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fidel68: forgot to copypaste irq note from berger (nw)

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hap 2016-12-29 17:49:35 +01:00
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7
src/mame/drivers/fidel68k.cpp
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@ -56,10 +56,9 @@ Hardware info:
- OKI M82C51A-2 USART, 4.9152MHz XTAL
- other special: magnet sensors, external module slot, serial port
IRQ source is unknown. Several possibilities:
- NE555 timer IC
- MM/SN74HC4060 binary counter IC (near the M82C51A)
- one of the XTALs, plus divider of course
IRQ source is a 4,9152MHz quartz crystal (Y3) connected to a 74HC4060 (U8,
ripple counter/divider). From Q12 output (counter=8192) we obtain the IRQ signal
applied to IPL1 of 68000 (pin 24) 4,9152 MHz / 8192 = 600 Hz.
The module slot pinout is different from SCC series. The data on those appears
to be compatible with EAG though and will load fine with an adapter.