diff --git a/src/device.c b/src/device.c
index 8965907..6c1af73 100644
--- a/src/device.c
+++ b/src/device.c
@@ -11,7 +11,7 @@
  *
  * **TODO**	Merge the various 'add' variants, its getting too messy.
  *
- * Version:	@(#)device.c	1.0.22	2019/04/21
+ * Version:	@(#)device.c	1.0.24	2019/05/05
  *
  * Authors:	Fred N. van Kempen, <decwiz@yahoo.com>
  *		Miran Grca, <mgrca8@gmail.com>
@@ -51,6 +51,7 @@
 #include "device.h"
 #include "machines/machine.h"
 #include "devices/sound/sound.h"
+#include "devices/video/video.h"
 #include "ui/ui.h"
 #include "plat.h"
 
@@ -392,6 +393,8 @@ device_speed_changed(void)
     }
 
     sound_speed_changed();
+
+    video_update_timing();
 }
 
 
diff --git a/src/devices/sound/snd_pas16.c b/src/devices/sound/snd_pas16.c
index 2c3239a..5744839 100644
--- a/src/devices/sound/snd_pas16.c
+++ b/src/devices/sound/snd_pas16.c
@@ -79,7 +79,7 @@
  *		FF88 - board model
  *		  3 = PAS16
  *
- * Version:	@(#)snd_pas16.c	1.0.13	2019/04/25
+ * Version:	@(#)snd_pas16.c	1.0.14	2019/05/05
  *
  * Authors:	Fred N. van Kempen, <decwiz@yahoo.com>
  *		Miran Grca, <mgrca8@gmail.com>
@@ -119,6 +119,7 @@
 #include "../../timer.h"
 #include "../../device.h"
 #include "../../plat.h"
+#include "../system/clk.h"
 #include "../system/dma.h"
 #include "../system/pic.h"
 #include "../system/pit.h"
diff --git a/src/devices/sound/snd_speaker.c b/src/devices/sound/snd_speaker.c
index 6fc5290..d81ee48 100644
--- a/src/devices/sound/snd_speaker.c
+++ b/src/devices/sound/snd_speaker.c
@@ -8,7 +8,7 @@
  *
  *		Implementation of the PC-Speaker device.
  *
- * Version:	@(#)snd_speaker.c	1.0.6	2019/02/12
+ * Version:	@(#)snd_speaker.c	1.0.7	2019/05/05
  *
  * Authors:	Fred N. van Kempen, <decwiz@yahoo.com>
  *		Miran Grca, <mgrca8@gmail.com>
@@ -43,6 +43,7 @@
 #define dbglog sound_card_log
 #include "../../emu.h"
 #include "../system/pit.h"
+#include "../system/ppi.h"
 #include "sound.h"
 #include "snd_speaker.h"
 
@@ -60,6 +61,26 @@ static int32_t	speaker_buffer[SOUNDBUFLEN];
 static int	speaker_pos;
 
 
+static void
+get_buffer(int32_t *buffer, int len, void *p)
+{
+    int32_t val;
+    int c;
+
+    speaker_update();
+        
+    if (! speaker_mute) {
+	for (c = 0; c < len * 2; c++) {
+		val = speaker_buffer[c >> 1];
+		buffer[c++] += val;
+		buffer[c] += val;
+	}
+    }
+
+    speaker_pos = 0;
+}
+
+
 void
 speaker_update(void)
 {
@@ -87,23 +108,20 @@ speaker_update(void)
 }
 
 
-static void
-get_buffer(int32_t *buffer, int len, void *p)
+void
+speaker_timer(int new_out, int old_out)
 {
-    int32_t val;
-    int c;
+    int64_t l;
 
     speaker_update();
-        
-    if (! speaker_mute) {
-	for (c = 0; c < len * 2; c++) {
-		val = speaker_buffer[c >> 1];
-		buffer[c++] += val;
-		buffer[c] += val;
-	}
-    }
 
-    speaker_pos = 0;
+    l = pit.l[2] ? pit.l[2] : 0x10000LL;
+    if (l < 25LL)
+        speaker_on = 0;
+      else
+        speaker_on = new_out;
+
+    ppispeakon = new_out;
 }
 
 
diff --git a/src/devices/sound/snd_speaker.h b/src/devices/sound/snd_speaker.h
index 3140b7d..80f7a24 100644
--- a/src/devices/sound/snd_speaker.h
+++ b/src/devices/sound/snd_speaker.h
@@ -8,7 +8,7 @@
  *
  *		Definitions for the PC-Speaker driver.
  *
- * Version:	@(#)snd_speaker.h	1.0.3	2019/02/12
+ * Version:	@(#)snd_speaker.h	1.0.4	2019/05/05
  *
  * Authors:	Fred N. van Kempen, <decwiz@yahoo.com>
  *		Miran Grca, <mgrca8@gmail.com>
@@ -51,6 +51,7 @@ extern int	speaker_val,
 
 extern void	speaker_reset(void);
 extern void	speaker_update(void);
+extern void	speaker_timer(int new_out, int old_out);
 
 
 #endif	/*SOUND_SPEAKER_H*/
diff --git a/src/devices/system/intel.c b/src/devices/system/intel.c
index ee86833..18dc0f1 100644
--- a/src/devices/system/intel.c
+++ b/src/devices/system/intel.c
@@ -8,7 +8,7 @@
  *
  *		Implementation of Intel mainboards.
  *
- * Version:	@(#)intel.c	1.0.10	2019/04/25
+ * Version:	@(#)intel.c	1.0.11	2019/05/05
  *
  * Authors:	Fred N. van Kempen, <decwiz@yahoo.com>
  *		Miran Grca, <mgrca8@gmail.com>
@@ -49,7 +49,7 @@
 #include "../../device.h"
 #include "../../plat.h"
 #include "intel.h"
-#include "pit.h"
+#include "clk.h"
 
 
 typedef struct {
diff --git a/src/devices/system/nvr_at.c b/src/devices/system/nvr_at.c
index 73f6e76..a545f8b 100644
--- a/src/devices/system/nvr_at.c
+++ b/src/devices/system/nvr_at.c
@@ -189,7 +189,7 @@
  *		including the later update (DS12887A) which implemented a
  *		"century" register to be compatible with Y2K.
  *
- * Version:	@(#)nvr_at.c	1.0.18	2019/05/03
+ * Version:	@(#)nvr_at.c	1.0.19	2019/05/05
  *
  * Authors:	Fred N. van Kempen, <decwiz@yahoo.com>
  *		Miran Grca, <mgrca8@gmail.com>
@@ -234,9 +234,9 @@
 #include "../../device.h"
 #include "../../nvr.h"
 #include "../../plat.h"
+#include "clk.h"
 #include "nmi.h"
 #include "pic.h"
-#include "pit.h"
 
