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lrw80, radionic: Better conjectures regarding clocks (nw)

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AJR 2018-05-11 09:18:00 -04:00
parent c66ca3bc64
commit b561b470c1
1 changed files with 4 additions and 2 deletions
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6
src/mame/drivers/trs80.cpp
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@ -728,7 +728,7 @@ MACHINE_CONFIG_START(trs80_state::lnw80)
MCFG_PALETTE_INIT_OWNER(trs80_state,lnw80)
MCFG_SCREEN_MODIFY("screen")
MCFG_SCREEN_RAW_PARAMS(3.579545_MHz_XTAL * 3, 682, 0, 480, 264, 0, 192) // 10.738MHz generated by tank circuit (top left of page 2 of schematics)
// LNW80 Theory of Operations gives H and V periods as 15.750kHz and 59.66Hz, which don't seem exactly divisible
// LNW80 Theory of Operations gives H and V periods as 15.750kHz and 59.66Hz, probably due to rounding the calculated ~15.7468kHz to 4 figures
MCFG_SCREEN_UPDATE_DRIVER(trs80_state, screen_update_lnw80)
MACHINE_CONFIG_END
@ -736,7 +736,9 @@ MACHINE_CONFIG_START(trs80_state::radionic)
model1(config);
MCFG_DEVICE_MODIFY("maincpu")
MCFG_DEVICE_CLOCK(12_MHz_XTAL / 6) // or 3.579MHz / 2 (selectable?)
// Komtek I "User Friendly Manual" calls for "Z80 running at 1.97 MHz." Schematics mark XTAL as 12 MHz, but is that rounded off?
// Komtek I "User Friendly Manual" calls for "Z80 running at 1.97 MHz." This likely refers to an alternate NTSC version
// whose master clock was approximately 11.8005 MHz (6 times ~1.966 MHz and 750 times 15.734 kHz). Though the schematics
// provide the main XTAL frequency as 12 MHz, that they also include a 3.579 MHz XTAL suggests this possibility.
MCFG_DEVICE_PERIODIC_INT_DRIVER(trs80_state, nmi_line_pulse, 12_MHz_XTAL / 12 / 16384)
MCFG_SCREEN_MODIFY("screen")