dvk_ksm: baud rate generator + source cleanup (#2432)

src/mame/drivers/dvk_ksm.cpp

@@ -3,22 +3,12 @@
 /***************************************************************************
 
     KSM (Kontroller Simvolnogo Monitora = Character Display Controller),
-    a single-board replacement for standalone 15IE-00-013 terminal (ie15.c)
+    a single-board replacement for standalone 15IE-00-013 terminal (ie15.c
-    in later-model DVK desktops.
+	driver in MAME) in later-model DVK desktops.
 
     MPI (Q-Bus clone) board, consumes only power from the bus.
     Interfaces with MS7004 (DEC LK201 workalike) keyboard and monochrome CRT.
 
-    Hardware revisions (XXX verify everything):
-    - 7.102.076 -- has DIP switches, SRAM at 0x2000, model name "KSM"
-    - 7.102.228 -- no DIP switches, ?? SRAM at 0x2100, model name "KSM-01"
-
-    Two sets of dumps exist:
-    - one puts SRAM at 0x2000, which is where technical manual puts it,
-      but chargen has 1 missing pixel in 'G' character.
-    - another puts SRAM at 0x2100, but has no missing pixel.
-    Merge them for now into one (SRAM at 0x2000 and no missing pixel).
-
     Emulates a VT52 without copier (ESC Z response is ESC / M), with
     Hold Screen mode and Graphics character set (but it is unique and
     mapped to a different range -- 100..137).
@@ -54,8 +44,9 @@ ksm|DVK KSM,
 
     To do:
     - verify if pixel stretching is done by hw
-    - verify details of hw revisions (memory map, DIP presence...)
+    - verify details of hw revisions.  known ones:
-    - baud rate selection
+      - decimal 7.102.076 -- has DIP switches, model name "KSM".
+      - decimal 7.102.228 -- no DIP switches, model name "KSM-01" -- no dump.
 
 ****************************************************************************/
 
@@ -77,13 +68,14 @@ ksm|DVK KSM,
 #define KSM_DISP_HORZ  800
 #define KSM_HORZ_START 200
 
-#define KSM_TOTAL_VERT 28*11
+#define KSM_TOTAL_VERT (28 * 11)
-#define KSM_DISP_VERT  25*11
+#define KSM_DISP_VERT  (25 * 11)
-#define KSM_VERT_START 2*11
+#define KSM_VERT_START (2 * 11)
 
 #define KSM_STATUSLINE_TOTAL 11
 #define KSM_STATUSLINE_VRAM 0xF8B0
 
+
 #define VERBOSE_DBG 0       /* general debug messages */
 
 #define DBG_LOG(N,M,A) \
@@ -119,8 +111,13 @@ public:
 	virtual void video_start() override;
 	uint32_t screen_update(screen_device &screen, bitmap_ind16 &bitmap, const rectangle &cliprect);
 
+	virtual void device_timer(emu_timer &timer, device_timer_id id, int param, void *ptr) override;
+
 	DECLARE_WRITE_LINE_MEMBER(write_keyboard_clock);
-	DECLARE_WRITE_LINE_MEMBER(write_line_clock);
+
+	DECLARE_WRITE_LINE_MEMBER(write_brga);
+	DECLARE_WRITE_LINE_MEMBER(write_brgb);
+	DECLARE_WRITE_LINE_MEMBER(write_brgc);
 
 	DECLARE_WRITE8_MEMBER(ksm_ppi_porta_w);
 	DECLARE_WRITE8_MEMBER(ksm_ppi_portc_w);
@@ -136,6 +133,17 @@ private:
 		uint16_t ptr;
 	} m_video;
 
+	enum
+	{
+		TIMER_ID_BRG = 0
+	};
+
+	bool brg_state;
+	int brga, brgb, brgc;
+	emu_timer *m_brg = nullptr;
+
+	void update_brg(bool a, bool b, int c);
+
 	required_shared_ptr<uint8_t> m_p_videoram;
 	required_device<cpu_device> m_maincpu;
 	required_device<pic8259_device> m_pic8259;
@@ -206,15 +214,31 @@ static INPUT_PORTS_START( ksm )
 	PORT_DIPSETTING(0x0E, "75")
 INPUT_PORTS_END
 
+void ksm_state::device_timer(emu_timer &timer, device_timer_id id, int param, void *ptr)
+{
+	if (id == TIMER_ID_BRG)
+	{
+		brg_state = !brg_state;
+		m_i8251line->write_txc(brg_state);
+		m_i8251line->write_rxc(brg_state);
+	}
+}
+
 void ksm_state::machine_reset()
 {
 	memset(&m_video, 0, sizeof(m_video));
+	brga = 0;
+	brgb = 0;
+	brgc = 0;
+	brg_state = 0;
 }
 
 void ksm_state::video_start()
 {
 	m_tmpclip = rectangle(0, KSM_DISP_HORZ - 1, 0, KSM_DISP_VERT - 1);
 	m_tmpbmp.allocate(KSM_DISP_HORZ, KSM_DISP_VERT);
+
+	m_brg = timer_alloc(TIMER_ID_BRG);
 }
 
