First post, by tbcarey
..and now for something completely off-topic. I realize this may not be the best place to ask for help regarding an actual MT-32, given that this forum is about Munt/MT-32 emulation, but on the other hand it seems likely that a greater number of people here will own actual MT-32s or similar modules than elsewhere.
I own three sound modules - an MT-32, an SC-88, and an SC-88ST Pro. My laptop has no MIDI port [obviously], so I've had to connect the SC-88 to my laptop via a USB-to-Serial Port converter and the SC-88's 'Computer'/serial port. I then chained the MT-32 to the SC-88's MIDI Out/Thru in Out mode [according to all of the SC manuals I've read, they don't pass on 'Computer port' MIDI data unless in Out mode -- Thru mode only passes data from MIDI In A], and chained the SC-88ST Pro to the MT-32's MIDI Thru.
My problem is this: although I've set up the serial port to work at 9600 baud without flow control [slow enough not to cause buffer overflows when SysEx data is sent to the MT-32], and I've set up the SC-88 Serial Port drivers to use RTS/CTS Flow Control, I still receive errors when using the MT-32 under DOSBox or VDMSound [or in Winamp playing an MT-32 MIDI file, etc.]. Strangely enough, I get no errors when using it under ScummVM in Native MT-32 mode.
The error I receive is "Exc. Checksum error". This happens whenever SysEx data is sent to the MT-32 -- especially when games first initialize. In LucasArts games that utilize SysEx instruments like Monkey Island 2, it doesn't seem to be a problem. The MT-32 outputs the error but then all the instruments load properly and I notice no errors. In games like Silpheed or other Sierra games, however, only a number of SysEx instruments load properly and the rest remain the defaults, which is a problem. As I said before, the error never occurs under ScummVM and all instruments load properly. I don't know if this is because ScummVM sends data at a much slower rate than the other programs, or what.
At any rate, does anyone know what's causing this? Is it because I'm passing data to the MT-32 via the SC-88 which is using the 'Computer port'? Is there any way around this that anyone knows of? Will I have to buy a USB-to-MIDI adapter instead and chain everything else through the MT-32 like I did on my desktop? Any help would be greatly appreciated! Thanks guys.
