NEC μPD77P25GW ROM dumping

[Treehouseman]

I have an Aicom Accent Messenger IC speech synthesizer that is a PCMCIA card. The unit uses a NEC μPD77P25GW DSP for the spech generation and I have a feeling that it's designed to be a Votrax SC-02/SSI-263 simulation. Aicom had other models that I found mentions being Votrax based units, but bing a PCMCIA card they couldn't use the normal DIP package the Votrax came in. I've gotten the unit working and the speech seems quite similar to a SC-02. I'm wanting to try to get a dump of the program and data rom, but these chips support a read protect. I saw that these were used in a bunch of SNES cartridges as the DSP-1 chip and in some arcade machines, and there's dumps of a lot of the SNES games but seems like some of those were done via decapping since they were mask rom. This is the EPROM variant, so I'd have to manually read it. I'm wondering if anyone might know of a way to bypass the read protect on these, I'm wanting to document and save as much as possible about this unit. Also if anyone has any info on Aicom and it's other products that could also be very helpful.

At the moment I'm going to hold off on attempts to remove the chip until I get a chance to do some probing and data logging to look into the way the computer talks to the unit, but in the end it I want to try to get a rom dump to preserve it. Aicom had this as a direct alternative to their standalone models, realistically it would be meant to sound the exact same, and if the other models used a Votrax SC-02, it would stand to be that this is a DSP recreation. There's already emulators for this DSP, if it is a Votrax substitute this could lead to fun software emulation of a now expensive speech chip.

This is the floppy images I have, pictures of the inside of the device, and audio of the demo text files played via the demo basic program
http://id10t-tech.com/filedump/Aicom%20Messenger%20IC.zip