diff --git a/sdk/xtdk/amd64/hltypes.h b/sdk/xtdk/amd64/hltypes.h
index e0aefa7..c52440c 100644
--- a/sdk/xtdk/amd64/hltypes.h
+++ b/sdk/xtdk/amd64/hltypes.h
@@ -109,6 +109,28 @@
 #define PIT_DATA_PORT1                                  0x41
 #define PIT_DATA_PORT2                                  0x42
 
+/* PIT related definitions */
+#define PIT_BASE_FREQUENCY                              1193182
+
+/* PIT Access Mode: Defines how the CPU reads or writes the counter value */
+#define PIT_CMD_ACCESS_LATCH                            0x00
+#define PIT_CMD_ACCESS_LOWBYTE_ONLY                     0x10
+#define PIT_CMD_ACCESS_HIGHBYTE_ONLY                    0x20
+#define PIT_CMD_ACCESS_LOWBYTE_HIGHBYTE                 0x30
+
+/* PIT Channel Selection: Specifies the physical timer channel to configure */
+#define PIT_CMD_CHANNEL0                                0x00
+#define PIT_CMD_CHANNEL1                                0x40
+#define PIT_CMD_CHANNEL2                                0x80
+
+/* PIT Operating Mode: Defines the hardware behavior and the generated waveform */
+#define PIT_MODE0_INT_ON_TERMINAL_COUNT                 0x00
+#define PIT_MODE1_ONESHOT                               0x02
+#define PIT_MODE2_RATE_GENERATOR                        0x04
+#define PIT_MODE3_SQUARE_WAVE_GEN                       0x06
+#define PIT_MODE4_SOFTWARE_STROBE                       0x08
+#define PIT_MODE5_HARDWARE_STROBE                       0x0A
+
 /* CMOS controller access ports */
 #define CMOS_SELECT_PORT                                0x70
 #define CMOS_DATA_PORT                                  0x71
diff --git a/sdk/xtdk/hltypes.h b/sdk/xtdk/hltypes.h
index a6a489f..eda03bd 100644
--- a/sdk/xtdk/hltypes.h
+++ b/sdk/xtdk/hltypes.h
@@ -101,6 +101,9 @@
 #define ACPI_MADT_PLACE_ENABLED                     0 /* Processor Local APIC CPU Enabled */
 #define ACPI_MADT_PLAOC_ENABLED                     1 /* Processor Local APIC Online Capable */
 
+/* ACPI Timer frequency */
+#define ACPI_PM_TIMER_FREQUENCY                     3579545
+
 /* ACPI address space definitions */
 #define ACPI_ADDRESS_SPACE_MEMORY                   0x00
 
@@ -186,7 +189,7 @@
 #define COMPORT_REG_SR                              0x07 /* Scratch Register */
 
 /* Minimum and maximum profile intervals */
-#define MIN_PROFILE_INTERVAL 1000
+#define MIN_PROFILE_INTERVAL 10000
 #define MAX_PROFILE_INTERVAL 10000000
 
 
diff --git a/sdk/xtdk/i686/hltypes.h b/sdk/xtdk/i686/hltypes.h
index 857c801..4dee845 100644
--- a/sdk/xtdk/i686/hltypes.h
+++ b/sdk/xtdk/i686/hltypes.h
@@ -117,6 +117,28 @@
 #define PIT_DATA_PORT1                                  0x41
 #define PIT_DATA_PORT2                                  0x42
 
+/* PIT related definitions */
+#define PIT_BASE_FREQUENCY                              1193182
+
+/* PIT Access Mode: Defines how the CPU reads or writes the counter value */
+#define PIT_CMD_ACCESS_LATCH                            0x00
+#define PIT_CMD_ACCESS_LOWBYTE_ONLY                     0x10
+#define PIT_CMD_ACCESS_HIGHBYTE_ONLY                    0x20
+#define PIT_CMD_ACCESS_LOWBYTE_HIGHBYTE                 0x30
+
+/* PIT Channel Selection: Specifies the physical timer channel to configure */
+#define PIT_CMD_CHANNEL0                                0x00
+#define PIT_CMD_CHANNEL1                                0x40
+#define PIT_CMD_CHANNEL2                                0x80
+
+/* PIT Operating Mode: Defines the hardware behavior and the generated waveform */
+#define PIT_MODE0_INT_ON_TERMINAL_COUNT                 0x00
+#define PIT_MODE1_ONESHOT                               0x02
+#define PIT_MODE2_RATE_GENERATOR                        0x04
+#define PIT_MODE3_SQUARE_WAVE_GEN                       0x06
+#define PIT_MODE4_SOFTWARE_STROBE                       0x08
+#define PIT_MODE5_HARDWARE_STROBE                       0x0A
+
 /* CMOS controller access ports */
 #define CMOS_SELECT_PORT                                0x70
 #define CMOS_DATA_PORT                                  0x71