From 3ef319f0af33d1e805b28b4c70efe990bb79c8ee Mon Sep 17 00:00:00 2001 From: mamehaze Date: Sun, 29 Mar 2015 22:41:06 +0100 Subject: [PATCH] spider service mode trigger is non-obvious, document it (nw) --- src/mame/drivers/twins.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/src/mame/drivers/twins.c b/src/mame/drivers/twins.c index 2aba06aa999..8f58e5b4b91 100644 --- a/src/mame/drivers/twins.c +++ b/src/mame/drivers/twins.c @@ -52,6 +52,9 @@ It is possible the Twins PCB has them too and doesn't use them. Twins (set 2) is significantly changed hardware, uses a regular RAMDAC hookup for plaette etc. +To access Service Mode in Spider you must boot with P1 Left and P1 Right held down, +this requires the -joystick_contradictory switch on the commandline. + */ @@ -506,11 +509,14 @@ WRITE16_MEMBER(twins_state::spider_port_1c_w) // game is only animating sprites at 30fps, maybe there's some double buffering too? +// data written is always 00, only seems to want the upper layer to be cleared +// otherwise you get garbage sprites between rounds and the bg incorrectly wiped + UINT16* vram; - if (m_videorambank & 1) +// if (m_videorambank & 1) vram = m_videoram2; - else - vram = m_videoram; +// else +// vram = m_videoram; for (int i = 0; i < 0x8000; i++) {