 
 /* RTC registers and bit definitions. */
diff --git a/src/devices/system/pit.c b/src/devices/system/pit.c
index 1fcde8d..2f2378d 100644
--- a/src/devices/system/pit.c
+++ b/src/devices/system/pit.c
@@ -13,7 +13,7 @@
  *		B4 to 40, two writes to 43, then two reads
  *			- value _does_ change!
  *
- * Version:	@(#)pit.c	1.0.14	2019/04/25
+ * Version:	@(#)pit.c	1.0.15	2019/05/05
  *
  * Authors:	Fred N. van Kempen, <decwiz@yahoo.com>
  *		Miran Grca, <mgrca8@gmail.com>
@@ -56,32 +56,21 @@
 #ifdef USE_CASSETTE
 # include <cassette.h>
 #endif
-#include "../video/video.h"
+#include "clk.h"
 #include "nmi.h"
-#include "dma.h"
 #include "pic.h"
 #include "pit.h"
-#include "ppi.h"
 
 
 PIT	pit,
 	pit2;
 
-float	cpuclock;
-float	bus_timing;
-
-double	PITCONST;
-float	CGACONST;
-float	MDACONST;
-float	VGACONST1,
-	VGACONST2;
-float	RTCCONST;
-
 
 static void
 set_out(PIT *dev, int t, int out)
 {
-    dev->set_out_funcs[t](out, dev->out[t]);
+    if (dev->funcs[t])
+	dev->funcs[t](out, dev->out[t]);
     dev->out[t] = out;
 }
 
@@ -212,19 +201,6 @@ do_over(PIT *dev, int t)
 }
 
 
-static void
-pit_clock(PIT *dev, int t)
-{
-    if (dev->thit[t] || !dev->enabled[t]) return;
-
-    if (dev->using_timer[t]) return;
-
-    dev->count[t] -= (dev->m[t] == 3) ? 2 : 1;
-    if (dev->count[t] == 0)
-	do_over(dev, t);
-}
-
-
 static void
 timer_over(void *priv)
 {
@@ -504,13 +480,6 @@ pit_read(uint16_t addr, void *priv)
 }
 
 
-/* FIXME: should be removed. */
-static void
-null_timer(int new_out, int old_out)
-{
-}
-
-
 /* FIXME: should be moved to machine.c (default for most machines..) */
 static void
 irq0_timer(int new_out, int old_out)
@@ -523,24 +492,6 @@ irq0_timer(int new_out, int old_out)
 }
 
 
-/* FIXME: should be moved to snd_speaker.c */
-static void
-speaker_timer(int new_out, int old_out)
-{
-    int64_t l;
-
-    speaker_update();
-
-    l = pit.l[2] ? pit.l[2] : 0x10000LL;
-    if (l < 25LL)
-	speaker_on = 0;
-      else
-	speaker_on = new_out;
-
-    ppispeakon = new_out;
-}
-
-
 void
 pit_init(void)
 {
@@ -561,12 +512,10 @@ pit_init(void)
     io_sethandler(0x0040, 4,
 		  pit_read,NULL,NULL, pit_write,NULL,NULL, &pit);
 
+//FIXME: these two should be moved to the machine files!
     /* Timer0: the TOD clock. */
     pit_set_out_func(&pit, 0, irq0_timer);
 
-    /* Timer1: unused. */
-    pit_set_out_func(&pit, 1, null_timer);
-
     /* Timer2: speaker and cassette. */
     pit_set_out_func(&pit, 2, speaker_timer);
     pit.gate[2] = 0;
@@ -626,14 +575,14 @@ pit_ps2_init(void)
 void
 pit_reset(PIT *dev)
 {
-    void (*old_set_out_funcs[3])(int new_out, int old_out);
+    void (*old_funcs[3])(int new_out, int old_out);
     PIT_nr old_pit_nr[3];
     int i;
 
-    memcpy(old_set_out_funcs, dev->set_out_funcs, 3 * sizeof(void *));
+    memcpy(old_funcs, dev->funcs, 3 * sizeof(void *));
     memcpy(old_pit_nr, dev->pit_nr, 3 * sizeof(PIT_nr));
-    memset(dev, 0, sizeof(PIT));
-    memcpy(dev->set_out_funcs, old_set_out_funcs, 3 * sizeof(void *));
+    memset(dev, 0x00, sizeof(PIT));
+    memcpy(dev->funcs, old_funcs, 3 * sizeof(void *));
     memcpy(dev->pit_nr, old_pit_nr, 3 * sizeof(PIT_nr));
 
     for (i = 0; i < 3; i++) {
@@ -652,105 +601,16 @@ pit_reset(PIT *dev)
 }
 
 
-/* Set default CPU/crystal clock and xt_cpu_multi. */
 void
-pit_setclock(uint32_t freq)
+pit_clock(PIT *dev, int t)
 {
-    uint32_t speed;
+    if (dev->thit[t] || !dev->enabled[t]) return;
 
-    if (cpu_get_type() >= CPU_286) {
-	/* For 286 and up, this is easy. */
-	cpuclock = (float)freq;
-	PITCONST = cpuclock / 1193182.0;
-	CGACONST = (float) (cpuclock  / (19687503.0 / 11.0));
-	xt_cpu_multi = 1;
-    } else {
-	/* Not so much for XT-class systems. */
-	cpuclock = 14318184.0;
-       	PITCONST = 12.0;
-        CGACONST = 8.0;
-	xt_cpu_multi = 3;
+    if (dev->using_timer[t]) return;
 
