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author davidhay <davidhay@localhost>2008-10-12 09:18:59 +0000
committer davidhay <davidhay@localhost>2008-10-12 09:18:59 +0000
commitcceb21bd99912d9ab91fb3402ee5bbd7fb99635f (patch)
tree8ff97f1a7fcbbb55a7b1a94f667e3bf9dcd3195d
parentea05fb2e3817e0a5d113e4c9e39b71b62fc8139d (diff)
added a note about C2 IRQ6 for future reference when rewriting all this.
-rw-r--r--src/mame/drivers/megadriv.c13
1 files changed, 13 insertions, 0 deletions
diff --git a/src/mame/drivers/megadriv.c b/src/mame/drivers/megadriv.c
index 881a36d5ed0..ec08573542b 100644
--- a/src/mame/drivers/megadriv.c
+++ b/src/mame/drivers/megadriv.c
@@ -41,6 +41,19 @@
Known Non-Issues (confirmed on Real Genesis)
Castlevania - Bloodlines (U) [!] - Pause text is missing on upside down level
Blood Shot (E) (M4) [!] - corrupt texture in level 1 is correct...
+
+Cleanup / Rewrite notes:
+
+On SegaC2 the VDP never turns on the IRQ6 enable register
+ This is because on the real PCB that line of the VDP isn't
+ connected. Instead the IRQ6 interrupt is triggered by the
+ line that is used to generate the Z80 interrupt on a standard
+ genesis. (Once, every frame, on screenline 224)
+
+ I should provide interrupt callback functions for each
+ vdp line state change, which can be configured in the init
+ rather than hardcoding them.
+
*/