Hmm this same firmware and microcontroller could also be made into a simple USB-serial adapter that could solve the problem of connecting older RS232 synths to newer PCs without serial ports. The microcontroller is $12 and all that would be required beyond that would be an RS232 level converter, crytal, regulator and a few caps and resistors. My intention is to build a simple and affordable USB speech synth with onboard USB audio codec, it will be sold on ebay in low volume, probably in the price range of $150. Since the same microcontroller and firmware would solve the problem of supporting older RS232 synths on PCs without serial ports, I could also make a serial dongle with same firmware and R232 port for connecting to synth, I could probably do that at a price point of $40 for an adapter. Both of these would appear as generic virtual USB serial COM port due to proper implementation of the USB CDC ACM in firmware. No special drivers will be needed, only the driver code specific to the speech hardware. As mentioned several weeks ago, my longer term goal is to make a audio based PDA with speech hardware onboard, but I need to start with simpler ideas to get the ball rolling. I am already working with GSM/GPRS hardware that provides both voice and data support, this is intented to be an add-on to the audio PDA but that is quite a ways into the future. It is actually very easy to add phone capability these days. In fact it can be done also entirely using standard USB drivers, where the data connection is USB CDC (again just a virtual COM port, looks like a modem), and the USB audio drivers. Short term, a USB adapter dongle that would work with speakup connecting to older synths, and also a doubletalk based USB synthesizer with audio codec are in the works. I actually have all the hardware working together, just not in a desireable form factor. -- Doug
