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-rw-r--r--src/mame/drivers/expro02.c14
1 files changed, 13 insertions, 1 deletions
diff --git a/src/mame/drivers/expro02.c b/src/mame/drivers/expro02.c
index de6de10e195..eed9561ab6a 100644
--- a/src/mame/drivers/expro02.c
+++ b/src/mame/drivers/expro02.c
@@ -43,11 +43,23 @@ EXPRO-02
Notes
-----
+ GP-U27/U41 - These are DIP40 chips, but are not MCUs because there is no stable
+ clock input on any of the pins of these chips. They're not ROMs either
+ because the pinout doesn't match any known EPROMs.
+ There are no markings on the chips other than 'GP-U27' & 'GP-U41'
+ If GP-U41 is removed, on bootup the PCB gives an error 'BG ERROR' and
+ a memory address. If GP-U27 is removed, the PCB works but there are no
+ background graphics.
+
68000 clock - 12.0MHz
CALC1-CHIP clock - 16.0MHz
GP-U41 clocks - pins 21 & 22 - 12.0MHz, pins 1 & 2 - 6.0MHz, pins 8 & 9 - 15.6249kHz (HSync?)
GP-U27 clock - none (so it's not an MCU)
- OKI M6295 clock - 2.0MHz (12/6). pin7 = low
+
+ (TODO: which is correct?)
+ OKI M6295 clock - 2.0MHz (12/6). pin7 = low
+ OKI M6295 clock - 2.000 MHz [16/8]. Sample rate 2000000/165
+
VSync - 60Hz
HSync - 15.68kHz
MC-8282 - Kaneko custom I/O JAMMA ceramic module