Hi people,
I am in my lab right now (yes, in a Sunday), this was the only way for having some spare time for mounting a small circuit board for testing the PSG implemented in an FPGA. The VHDL code was already exhaustively tested through out simulations (using Xilinx CAD software, Xilinx Foundation 3.1i), so what was missing is a connection between the FPGA board and the MSX1 (Brazilian Expert 1.0 model). I finished the connections some minutes ago. The scheme is the following: one removes the original PSG, connects the DIP40 socket that I am using, which has the wiring ready for the FPGA board (Xilinx XCS30XL-VQ100), turns on the MSX, loads the FPGA configuration (in this moment the FPGA becomes from a unuseful chip into an authentic PSG-replacement), gives a reset in the MSX and it works fine! Right now I am listening for the thousand time the main theme from Venom Strikes Back, which is a great test, because it uses the 3 audio channels, the envelope generator and the noise channel. As I expected, everything works fine, which shows that the simulations are very efficient. And it has an advantage: the original PSG cannot work with a clock higher than 4MHz, this PSG that I developed goes until 60MHz (using the FPGA indicated above, I already made other simulations with other chips, and I seems to work above 100MHz of maximum clock!!!) The the result is the following: now we have a PSG replacement, and it can be used in any MSX, whatever the clock is. In this case, we do not need to insert wait-states or any other bad trick when someone want to use a faster CPU (like Z180, Z380 or others). For those who does not understang what I made, in the next weeks I will take some pictures and put them in a directory in my homepage. In the next Jau' MSX meeting I will make a presentation and a demonstration of this prototype. I guarantee that it will be very interesting! Now let's go to the questions and answers! Greetings from Brazil. ----------------------------------------------------------- Marco Antonio Simon Dal Poz http://www.lsi.usp.br/~mdalpoz [EMAIL PROTECTED] "old Fords never die, just get better" _______________________________________________ MSX mailing list ([EMAIL PROTECTED]) Info page: http://lists.stack.nl/mailman/listinfo/msx
