Add more m9s12 files

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@3302 42af7a65-404d-4744-a932-0658087f49c3

7 files changed, 634 insertions, 4 deletions

diff --git a/nuttx/arch/hc/src/common/up_releasepending.c b/nuttx/arch/hc/src/common/up_releasepending.c
new file mode 100755
index 000000000..222aa717e
--- /dev/null
+++ b/nuttx/arch/hc/src/common/up_releasepending.c
@@ -0,0 +1,131 @@
+/****************************************************************************
+ *  arch/hc/src/common/up_releasepending.c
+ *
+ *   Copyright (C) 2010 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <sched.h>
+#include <debug.h>
+#include <nuttx/arch.h>
+
+#include "os_internal.h"
+#include "up_internal.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: up_release_pending
+ *
+ * Description:
+ *   Release and ready-to-run tasks that have collected in the pending task
+ *   list.  This can call a  context switch if a new task is placed at the
+ *   head of the ready to run list.
+ *
+ ****************************************************************************/
+
+void up_release_pending(void)
+{
+  _TCB *rtcb = (_TCB*)g_readytorun.head;
+
+  slldbg("From TCB=%p\n", rtcb);
+
+  /* Merge the g_pendingtasks list into the g_readytorun task list */
+
+  /* sched_lock(); */
+  if (sched_mergepending())
+    {
+      /* The currently active task has changed!  We will need to
+       * switch contexts.  First check if we are operating in
+       * interrupt context:
+       */
+
+      if (current_regs)
+        {
+          /* Yes, then we have to do things differently.
+           * Just copy the current_regs into the OLD rtcb.
+           */
+
+           up_savestate(rtcb->xcp.regs);
+
+          /* Restore the exception context of the rtcb at the (new) head 
+           * of the g_readytorun task list.
+           */
+
+          rtcb = (_TCB*)g_readytorun.head;
+          slldbg("New Active Task TCB=%p\n", rtcb);
+
+          /* Then switch contexts */
+
+          up_restorestate(rtcb->xcp.regs);
+        }
+
+      /* Copy the exception context into the TCB of the task that
+       * was currently active. if up_saveusercontext returns a non-zero
+       * value, then this is really the previously running task 
+       * restarting!
+       */
+
+      else if (!up_saveusercontext(rtcb->xcp.regs))
+        {
+          /* Restore the exception context of the rtcb at the (new) head 
+           * of the g_readytorun task list.
+           */
+
+          rtcb = (_TCB*)g_readytorun.head;
+          slldbg("New Active Task TCB=%p\n", rtcb);
+
+           /* Then switch contexts */
+
+          up_fullcontextrestore(rtcb->xcp.regs);
+        }
+    }
+}
diff --git a/nuttx/arch/hc/src/common/up_reprioritizertr.c b/nuttx/arch/hc/src/common/up_reprioritizertr.c
new file mode 100755
index 000000000..e17a48867
--- /dev/null
+++ b/nuttx/arch/hc/src/common/up_reprioritizertr.c
@@ -0,0 +1,187 @@
+/****************************************************************************
+ *  arch/hc/src/common/up_reprioritizertr.c
+ *
+ *   Copyright (C) 2010 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <sched.h>
+#include <debug.h>
+#include <nuttx/arch.h>
+
+#include "os_internal.h"
+#include "up_internal.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: up_reprioritize_rtr
+ *
+ * Description:
+ *   Called when the priority of a running or
+ *   ready-to-run task changes and the reprioritization will 
+ *   cause a context switch.  Two cases:
+ *
+ *   1) The priority of the currently running task drops and the next
+ *      task in the ready to run list has priority.
+ *   2) An idle, ready to run task's priority has been raised above the
+ *      the priority of the current, running task and it now has the
+ *      priority.
+ *
+ * Inputs:
+ *   tcb: The TCB of the task that has been reprioritized
+ *   priority: The new task priority
+ *