-	/* Get selected CPU's (max) clock rate. */
-	speed = cpu_get_speed();
-
-	switch (speed) {
-		case 7159092:	/* 7.16 MHz */
-			if (cpu_get_flags() & CPU_ALTERNATE_XTAL) {
-				cpuclock = 28636368.0;
-				xt_cpu_multi = 4;
-			} else
-				xt_cpu_multi = 2;
-			break;
-
-		case 8000000:	/* 8 MHz */
-		case 9545456:	/* 9.54 MHz */
-		case 10000000:	/* 10 MHz */
-		case 12000000:	/* 12 MHz */
-		case 16000000:	/* 16 MHz */
-			cpuclock = ((float)speed * xt_cpu_multi);
-			break;
-
-		default:
-			if (cpu_get_flags() & CPU_ALTERNATE_XTAL) {
-				cpuclock = 28636368.0;
-				xt_cpu_multi = 6;
-			}
-			break;
-	}
-
-	if (cpuclock == 28636368.0) {
-        	PITCONST = 24.0;
-	        CGACONST = 16.0;
-	} else if (cpuclock != 14318184.0) {
-		PITCONST = cpuclock / 1193182.0;
-		CGACONST = (float) (cpuclock / (19687503.0 / 11.0));
-	}
-   }
-
-    xt_cpu_multi <<= TIMER_SHIFT;
-
-    MDACONST = (float) (cpuclock / 2032125.0);
-    VGACONST1 = (float) (cpuclock / 25175000.0);
-    VGACONST2 = (float) (cpuclock / 28322000.0);
-    RTCCONST = (float) (cpuclock / 32768.0);
-
-    TIMER_USEC = (int64_t)((cpuclock / 1000000.0f) * (float)(1 << TIMER_SHIFT));
-
-    bus_timing = (float) (cpuclock / (double)cpu_busspeed);
-
-INFO("PIT: cpu=%.2f xt=%d PIT=%.2f RTC=%.2f CGA=%.2f MDA=%.2f TMR=%" PRIu64 "\n",
-	cpuclock, xt_cpu_multi, (float)PITCONST, RTCCONST, CGACONST, MDACONST,
-	TIMER_USEC);
-
-    video_update_timing();
-
-    device_speed_changed();
-}
-
-
-void
-clearpit(void)
-{
-    pit.c[0] = (pit.l[0] << 2);
-}
-
-
-int
-pit_get_timer_0(void)
-{
-    int r = (int)((pit.c[0] + ((1LL << TIMER_SHIFT) - 1)) / PITCONST) >> TIMER_SHIFT;
-
-    if (pit.m[0] == 2)
-	r++;
-    if (r < 0)
-	r = 0;
-    if (r > 0x10000)
-	r = 0x10000;
-    if (pit.m[0] == 3)
-	r <<= 1;
-
-    return r;
+    dev->count[t] -= (dev->m[t] == 3) ? 2 : 1;
+    if (dev->count[t] == 0)
+	do_over(dev, t);
 }
 
 
@@ -825,37 +685,5 @@ pit_set_using_timer(PIT *dev, int t, int using_timer)
 void
 pit_set_out_func(PIT *dev, int t, void (*func)(int new_out, int old_out))
 {
-    dev->set_out_funcs[t] = func;
-}
-
-
-/* FIXME: should be moved to m_pcjr.c */
-void
-pit_irq0_timer_pcjr(int new_out, int old_out)
-{
-    if (new_out && !old_out) {
-	picint(1);
-	pit_clock(&pit, 1);
-    }
-
-    if (! new_out)
-	picintc(1);
-}
-
-
-/* FIXME: should be moved to m_xt.c */
-void
-pit_refresh_timer_xt(int new_out, int old_out)
-{
-    if (new_out && !old_out)
-	dma_channel_read(0);
-}
-
-
-/* FIXME: should be moved to m_at.c */
-void
-pit_refresh_timer_at(int new_out, int old_out)
-{
-    if (new_out && !old_out)
-	ppi.pb ^= 0x10;
+    dev->funcs[t] = func;
 }
diff --git a/src/devices/system/pit.h b/src/devices/system/pit.h
index e826176..517fe2f 100644
--- a/src/devices/system/pit.h
+++ b/src/devices/system/pit.h
@@ -8,7 +8,7 @@
  *
  *		Definitions for Intel 8253 timer module.
  *
- * Version:	@(#)pit.h	1.0.6	2019/02/15
+ * Version:	@(#)pit.h	1.0.7	2019/05/05
  *
  * Authors:	Fred N. van Kempen, <decwiz@yahoo.com>
  *		Miran Grca, <mgrca8@gmail.com>
@@ -74,21 +74,13 @@ typedef struct PIT {
 
     PIT_nr	pit_nr[3];
 
-    void	(*set_out_funcs[3])(int new_out, int old_out);
+    void	(*funcs[3])(int new_out, int old_out);
 } PIT;
 
 
 extern PIT	pit,
 		pit2;
 
-extern double	PITCONST;
-
-extern float	CGACONST,
-		MDACONST,
-		VGACONST1,
-		VGACONST2,
-		RTCCONST;
-
 
 extern void	pit_init(void);
 extern void	pit_ps2_init(void);
@@ -96,13 +88,7 @@ extern void	pit_reset(PIT *pit);
 extern void	pit_set_gate(PIT *pit, int channel, int gate);
 extern void	pit_set_using_timer(PIT *pit, int t, int using_timer);
 extern void	pit_set_out_func(PIT *pit, int t, void (*func)(int new_out, int old_out));
-
-extern float    pit_timer0_freq(void);
-extern void	pit_irq0_timer_pcjr(int new_out, int old_out);
-extern void	pit_refresh_timer_xt(int new_out, int old_out);
-extern void	pit_refresh_timer_at(int new_out, int old_out);
-
-extern void	pit_setclock(uint32_t freq);
+extern void	pit_clock(PIT *dev, int t);
 
