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author AJR <ajrhacker@users.noreply.github.com>2019-07-02 10:15:02 -0400
committer AJR <ajrhacker@users.noreply.github.com>2019-07-02 10:16:40 -0400
commitf36763266f8593a8eac994dba3adf552c09b5029 (patch)
tree29c6ae9d2377a34ef169275a29a09e159a652143
parent886b94648edcefdbb0622f1e2c8d826f3fcfc998 (diff)
i8275: Calculate refresh rate from software-configured parameters
-rw-r--r--src/devices/video/i8275.cpp10
-rw-r--r--src/devices/video/i8275.h46
-rw-r--r--src/mame/machine/imds2ioc.cpp1
3 files changed, 30 insertions, 27 deletions
diff --git a/src/devices/video/i8275.cpp b/src/devices/video/i8275.cpp
index f640907635f..404a5743bd9 100644
--- a/src/devices/video/i8275.cpp
+++ b/src/devices/video/i8275.cpp
@@ -106,6 +106,7 @@ i8275_device::i8275_device(const machine_config &mconfig, device_type type, cons
m_write_hrtc(*this),
m_write_vrtc(*this),
m_write_lc(*this),
+ m_refresh_hack(false),
m_status(0),
m_param_idx(0),
m_param_end(0),
@@ -725,15 +726,14 @@ void i8275_device::recompute_parameters()
int horiz_pix_total = (CHARACTERS_PER_ROW + HRTC_COUNT) * m_hpixels_per_column;
int vert_pix_total = (CHARACTER_ROWS_PER_FRAME + VRTC_ROW_COUNT) * SCANLINES_PER_ROW;
- attoseconds_t refresh = screen().frame_period().attoseconds();
+ attotime refresh = clocks_to_attotime((CHARACTERS_PER_ROW + HRTC_COUNT) * vert_pix_total);
int max_visible_x = (CHARACTERS_PER_ROW * m_hpixels_per_column) - 1;
int max_visible_y = (CHARACTER_ROWS_PER_FRAME * SCANLINES_PER_ROW) - 1;
- LOG("width %u height %u max_x %u max_y %u refresh %f\n", horiz_pix_total, vert_pix_total, max_visible_x, max_visible_y, 1 / ATTOSECONDS_TO_DOUBLE(refresh));
+ LOG("width %u height %u max_x %u max_y %u refresh %f\n", horiz_pix_total, vert_pix_total, max_visible_x, max_visible_y, refresh.as_hz());
- rectangle visarea;
- visarea.set(0, max_visible_x, 0, max_visible_y);
- screen().configure(horiz_pix_total, vert_pix_total, visarea, refresh);
+ rectangle visarea(0, max_visible_x, 0, max_visible_y);
+ screen().configure(horiz_pix_total, vert_pix_total, visarea, (m_refresh_hack ? screen().frame_period() : refresh).as_attoseconds());
int hrtc_on_pos = CHARACTERS_PER_ROW * m_hpixels_per_column;
m_hrtc_on_timer->adjust(screen().time_until_pos(y, hrtc_on_pos), 0, screen().scan_period());
diff --git a/src/devices/video/i8275.h b/src/devices/video/i8275.h
index c9c27af099f..9f5e4196a16 100644
--- a/src/devices/video/i8275.h
+++ b/src/devices/video/i8275.h
@@ -2,30 +2,30 @@
// copyright-holders:Curt Coder
/**********************************************************************
- Intel 8275 Programmable CRT Controller emulation
+ Intel 8275/8276 CRT Controller emulation
