summaryrefslogtreecommitdiffstats
path: root/src/mame/includes/starshp1.h
diff options
context:
space:
mode:
authorGravatarGravatar Frank Palazzolo <frank@avoidspikes.com>2017-06-06 00:38:10 -0400
committerGravatarGravatar Vas Crabb <cuavas@users.noreply.github.com>2017-06-06 14:38:10 +1000
commit101cc6720263a729a28bf4131b941d182de91422 (patch)
tree64845d2dc561b206b972409f1260fcad3e007cc9 /src/mame/includes/starshp1.h
parenta29e43a74cecc09815aa1b21e99d4f64968f7fc5 (diff)
Fix mametesters bug #3041 (#2359)
* starshp1: Fast/Slow control from toggled to momentary, as in real game * Update clocks per latest information * Add note about Throttle Level behaviour * Change format of comments
Diffstat (limited to 'src/mame/includes/starshp1.h')
-rw-r--r--src/mame/includes/starshp1.h16
1 files changed, 12 insertions, 4 deletions
diff --git a/src/mame/includes/starshp1.h b/src/mame/includes/starshp1.h
index fc4e239271d..a376c2ab8ec 100644
--- a/src/mame/includes/starshp1.h
+++ b/src/mame/includes/starshp1.h
@@ -14,8 +14,16 @@
* probably too low. I suspect that screen is not really
* 512 pixels wide -- most likely 384, which would give 60Hz
*
- * Some of the graphics, like the starfield, is clocked with the
- * 12MHz signal, effectively doubling the horizontal resolution
+ * Based on photographs of the PCB, and analysis of videos of
+ * actual gameplay, the horizontal screen really is 384 clocks.
+ *
+ * However, some of the graphics, like the starfield, are
+ * clocked with the 12MHz signal. This effectively doubles
+ * the horizontal resolution:
+ *
+ * 6.048Mhz clocks 12.096Mhz clocks
+ * Horizontal Visible Area 384 (0x180) 768 (0x300)
+ * Horizontal Blanking Time 128 (0x080) 256 (0x100)
*/
#include "sound/discrete.h"
@@ -24,8 +32,8 @@
#define STARSHP1_MASTER_CLOCK (12096000)
#define STARSHP1_CPU_CLOCK (STARSHP1_MASTER_CLOCK / 16)
-#define STARSHP1_PIXEL_CLOCK (STARSHP1_MASTER_CLOCK / 2)
-#define STARSHP1_HTOTAL (0x200)
+#define STARSHP1_PIXEL_CLOCK (STARSHP1_MASTER_CLOCK)
+#define STARSHP1_HTOTAL (0x300)
#define STARSHP1_HBEND (0x000)
#define STARSHP1_HBSTART (0x200)
#define STARSHP1_VTOTAL (0x106)