 used before pushed to stack bugs) 4. Numerous small scale optimizations (LJMP to RET is changed to RET, e.t.c.) Must …
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