Último mensaje de la página anterior:
pser1 escribió:Clearly the FMAV77 requires that strange sequence of operations just to send a value to a register, mainly
- Select the register with, let's say, three POKEs
- Write the data with another set of three POKEs
Of course!!! Silly me.
Those POKE's are the commands. So the PSG control register is not directly mapped to the sound chip, it's a multiplexor of some kind.
Put the data on data register and then
Command 3 = address register
Command 0 = high impedance -> (a "send command", something bus related, i suppose)
And for sending sound data, Command 2 (write data) and Command 0 (high impedance).
Instead of just putting the control register directly as 0-13 register.
I suppose this weird implementation is for bus implementation reasons or an "abstracting hw" approach.