diff --git a/src/mame/drivers/votrpss.cpp b/src/mame/drivers/votrpss.cpp index d6f5ce0f253..10907718965 100644 --- a/src/mame/drivers/votrpss.cpp +++ b/src/mame/drivers/votrpss.cpp @@ -9,52 +9,39 @@ * * The votrax PSS was sold from around 35th week of 1982 until october, 1990 (LONG product life) - timer0 = baud clock - timer1 = pitch (duty cycle output to modify RC) - timer2 = volume (duty cycle output to control trans. gate which does vol. control) - portb: pin 6 through pin 13 of parallel port - portc 0 = NC, 1 = GND, 2 = pin 5, 3 = /RXINTEN, 4 = pin 15, 5 = pin 14 through inverter, 6 = 8910 enable, 7 = from pin 4 through inverter (I believe that's for the parallel port) - porta: pin 16 through 23 of parallel port - that's the 8255 - on the AY-3-8910: - IOA0-A5 = phoneme # - IOA6 = strobe (SC-01) - IOA7 = vochord control, 0 = off, 1 = on - IOB0-IOB7 = dip switches - there ya go, complete IO port map - cool :) - I pinned the IO to the serial port from the 8251 but I don't think it's too useful - eh, its useful - I drew out the schematic for the analog section - oh that will be useful - but I didn't draw out the digital part, just made an I/O and memory map but I can't find them - i also see the ay is running at 2 MHz - sounds about right - got it - I drew out the clocking section too - 8MHz xtal - 4MHz for the Z80 - 2MHz for the 8253 and '8910 - then the dividers also generate the system reset signals for the 8251 - and a periodic IRQ - on the z80? - ok how does that work? - IRQ rate is umm - 122Hz - (8MHz / 65536) - oh the 8251 is not reset by the counters - it just takes a positive reset off an inverter that resets the counters - PIT2 is gated by 8MHz / 256 - PIT1 is gated by 8MHz / 4096 - PIT0 is not gated - (i.e. it always runs) - oh boy, this is sounding more fun by the minute - aaand your luck is about to run out - that's all I got - thats good enough, saved me a lot of work - but that's everything you need - yeah +Main xtal is 8MHz +AY-3-8910 and i8253 clock is running at 2 MHz (xtal/4) +Z80A is runing at 4MHz (xtal/2) +clock dividers also generate the system reset signals for the 8251 and and a periodic IRQ at 122Hz (xtal/65536) +I8253: +Timer0 = Baud Clock, not gated (constantly on) +Timer1 = output to transistor chopper on clock input to sc-01-a to control pitch; gated by xtal/256 +Timer2 = output to transistor chopper on output of sc-01-a to control volume; gated by xtal/4096 + +I8255 ports: +PortA 0:7 = pins 16 thru 23 of parallel port +PortB 0:7 = pins 6 thru 13 of parallel port +PortC = + 0 = NC + 1 = GND + 2 = pin 5 of parallel port + 3 = /RXINTEN + 4 = pin 15 of parallel port + 5 = pin 14 of parallel port through inverter + 6 = ay-3-8910 enable (which pin? BC1?) + 7 = input from parallel port pin 4 through inverter + +AY-3-8910 I/O ports: + IOA is in output mode + IOA0-A5 = phoneme # + IOA6 = strobe (SC-01) + IOA7 = vochord control, 0 = off, 1 = on + IOB is in input mode + IOB0-IOB7 = dip switches + +I8251 UART: + RESET is taken from teh same inverter that resets the counters Things to be looked at: - Serial doesn't work, so has been disabled.