 
 #endif	/*EMU_PIT_H*/
diff --git a/src/devices/video/vid_cga.c b/src/devices/video/vid_cga.c
index 6c3bf1e..9308e57 100644
--- a/src/devices/video/vid_cga.c
+++ b/src/devices/video/vid_cga.c
@@ -8,7 +8,7 @@
  *
  *		Emulation of the old and new IBM CGA graphics cards.
  *
- * Version:	@(#)vid_cga.c	1.0.17	2019/04/25
+ * Version:	@(#)vid_cga.c	1.0.18	2019/05/05
  *
  * Authors:	Fred N. van Kempen, <decwiz@yahoo.com>
  *		Miran Grca, <mgrca8@gmail.com>
@@ -50,7 +50,7 @@
 #include "../../timer.h"
 #include "../../device.h"
 #include "../../plat.h"
-#include "../system/pit.h"
+#include "../system/clk.h"
 #include "video.h"
 #include "vid_cga.h"
 #include "vid_cga_comp.h"
diff --git a/src/devices/video/vid_cga_compaq.c b/src/devices/video/vid_cga_compaq.c
index cb63eec..4e8941c 100644
--- a/src/devices/video/vid_cga_compaq.c
+++ b/src/devices/video/vid_cga_compaq.c
@@ -8,7 +8,7 @@
  *
  *		Implementation of CGA used by Compaq PC's.
  *
- * Version:	@(#)vid_cga_compaq.c	1.0.10	2019/04/25
+ * Version:	@(#)vid_cga_compaq.c	1.0.11	2019/05/05
  *
  * Authors:	Fred N. van Kempen, <decwiz@yahoo.com>
  *		Miran Grca, <mgrca8@gmail.com>
@@ -49,7 +49,7 @@
 #include "../../timer.h"
 #include "../../device.h"
 #include "../../plat.h"
-#include "../system/pit.h"
+#include "../system/clk.h"
 #include "video.h"
 #include "vid_cga.h"
 #include "vid_cga_comp.h"
diff --git a/src/devices/video/vid_colorplus.c b/src/devices/video/vid_colorplus.c
index bf75bbe..bab399e 100644
--- a/src/devices/video/vid_colorplus.c
+++ b/src/devices/video/vid_colorplus.c
@@ -8,7 +8,7 @@
  *
  *		Plantronics ColorPlus emulation.
  *
- * Version:	@(#)vid_colorplus.c	1.0.15	2019/05/03
+ * Version:	@(#)vid_colorplus.c	1.0.16	2019/05/05
  *
  * Authors:	Fred N. van Kempen, <decwiz@yahoo.com>
  *		Miran Grca, <mgrca8@gmail.com>
@@ -50,7 +50,7 @@
 #include "../../timer.h"
 #include "../../device.h"
 #include "../../plat.h"
-#include "../system/pit.h"
+#include "../system/clk.h"
 #include "../ports/parallel.h"
 #include "video.h"
 #include "vid_cga.h"
diff --git a/src/devices/video/vid_ega.c b/src/devices/video/vid_ega.c
index c939c13..31726dd 100644
--- a/src/devices/video/vid_ega.c
+++ b/src/devices/video/vid_ega.c
@@ -9,7 +9,7 @@
  *		Emulation of the EGA, Chips & Technologies SuperEGA, and
  *		AX JEGA graphics cards.
  *
- * Version:	@(#)vid_ega.c	1.0.18	2019/05/05
+ * Version:	@(#)vid_ega.c	1.0.19	2019/05/05
  *
  * Authors:	Fred N. van Kempen, <decwiz@yahoo.com>
  *		Miran Grca, <mgrca8@gmail.com>
@@ -50,7 +50,7 @@
 #include "../../timer.h"
 #include "../../device.h"
 #include "../../plat.h"
-#include "../system/pit.h"
+#include "../system/clk.h"
 #include "video.h"
 #include "vid_ega.h"
 #include "vid_ega_render.h"
diff --git a/src/devices/video/vid_genius.c b/src/devices/video/vid_genius.c
index f46189b..00b53c3 100644
--- a/src/devices/video/vid_genius.c
+++ b/src/devices/video/vid_genius.c
@@ -63,7 +63,7 @@
  *		reducing the height of characters so they fit in an 8x12 cell
  *		if necessary.
  *
- * Version:	@(#)vid_genius.c	1.0.14	2019/05/05
+ * Version:	@(#)vid_genius.c	1.0.15	2019/05/05
  *
  * Authors:	Fred N. van Kempen, <decwiz@yahoo.com>
  *		Miran Grca, <mgrca8@gmail.com>
@@ -103,7 +103,7 @@
 #include "../../timer.h"
 #include "../../device.h"
 #include "../../plat.h"
-#include "../system/pit.h"
+#include "../system/clk.h"
 #include "video.h"
 
 
diff --git a/src/devices/video/vid_hercules.c b/src/devices/video/vid_hercules.c
index c0026b7..ff63a69 100644
--- a/src/devices/video/vid_hercules.c
+++ b/src/devices/video/vid_hercules.c
@@ -8,7 +8,7 @@
  *
  *		Hercules emulation.
  *
- * Version:	@(#)vid_hercules.c	1.0.19	2019/05/03
+ * Version:	@(#)vid_hercules.c	1.0.20	2019/05/05
  *
  * Authors:	Fred N. van Kempen, <decwiz@yahoo.com>
  *		Miran Grca, <mgrca8@gmail.com>
@@ -50,7 +50,7 @@
 #include "../../timer.h"
 #include "../../device.h"
 #include "../../plat.h"
-#include "../system/pit.h"
+#include "../system/clk.h"
 #include "../ports/parallel.h"
 #include "video.h"
 
diff --git a/src/devices/video/vid_herculesplus.c b/src/devices/video/vid_herculesplus.c
index 145163c..4c13cd9 100644
--- a/src/devices/video/vid_herculesplus.c
+++ b/src/devices/video/vid_herculesplus.c
@@ -8,7 +8,7 @@
  *
  *		Hercules Plus emulation.
  *
- * Version:	@(#)vid_hercules_plus.c	1.0.20	2019/05/03
+ * Version:	@(#)vid_hercules_plus.c	1.0.21	2019/05/05
  *
  * Authors:	Fred N. van Kempen, <decwiz@yahoo.com>
  *		Miran Grca, <mgrca8@gmail.com>
@@ -49,7 +49,7 @@
 #include "../../timer.h"
 #include "../../device.h"
 #include "../../plat.h"
-#include "../system/pit.h"
+#include "../system/clk.h"
 #include "../ports/parallel.h"
 #include "video.h"
 
