TI's DAC/ADC

[in8regs]

Not knowing anything about hardware. Too bad the load interrupt signal is not on the cartridge port.

That way some genius could put a timer on a cartridge PCB for generating the load interrupt.

ok, this would require 32K memory as the vector is located at >FFFD and >FFFE.

 

hhmm, thinking about it more I recall we had some discussions about a cartridge PCB that plugs into the sideport.

 

Microcontrollers have timers, dac, adcs, room for memory expansion, etc. I was looking at cf7+, it's nice but what I'd want is SD, which lots of the other platforms have had done for them, interfaced via cart & floppy, like this: http://www.c64-wiki.com/index.php/MMC2IEC. I immediately thought of the expansion compartment of the speech adapter for where I'd put it, and would want an SD cartridge(or a cartridge tethered to the uc in the speech synth) as well. The mmc2iec hardware likely could be used as is, just needing the uc code rewritten to emulate ti's disk controller/disk instead of c64, then wire it to the needed pins. That's nice, but in my view, all the sd/cf/etc devices are over priced, wanting $45-150. I got curious, so I looked at microcontrollers and interfacing with sd, which there are many cheap solutions, relatively easy sd hookup, already worked out with howtos. I eventually spied TI's msp430, their new MSP430G2xx go for 0.25c per 1000, and single 430s go for as little as $1.25 at places like mouser, even better, many versions are available as free samples from TI. SD and the 430's require a lot less soldering and space than the FPGA setup the cf7+ uses. Did I forget to mention? The 430 is essentially the microcontroller version of the 9900:) Albeit modified, not compatible. Though a microchip or pic uc might be a better fit, the idea of the 430 being used for interfacing to the 4a is appealing:) Anyway, I even saw a PIC uc comparable to the low end 430's used to playback raw audio at 8bit 8khz off of an interfaced sd. Using a uc could be viewed as cheating/not as hard core, I suppose:) Though I believe there was an external DAC add-on back in the day.

 

A compromise to roll your own are the $20 development boards, like starting with the mmc2iec, but need to add the sd interface.

Edited April 2, 2010 by in8regs