 WRITE8_MEMBER(ksm_state::ksm_ppi_porta_w)
@@ -225,7 +249,11 @@ WRITE8_MEMBER(ksm_state::ksm_ppi_porta_w)
 
 WRITE8_MEMBER(ksm_state::ksm_ppi_portc_w)
 {
-	DBG_LOG(1, "PPI port C", ("blink %d speed %d\n", BIT(data, 7), ((data >> 4) & 7)));
+	brgc = (data >> 5) & 3;
+
+	DBG_LOG(1, "PPI port C", ("raw %02x blink %d speed %d\n", data, BIT(data, 7), brgc));
+
+	update_brg(brga, brgb, brgc);
 }
 
 WRITE_LINE_MEMBER(ksm_state::write_keyboard_clock)
@@ -234,10 +262,50 @@ WRITE_LINE_MEMBER(ksm_state::write_keyboard_clock)
 	m_i8251kbd->write_rxc(state);
 }
 
-WRITE_LINE_MEMBER(ksm_state::write_line_clock)
+WRITE_LINE_MEMBER(ksm_state::write_brga)
 {
-	m_i8251line->write_txc(state);
+	brga = state;
-	m_i8251line->write_rxc(state);
+	update_brg(brga, brgb, brgc);
+}
+
+WRITE_LINE_MEMBER(ksm_state::write_brgb)
+{
+	brgb = state;
+	update_brg(brga, brgb, brgc);
+}
+
+void ksm_state::update_brg(bool a, bool b, int c)
+{
+	DBG_LOG(2, "brg", ("%d %d %d\n", a, b, c));
+
+	if (a && b) return;
+
+	switch ((a << 3) + (b << 2) + c)
+	{
+	case 0xa:
+		m_brg->adjust(attotime::from_hz(9600*16*2), 0, attotime::from_hz(9600*16*2));
+		break;
+
+	case 0x8:
+		m_brg->adjust(attotime::from_hz(4800*16*2), 0, attotime::from_hz(4800*16*2));
+		break;
+
+	case 0x4:
+		m_brg->adjust(attotime::from_hz(2400*16*2), 0, attotime::from_hz(2400*16*2));
+		break;
+
+	case 0x5:
+		m_brg->adjust(attotime::from_hz(1200*16*2), 0, attotime::from_hz(1200*16*2));
+		break;
+
+	case 0x6:
+		m_brg->adjust(attotime::from_hz(600*16*2), 0, attotime::from_hz(600*16*2));
+		break;
+
+	case 0x7:
+		m_brg->adjust(attotime::from_hz(300*16*2), 0, attotime::from_hz(300*16*2));
+		break;
+	}
 }
 
 /*
@@ -362,13 +430,14 @@ static MACHINE_CONFIG_START( ksm )
 
 	MCFG_PIC8259_ADD( "pic8259", INPUTLINE("maincpu", 0), VCC, NOOP)
 
+	// D30
 	MCFG_DEVICE_ADD("ppi8255", I8255, 0)
 	MCFG_I8255_OUT_PORTA_CB(WRITE8(ksm_state, ksm_ppi_porta_w))
 	MCFG_I8255_IN_PORTB_CB(IOPORT("SA1"))
 	MCFG_I8255_IN_PORTC_CB(IOPORT("SA2"))
 	MCFG_I8255_OUT_PORTC_CB(WRITE8(ksm_state, ksm_ppi_portc_w))
 
-	// serial connection to host
+	// D42 - serial connection to host
 	MCFG_DEVICE_ADD( "i8251line", I8251, 0)
 	MCFG_I8251_TXD_HANDLER(DEVWRITELINE("rs232", rs232_port_device, write_txd))
 	MCFG_I8251_RXRDY_HANDLER(DEVWRITELINE("pic8259", pic8259_device, ir3_w))
@@ -378,13 +447,11 @@ static MACHINE_CONFIG_START( ksm )
 	MCFG_RS232_CTS_HANDLER(DEVWRITELINE("i8251line", i8251_device, write_cts))
 	MCFG_RS232_DSR_HANDLER(DEVWRITELINE("i8251line", i8251_device, write_dsr))
 
-	// XXX /RTS, /DTR, PC5 and PC6 are wired to baud rate generator.
+	// D41 - serial connection to MS7004 keyboard
-	MCFG_DEVICE_ADD("line_clock", CLOCK, 9600*16) // 8251 is set to /16 on the clock input
-	MCFG_CLOCK_SIGNAL_HANDLER(WRITELINE(ksm_state, write_line_clock))
-
-	// serial connection to MS7004 keyboard
 	MCFG_DEVICE_ADD( "i8251kbd", I8251, 0)
 	MCFG_I8251_RXRDY_HANDLER(DEVWRITELINE("pic8259", pic8259_device, ir1_w))
+	MCFG_I8251_RTS_HANDLER(WRITELINE(ksm_state, write_brga))
+	MCFG_I8251_DTR_HANDLER(WRITELINE(ksm_state, write_brgb))
 
 	MCFG_DEVICE_ADD("ms7004", MS7004, 0)
 	MCFG_MS7004_TX_HANDLER(DEVWRITELINE("i8251kbd", i8251_device, write_rxd))