diff --git a/src/devices/video/vid_incolor.c b/src/devices/video/vid_incolor.c
index 7063edb..fda81de 100644
--- a/src/devices/video/vid_incolor.c
+++ b/src/devices/video/vid_incolor.c
@@ -8,7 +8,7 @@
  *
  *		Hercules InColor emulation.
  *
- * Version:	@(#)vid_incolor.c	1.0.18	2019/05/03
+ * Version:	@(#)vid_incolor.c	1.0.19	2019/05/05
  *
  * Authors:	Fred N. van Kempen, <decwiz@yahoo.com>
  *		Miran Grca, <mgrca8@gmail.com>
@@ -49,7 +49,7 @@
 #include "../../timer.h"
 #include "../../device.h"
 #include "../../plat.h"
-#include "../system/pit.h"
+#include "../system/clk.h"
 #include "../ports/parallel.h"
 #include "video.h"
 
diff --git a/src/devices/video/vid_mda.c b/src/devices/video/vid_mda.c
index 90fc75c..5f097f9 100644
--- a/src/devices/video/vid_mda.c
+++ b/src/devices/video/vid_mda.c
@@ -8,7 +8,7 @@
  *
  *		MDA emulation.
  *
- * Version:	@(#)vid_mda.c	1.0.15	2019/05/03
+ * Version:	@(#)vid_mda.c	1.0.16	2019/05/05
  *
  * Authors:	Fred N. van Kempen, <decwiz@yahoo.com>
  *		Miran Grca, <mgrca8@gmail.com>
@@ -49,7 +49,7 @@
 #include "../../timer.h"
 #include "../../device.h"
 #include "../../plat.h"
-#include "../system/pit.h"
+#include "../system/clk.h"
 #include "../ports/parallel.h"
 #include "video.h"
 #include "vid_mda.h"
diff --git a/src/devices/video/vid_sigma.c b/src/devices/video/vid_sigma.c
index c98a707..75ec55d 100644
--- a/src/devices/video/vid_sigma.c
+++ b/src/devices/video/vid_sigma.c
@@ -41,7 +41,7 @@
  *		even-numbered columns, so the top bit of the control register
  *		at 0x2D9 is used to adjust the position.
  *
- * Version:	@(#)vid_sigma.c	1.0.8	2019/05/05
+ * Version:	@(#)vid_sigma.c	1.0.9	2019/05/05
  *
  * Authors:	Fred N. van Kempen, <decwiz@yahoo.com>
  *		Miran Grca, <mgrca8@gmail.com>
@@ -82,8 +82,8 @@
 #include "../../timer.h"
 #include "../../device.h"
 #include "../../plat.h"
+#include "../system/clk.h"
 #include "../system/nmi.h"
-#include "../system/pit.h"
 #include "video.h"
 #include "vid_cga.h"
 
diff --git a/src/devices/video/vid_svga.c b/src/devices/video/vid_svga.c
index da233b9..816e018 100644
--- a/src/devices/video/vid_svga.c
+++ b/src/devices/video/vid_svga.c
@@ -11,7 +11,7 @@
  *		This is intended to be used by another SVGA driver,
  *		and not as a card in it's own right.
  *
- * Version:	@(#)vid_svga.c	1.0.21	2019/05/03
+ * Version:	@(#)vid_svga.c	1.0.22	2019/05/05
  *
  * Authors:	Fred N. van Kempen, <decwiz@yahoo.com>
  *		Miran Grca, <mgrca8@gmail.com>
@@ -52,7 +52,7 @@
 #include "../../mem.h"
 #include "../../rom.h"
 #include "../../timer.h"
-#include "../system/pit.h"
+#include "../system/clk.h"
 #include "video.h"
 #include "vid_svga.h"
 #include "vid_svga_render.h"
diff --git a/src/devices/video/vid_wy700.c b/src/devices/video/vid_wy700.c
index 1eb89e6..28c502c 100644
--- a/src/devices/video/vid_wy700.c
+++ b/src/devices/video/vid_wy700.c
@@ -53,7 +53,7 @@
  *		What doesn't work, is untested or not well understood:
  *		  - Cursor detach (commands 4 and 5)
  *
- * Version:	@(#)vid_wy700.c	1.0.11	2019/05/05
+ * Version:	@(#)vid_wy700.c	1.0.12	2019/05/05
  *
  * Authors:	Fred N. van Kempen, <decwiz@yahoo.com>
  *		Miran Grca, <mgrca8@gmail.com>
@@ -93,7 +93,7 @@
 #include "../../timer.h"
 #include "../../device.h"
 #include "../../plat.h"
-#include "../system/pit.h"
+#include "../system/clk.h"
 #include "video.h"
 
 
diff --git a/src/machines/m_amstrad_vid.c b/src/machines/m_amstrad_vid.c
index b393ca4..a837c71 100644
--- a/src/machines/m_amstrad_vid.c
+++ b/src/machines/m_amstrad_vid.c
@@ -66,8 +66,8 @@
 #include "../rom.h"
 #include "../timer.h"
 #include "../device.h"
+#include "../devices/system/clk.h"
 #include "../devices/system/nmi.h"
-#include "../devices/system/pit.h"
 #include "../devices/video/video.h"
 #include "../devices/video/vid_cga.h"
 #include "../devices/video/vid_mda.h"
diff --git a/src/machines/m_at.c b/src/machines/m_at.c
index a768209..b1b05cb 100644
--- a/src/machines/m_at.c
+++ b/src/machines/m_at.c
@@ -8,7 +8,7 @@
  *
  *		Standard PC/AT implementation.
  *
- * Version:	@(#)m_at.c	1.0.13	2019/04/11
+ * Version:	@(#)m_at.c	1.0.14	2019/05/05
  *
  * Authors:	Fred N. van Kempen, <decwiz@yahoo.com>
  *		Miran Grca, <mgrca8@gmail.com>
@@ -47,6 +47,7 @@
 #include "../nvr.h"
 #include "../devices/system/pic.h"
 #include "../devices/system/pit.h"
+#include "../devices/system/ppi.h"
 #include "../devices/system/dma.h"
 #include "../devices/input/keyboard.h"
 #include "../devices/floppy/fdd.h"
@@ -60,7 +61,8 @@ m_at_common_init(void)
 {
     machine_common_init();
 
