summaryrefslogtreecommitdiffstatshomepage
diff options
context:
space:
mode:
author mamehaze <mamehaze@users.noreply.github.com>2015-03-29 22:41:06 +0100
committer mamehaze <mamehaze@users.noreply.github.com>2015-03-29 22:41:06 +0100
commit3ef319f0af33d1e805b28b4c70efe990bb79c8ee (patch)
tree5862667f0fca47228418833e61b7faa8b966b80b
parent47ab93edd2179092721a6f4a183f6c2a16ab2430 (diff)
spider service mode trigger is non-obvious, document it (nw)
-rw-r--r--src/mame/drivers/twins.c12
1 files 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++)
{