video/upd7220.cpp: horizontal multiplier is x16 if in gfx mode, x8 ot…

…herwise * fix microbx2 and pc9801:diremono
mamedev · Nov 2, 2024 · 7149fab · 7149fab
1 parent e46068b
commit 7149fab
Show file tree

Hide file tree

Showing 2 changed files with 7 additions and 13 deletions.
diff --git a/src/devices/video/upd7220.cpp b/src/devices/video/upd7220.cpp
@@ -383,17 +383,11 @@ inline void upd7220_device::update_blank_timer(int state)
 
 inline void upd7220_device::recompute_parameters()
 {
-	int horiz_mult = 16, vert_mult = 1;
-	/* TODO: assume that the pitch also controls number of horizontal pixels in a single cell */
-	// horiz_mult = 4 if both mixed and interlace?
-	if((m_mode & UPD7220_MODE_DISPLAY_MASK) == UPD7220_MODE_DISPLAY_MIXED)
-		horiz_mult = 8;
-	else if((m_mode & UPD7220_MODE_INTERLACE_MASK) == UPD7220_MODE_INTERLACE_ON)
-	{
-		// in interlaced mode every line contains both fields
-		horiz_mult = 8; // TODO this breaks microbx2, compis uhrg video, characters are 16 pixels wide in interlaced mode too
-		vert_mult = 2;
-	}
+	// microbx2 wants horizontal multiplier of x16
+	// pc9801:diremono sets up m_mode to be specifically in character mode, wanting x8 here
+	// TODO: verify compis uhrg video & high reso Hyper 98
+	const int horiz_mult = (m_mode & UPD7220_MODE_DISPLAY_MASK) == UPD7220_MODE_DISPLAY_GRAPHICS ? 16 : 8;
+	const int vert_mult = (m_mode & UPD7220_MODE_INTERLACE_MASK) == UPD7220_MODE_INTERLACE_ON ? 2 : 1;
 
 	int horiz_pix_total = (m_hs + m_hbp + m_hfp + m_aw) * horiz_mult;
 	int vert_pix_total = (m_vs + m_vbp + m_al + m_vfp) * vert_mult;

diff --git a/src/mame/misc/microbox2.cpp b/src/mame/misc/microbox2.cpp
@@ -302,10 +302,10 @@ void microbx2_state::microbx2(machine_config &config)
 	m_maincpu->set_addrmap(AS_PROGRAM, &microbx2_state::mem_map);
 
 	screen_device &screen(SCREEN(config, "screen", SCREEN_TYPE_RASTER));
-	screen.set_raw(16_MHz_XTAL, 1024, 0, 768, 674, 31, 607);
+	screen.set_raw(16_MHz_XTAL / 3, 1024, 0, 768, 674, 31, 607);
 	screen.set_screen_update("gdc", FUNC(upd7220a_device::screen_update));
 
-	upd7220a_device &gdc(UPD7220A(config, "gdc", 16_MHz_XTAL / 8));
+	upd7220a_device &gdc(UPD7220A(config, "gdc", 16_MHz_XTAL / 3)); // unverified clock, hand tuned for ~60 Hz
 	gdc.set_addrmap(0, &microbx2_state::upd7220_map);
 	gdc.set_display_pixels(FUNC(microbx2_state::display_pixels));
 	gdc.set_screen("screen");