-    pit_set_out_func(&pit, 1, pit_refresh_timer_at);
+    pit_set_out_func(&pit, 1, m_at_refresh_timer);
+
     pic2_init();
     dma16_init();
 
@@ -175,3 +177,12 @@ const device_t m_xt286 = {
     &xt286_info,
     NULL
 };
+
+
+/* Emulate a DRAM refresh cycle. */
+void
+m_at_refresh_timer(int new_out, int old_out)
+{
+    if (new_out && !old_out)
+        ppi.pb ^= 0x10;
+}
diff --git a/src/machines/m_compaq.c b/src/machines/m_compaq.c
index 901089e..cc93d5c 100644
--- a/src/machines/m_compaq.c
+++ b/src/machines/m_compaq.c
@@ -14,7 +14,7 @@
  *		(which is in m_compaq_vid.c), the Portable 3 needs the
  *		Plasma driver, there are some ROM issues, etc.
  *
- * Version:	@(#)m_compaq.c	1.0.12	2019/05/03
+ * Version:	@(#)m_compaq.c	1.0.13	2019/05/05
  *
  * Authors:	Fred N. van Kempen, <decwiz@yahoo.com>
  *		Miran Grca, <mgrca8@gmail.com>
@@ -173,7 +173,9 @@ cpq_init(const device_t *info, void *arg)
 	case 0:		/* Portable */
 		machine_common_init();
 		nmi_init();
-		pit_set_out_func(&pit, 1, pit_refresh_timer_xt);
+
+		/* Set up our DRAM refresh timer. */
+		pit_set_out_func(&pit, 1, m_xt_refresh_timer);
 
 		device_add(&keyboard_xt_device);
 		parallel_setup(0, 0x03bc);
diff --git a/src/machines/m_europc.c b/src/machines/m_europc.c
index 6b8f1ba..683f3c4 100644
--- a/src/machines/m_europc.c
+++ b/src/machines/m_europc.c
@@ -69,7 +69,7 @@
  * FIXME:	Find a new way to handle the switching of color/mono on
  *		external cards. New video_get_type(int card) function?
  *
- * Version:	@(#)m_europc.c	1.0.24	2019/05/03
+ * Version:	@(#)m_europc.c	1.0.25	2019/05/05
  *
  * Author:	Fred N. van Kempen, <decwiz@yahoo.com>
  *
@@ -724,7 +724,8 @@ europc_init(const device_t *info, void *arg)
 
     nmi_init();
 
-    pit_set_out_func(&pit, 1, pit_refresh_timer_xt);
+    /* Set up our DRAM refresh timer. */
+    pit_set_out_func(&pit, 1, m_xt_refresh_timer);
 
     /*
      * Allocate the system's I/O handlers.
diff --git a/src/machines/m_laserxt.c b/src/machines/m_laserxt.c
index 99b8dfb..c0cd67d 100644
--- a/src/machines/m_laserxt.c
+++ b/src/machines/m_laserxt.c
@@ -8,7 +8,7 @@
  *
  *		Emulation of the Laser XT series of machines.
  *
- * Version:	@(#)m_laserxt.c	1.0.11	2019/04/20
+ * Version:	@(#)m_laserxt.c	1.0.12	2019/05/05
  *
  * Authors:	Fred N. van Kempen, <decwiz@yahoo.com>
  *		Miran Grca, <mgrca8@gmail.com>
@@ -187,7 +187,8 @@ laser_init(const device_t *info, void *arg)
 
     nmi_init();
 
-    pit_set_out_func(&pit, 1, pit_refresh_timer_xt);
+    /* Set up our DRAM refresh timer. */
+    pit_set_out_func(&pit, 1, m_xt_refresh_timer);
 
     switch(dev->type) {
 	case 0:		/* Laser XT */
diff --git a/src/machines/m_olim24_vid.c b/src/machines/m_olim24_vid.c
index fa70776..2da600a 100644
--- a/src/machines/m_olim24_vid.c
+++ b/src/machines/m_olim24_vid.c
@@ -8,7 +8,7 @@
  *
  *		Emulation of the Olivetti M24 built-in video controller.
  *
- * Version:	@(#)m_olim24_vid.c	1.0.3	2019/04/25
+ * Version:	@(#)m_olim24_vid.c	1.0.4	2019/05/05
  *
  * Authors:	Fred N. van Kempen, <decwiz@yahoo.com>
  *		Miran Grca, <mgrca8@gmail.com>
@@ -48,7 +48,7 @@
 #include "../mem.h"
 #include "../timer.h"
 #include "../device.h"
-#include "../devices/system/pit.h"
+#include "../devices/system/clk.h"
 #include "../devices/video/video.h"
 #include "../devices/video/vid_cga.h"
 #include "machine.h"
diff --git a/src/machines/m_pcjr.c b/src/machines/m_pcjr.c
index 17c827b..db6d892 100644
--- a/src/machines/m_pcjr.c
+++ b/src/machines/m_pcjr.c
@@ -8,7 +8,7 @@
  *
  *		Emulation of the IBM PCjr.
  *
- * Version:	@(#)m_pcjr.c	1.0.20	2019/05/03
+ * Version:	@(#)m_pcjr.c	1.0.21	2019/05/05
  *
  * Authors:	Fred N. van Kempen, <decwiz@yahoo.com>
  *		Miran Grca, <mgrca8@gmail.com>
@@ -49,6 +49,7 @@
 #include "../mem.h"
 #include "../timer.h"
 #include "../device.h"
+#include "../devices/system/clk.h"
 #include "../devices/system/nmi.h"
 #include "../devices/system/pic.h"
 #include "../devices/system/pit.h"
@@ -724,6 +725,19 @@ kbd_adddata_ex(uint16_t val)
 }
 