**********************************************************************
- _____ _____
- LC3 1 |* \_/ | 40 Vcc
- LC2 2 | | 39 LA0
- LC1 3 | | 38 LA1
- LC0 4 | | 37 LTEN
- DRQ 5 | | 36 RVV
- _DACK 6 | | 35 VSP
- HRTC 7 | | 34 GPA1
- VRTC 8 | | 33 GPA0
- _RD 9 | | 32 HLGT
- _WR 10 | 8275 | 31 IRQ
- LPEN 11 | | 30 CCLK
- DB0 12 | | 29 CC6
- DB1 13 | | 28 CC5
- DB2 14 | | 27 CC4
- DB3 15 | | 26 CC3
- DB4 16 | | 25 CC2
- DB5 17 | | 24 CC1
- DB6 18 | | 23 CC0
- DB7 19 | | 22 _CS
- GND 20 |_____________| 21 A0
+ ____ ____ ____ ____
+ LC3 1 |* \_/ | 40 Vcc LC3 1 |* \_/ | 40 Vcc
+ LC2 2 | | 39 LA0 LC2 2 | | 39 NC
+ LC1 3 | | 38 LA1 LC1 3 | | 38 NC
+ LC0 4 | | 37 LTEN LC0 4 | | 37 LTEN
+ DRQ 5 | | 36 RVV BRDY 5 | | 36 RVV
+ _DACK 6 | | 35 VSP _BS 6 | | 35 VSP
+ HRTC 7 | | 34 GPA1 HRTC 7 | | 34 GPA1
+ VRTC 8 | | 33 GPA0 VRTC 8 | | 33 GPA0
+ _RD 9 | | 32 HLGT _RD 9 | | 32 HLGT
+ _WR 10 | 8275 | 31 IRQ _WR 10 | 8276 | 31 INT
+ LPEN 11 | | 30 CCLK NC 11 | | 30 CCLK
+ DB0 12 | | 29 CC6 DB0 12 | | 29 CC6
+ DB1 13 | | 28 CC5 DB1 13 | | 28 CC5
+ DB2 14 | | 27 CC4 DB2 14 | | 27 CC4
+ DB3 15 | | 26 CC3 DB3 15 | | 26 CC3
+ DB4 16 | | 25 CC2 DB4 16 | | 25 CC2
+ DB5 17 | | 24 CC1 DB5 17 | | 24 CC1
+ DB6 18 | | 23 CC0 DB6 18 | | 23 CC0
+ DB7 19 | | 22 _CS DB7 19 | | 22 _CS
+ GND 20 |___________| 21 A0 GND 20 |___________| 21 C/_P
**********************************************************************/
@@ -61,6 +61,7 @@ public:
i8275_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock);
void set_character_width(int value) { m_hpixels_per_column = value; }
+ void set_refresh_hack(bool hack) { m_refresh_hack = hack; }
template <typename... T> void set_display_callback(T &&... args) { m_display_cb = draw_character_delegate(std::forward<T>(args)...); }
void set_display_callback(draw_character_delegate callback) { m_display_cb = callback; }
template <class FunctionClass> void set_display_callback(const char *devname,
@@ -186,6 +187,7 @@ protected:
draw_character_delegate m_display_cb;
int m_hpixels_per_column;
+ bool m_refresh_hack;
bitmap_rgb32 m_bitmap;
diff --git a/src/mame/machine/imds2ioc.cpp b/src/mame/machine/imds2ioc.cpp
index 7c1fd7a7218..c5c148b7367 100644
--- a/src/mame/machine/imds2ioc.cpp
+++ b/src/mame/machine/imds2ioc.cpp
@@ -595,6 +595,7 @@ void imds2ioc_device::device_add_mconfig(machine_config &config)
// assumption that CCLK is fixed at BCLK / 14)
I8275(config, m_ioccrtc, 22853600 / 14);
m_ioccrtc->set_character_width(14);
+ m_ioccrtc->set_refresh_hack(true);
m_ioccrtc->set_display_callback(FUNC(imds2ioc_device::crtc_display_pixels), this);
m_ioccrtc->drq_wr_callback().set(m_iocdma, FUNC(i8257_device::dreq2_w));
m_ioccrtc->irq_wr_callback().set_inputline(m_ioccpu, I8085_INTR_LINE);