 
+static void
+irq0_timer(int new_out, int old_out)
+{
+    if (new_out && !old_out) {
+	picint(1);
+	pit_clock(&pit, 1);
+    }
+
+    if (! new_out)
+	picintc(1);
+}
+
+
 static void
 pcjr_close(void *priv)
 {
@@ -765,13 +779,7 @@ pcjr_init(const device_t *info, UNUSED(void *arg))
     pic_init();
 
     pit_init();
-    pit_set_out_func(&pit, 0, pit_irq0_timer_pcjr);
-
-#if 0
-    // FIXME: already done in machine_reset()
-    (void)cpu_set();
-    pc_set_speed();
-#endif
+    pit_set_out_func(&pit, 0, irq0_timer);
 
     nmi_mask = 0x80;
 
diff --git a/src/machines/m_ps1.c b/src/machines/m_ps1.c
index 3387133..d511751 100644
--- a/src/machines/m_ps1.c
+++ b/src/machines/m_ps1.c
@@ -22,7 +22,7 @@
  *		The reserved 384K is remapped to the top of extended memory.
  *		If this is not done then you get an error on startup.
  *
- * Version:	@(#)m_ps1.c	1.0.27	2019/05/03
+ * Version:	@(#)m_ps1.c	1.0.28	2019/05/05
  *
  * Authors:	Fred N. van Kempen, <decwiz@yahoo.com>
  *		Miran Grca, <mgrca8@gmail.com>
@@ -593,7 +593,8 @@ ps1_init(const device_t *info, void *arg)
 
     mem_remap_top(384);
 
-    pit_set_out_func(&pit, 1, pit_refresh_timer_at);
+    /* Set up our DRAM refresh timer. */
+    pit_set_out_func(&pit, 1, m_at_refresh_timer);
 
     dma16_init();
     pic2_init();
diff --git a/src/machines/m_ps2_isa.c b/src/machines/m_ps2_isa.c
index c9b72dc..d463612 100644
--- a/src/machines/m_ps2_isa.c
+++ b/src/machines/m_ps2_isa.c
@@ -8,7 +8,7 @@
  *
  *		Implementation of ISA-based PS/2 machines.
  *
- * Version:	@(#)m_ps2_isa.c	1.0.18	2019/04/27
+ * Version:	@(#)m_ps2_isa.c	1.0.19	2019/05/05
  *
  * Authors:	Fred N. van Kempen, <decwiz@yahoo.com>
  *		Miran Grca, <mgrca8@gmail.com>
@@ -237,7 +237,9 @@ ps2_init(const device_t *info, void *arg)
 
     machine_common_init();
 
-    pit_set_out_func(&pit, 1, pit_refresh_timer_at);
+    /* Set up our DRAM refresh timer. */
+    pit_set_out_func(&pit, 1, m_at_refresh_timer);
+
     dma16_init();
     pic2_init();
 
diff --git a/src/machines/m_tandy1000_vid.c b/src/machines/m_tandy1000_vid.c
index a8750c9..402cf7a 100644
--- a/src/machines/m_tandy1000_vid.c
+++ b/src/machines/m_tandy1000_vid.c
@@ -49,7 +49,7 @@
 #include "../timer.h"
 #include "../nvr.h"
 #include "../device.h"
-#include "../devices/system/pit.h"
+#include "../devices/system/clk.h"
 #include "../devices/video/video.h"
 #include "../devices/video/vid_cga.h"
 #include "../devices/video/vid_cga_comp.h"
diff --git a/src/machines/m_tosh1x00.c b/src/machines/m_tosh1x00.c
index 864bf90..9c21f60 100644
--- a/src/machines/m_tosh1x00.c
+++ b/src/machines/m_tosh1x00.c
@@ -96,7 +96,7 @@
  *
  * FIXME:	The ROM drive should be re-done using the "option file".
  *
- * Version:	@(#)m_tosh1x00.c	1.0.21	2019/05/05
+ * Version:	@(#)m_tosh1x00.c	1.0.22	2019/05/05
  *
  * Authors:	Fred N. van Kempen, <decwiz@yahoo.com>
  *		Miran Grca, <mgrca8@gmail.com>
@@ -1022,7 +1022,8 @@ t1000_init(const device_t *info, void *arg)
 
     machine_common_init();
 
-    pit_set_out_func(&pit, 1, pit_refresh_timer_xt);
+    /* Set up our DRAM refresh timer. */
+    pit_set_out_func(&pit, 1, m_xt_refresh_timer);
 
     nmi_init();
 
diff --git a/src/machines/m_xt.c b/src/machines/m_xt.c
index cbe0503..7848fab 100644
--- a/src/machines/m_xt.c
+++ b/src/machines/m_xt.c
@@ -8,7 +8,7 @@
  *
  *		Implementation of standard IBM PC/XT class machine.
  *
- * Version:	@(#)m_xt.c	1.0.17	2019/04/13
+ * Version:	@(#)m_xt.c	1.0.18	2019/05/05
  *
  * Authors:	Fred N. van Kempen, <decwiz@yahoo.com>
  *		Miran Grca, <mgrca8@gmail.com>
@@ -46,6 +46,7 @@
 #include "../mem.h"
 #include "../device.h"
 #include "../devices/system/nmi.h"
+#include "../devices/system/dma.h"
 #include "../devices/system/pit.h"
 #include "../devices/input/keyboard.h"
 #include "../devices/ports/parallel.h"
@@ -87,7 +88,8 @@ xt_common_init(const device_t *info, void *arg)
 
     nmi_init();
 
-    pit_set_out_func(&pit, 1, pit_refresh_timer_xt);
+    /* Set up the DRAM refresh timer. */
+    pit_set_out_func(&pit, 1, m_xt_refresh_timer);
 
     switch(dev->type) {
 	case 0:		/* PC, 1981 */
@@ -351,3 +353,12 @@ const device_t m_xt_juko = {
     &juko_info,
     xt_config
 };
+
+
+/* Start a DRAM refresh cycle by issuing a DMA read. */
+void
+m_xt_refresh_timer(int new_out, int old_out)
+{
+    if (new_out && !old_out)
+        dma_channel_read(0);
+}
diff --git a/src/machines/m_zenith.c b/src/machines/m_zenith.c
index 8b84978..cf5b0da 100644
--- a/src/machines/m_zenith.c
+++ b/src/machines/m_zenith.c
@@ -25,7 +25,7 @@
  *		to be done on implementing other parts of the Yamaha V6355
  *		chip that implements the video controller.
  *
- * Version:	@(#)m_zenith.c	1.0.6	2019/05/03
+ * Version:	@(#)m_zenith.c	1.0.7	2019/05/05
  *
  * Authors:	Fred N. van Kempen, <decwiz@yahoo.com>
  *		Original patch for PCem by 'Tux'
@@ -355,7 +355,8 @@ zenith_init(const device_t *info, void *arg)
 
     nmi_init();
 
-    pit_set_out_func(&pit, 1, pit_refresh_timer_xt);
+    /* Set up our DRAM refresh timer. */
+    pit_set_out_func(&pit, 1, m_xt_refresh_timer);
 
     /* Set up and initialize the Ricoh RP5C15 RTC. */
     dev->nvr.size = 64;
diff --git a/src/machines/machine.h b/src/machines/machine.h
index eb2c8ec..174b207 100644
--- a/src/machines/machine.h
+++ b/src/machines/machine.h
@@ -264,6 +264,9 @@ extern const char	*machine_get_config_string(const char *s);
 extern void		machine_common_init(void);
 
 /* Functions shared by other machines. */
+extern void		m_xt_refresh_timer(int new_out, int old_out);
+
+extern void		m_at_refresh_timer(int new_out, int old_out);
 extern void		m_at_common_init(void);
 extern void		m_at_init(void);
 extern void		m_at_common_ide_init(void);
diff --git a/src/pc.c b/src/pc.c
index e32f6f0..12ba844 100644
--- a/src/pc.c
+++ b/src/pc.c
@@ -8,7 +8,7 @@
  *
  *		Main emulator module where most things are controlled.
  *
- * Version:	@(#)pc.c	1.0.74	2019/05/02
+ * Version:	@(#)pc.c	1.0.75	2019/05/05
  *
  * Authors:	Fred N. van Kempen, <decwiz@yahoo.com>
  *		Miran Grca, <mgrca8@gmail.com>
@@ -56,9 +56,9 @@
 #include "io.h"
 #include "mem.h"
 #include "rom.h"
+#include "devices/system/clk.h"
 #include "devices/system/dma.h"
 #include "devices/system/pic.h"
-#include "devices/system/pit.h"
 #include "random.h"
 #include "timer.h"
 #include "device.h"
@@ -1199,7 +1199,7 @@ pc_set_speed(int turbo)
 
     if (cpu_get_type() >= CPU_286) {
 	/* For 286+, we are done. */
-	pit_setclock(speed);
+	clk_setup(speed);
     } else {
 	/*
 	 * Not so easy for PC and XT class machines.
@@ -1210,9 +1210,9 @@ pc_set_speed(int turbo)
 	 * much all cases, the original 4.77MHz setting.
 	 */
 	if (turbo)
-		pit_setclock(14318184);	// speed * xt_multi ?
+		clk_setup(14318184);	// speed * xt_multi ?
 	  else
-		pit_setclock(14318184);
+		clk_setup(14318184);
     }
 
     /*
diff --git a/src/win/mingw/Makefile.MinGW b/src/win/mingw/Makefile.MinGW
index 39ed7fe..3030007 100644
--- a/src/win/mingw/Makefile.MinGW
+++ b/src/win/mingw/Makefile.MinGW
@@ -8,7 +8,7 @@
 #
 #		Makefile for Windows systems using the MinGW32 environment.
 #
-# Version:	@(#)Makefile.mingw	1.0.85	2019/05/02
+# Version:	@(#)Makefile.mingw	1.0.86	2019/05/05
 #
 # Author:	Fred N. van Kempen, <decwiz@yahoo.com>
 #
@@ -721,8 +721,8 @@ CPUOBJ		:= cpu.o cpu_table.o \
 		    808x.o 386.o x86seg.o x87.o \
 		    386_dynarec.o $(DYNARECOBJ)
 
-SYSOBJ		:= dma.o nmi.o pic.o pit.o ppi.o pci.o mca.o mcr.o \
-		   memregs.o nvr_at.o nvr_ps2.o
+SYSOBJ		:= clk.o dma.o nmi.o pic.o pit.o ppi.o pci.o mca.o \
+		   mcr.o memregs.o nvr_at.o nvr_ps2.o
 
 CHIPOBJ		:= neat.o scat.o headland.o \
 		    acc2168.o ali1429.o opti495.o sis471.o sis496.o \
diff --git a/src/win/msvc/Makefile.VC b/src/win/msvc/Makefile.VC
index 4433559..22bfda5 100644
--- a/src/win/msvc/Makefile.VC
+++ b/src/win/msvc/Makefile.VC
@@ -8,7 +8,7 @@
 #
 #		Makefile for Windows using Visual Studio 2015.
 #
-# Version:	@(#)Makefile.VC	1.0.69	2019/05/05
+# Version:	@(#)Makefile.VC	1.0.70	2019/05/05
 #
 # Author:	Fred N. van Kempen, <decwiz@yahoo.com>
 #
@@ -630,8 +630,8 @@ CPUOBJ		:= cpu.obj cpu_table.obj \
 		    808x.obj 386.obj x86seg.obj x87.obj \
 		    386_dynarec.obj $(DYNARECOBJ)
 
-SYSOBJ		:= dma.obj nmi.obj pic.obj pit.obj ppi.obj pci.obj mca.obj \
-		   mcr.obj memregs.obj nvr_at.obj nvr_ps2.obj
+SYSOBJ		:= clk.obj dma.obj nmi.obj pic.obj pit.obj ppi.obj pci.obj \
+		   mca.obj mcr.obj memregs.obj nvr_at.obj nvr_ps2.obj
 
 CHIPOBJ		:= neat.obj scat.obj headland.obj \
 		    acc2168.obj ali1429.obj opti495.obj sis471.obj sis496.obj \