+ ****************************************************************************/
+
+void up_reprioritize_rtr(_TCB *tcb, uint8_t priority)
+{
+  /* Verify that the caller is sane */
+
+  if (tcb->task_state < FIRST_READY_TO_RUN_STATE ||
+      tcb->task_state > LAST_READY_TO_RUN_STATE
+#if SCHED_PRIORITY_MIN > 0
+      || priority < SCHED_PRIORITY_MIN
+#endif
+#if SCHED_PRIORITY_MAX < UINT8_MAX
+      || priority > SCHED_PRIORITY_MAX
+#endif
+    )
+    {
+       PANIC(OSERR_BADREPRIORITIZESTATE);
+    }
+  else
+    {
+      _TCB *rtcb = (_TCB*)g_readytorun.head;
+      bool switch_needed;
+
+      slldbg("TCB=%p PRI=%d\n", tcb, priority);
+
+      /* Remove the tcb task from the ready-to-run list.
+       * sched_removereadytorun will return true if we just
+       * remove the head of the ready to run list.
+       */
+
+      switch_needed = sched_removereadytorun(tcb);
+
+      /* Setup up the new task priority */
+
+      tcb->sched_priority = (uint8_t)priority;
+
+      /* Return the task to the specified blocked task list.
+       * sched_addreadytorun will return true if the task was
+       * added to the new list.  We will need to perform a context
+       * switch only if the EXCLUSIVE or of the two calls is non-zero
+       * (i.e., one and only one the calls changes the head of the
+       * ready-to-run list).
+       */
+
+      switch_needed ^= sched_addreadytorun(tcb);
+
+      /* Now, perform the context switch if one is needed */
+
+      if (switch_needed)
+        {
+          /* If we are going to do a context switch, then now is the right
+           * time to add any pending tasks back into the ready-to-run list.
+           * task list now
+           */
+
+          if (g_pendingtasks.head)
+            {
+              sched_mergepending();
+            }
+
+         /* Are we in an interrupt handler? */
+
+          if (current_regs)
+            {
+              /* Yes, then we have to do things differently.
+               * Just copy the current_regs into the OLD rtcb.
+               */
+
+               up_savestate(rtcb->xcp.regs);
+
+              /* Restore the exception context of the rtcb at the (new) head 
+               * of the g_readytorun task list.
+               */
+
+              rtcb = (_TCB*)g_readytorun.head;
+              slldbg("New Active Task TCB=%p\n", rtcb);
+
+              /* Then switch contexts */
+
+              up_restorestate(rtcb->xcp.regs);
+            }
+
+          /* Copy the exception context into the TCB at the (old) head of the
+           * g_readytorun Task list. if up_saveusercontext returns a non-zero
+           * value, then this is really the previously running task restarting!
+           */
+
+          else if (!up_saveusercontext(rtcb->xcp.regs))
+            {
+              /* Restore the exception context of the rtcb at the (new) head 
+               * of the g_readytorun task list.
+               */
+
+              rtcb = (_TCB*)g_readytorun.head;
+              slldbg("New Active Task TCB=%p\n", rtcb);
+
+              /* Then switch contexts */
+
+              up_fullcontextrestore(rtcb->xcp.regs);
+            }
+        }
+    }
+}
diff --git a/nuttx/arch/hc/src/m9s12/Make.defs b/nuttx/arch/hc/src/m9s12/Make.defs
index 03ba7c496..2c2c68a00 100755
--- a/nuttx/arch/hc/src/m9s12/Make.defs
+++ b/nuttx/arch/hc/src/m9s12/Make.defs
@@ -39,8 +39,9 @@ CMN_ASRCS	=
 CMN_CSRCS	= up_allocateheap.c up_blocktask.c up_copystate.c up_createstack.c \
 			  up_doirq.c up_idle.c up_initialize.c up_interruptcontext.c \
 			  up_mdelay.c up_modifyreg16.c up_modifyreg32.c up_modifyreg8.c \
-			  up_puts.c up_releasestack.c up_udelay.c up_unblocktask.c \
-			  up_usestack.c
+			  up_puts.c up_releasepending.c up_releasestack.c up_reprioritizertr.c \
+			  up_udelay.c up_unblocktask.c up_usestack.c
 
 CHIP_ASRCS	= m9s12_start.S m9s12_lowputc.S m9s12_saveusercontext.S
-CHIP_CSRCS	= m9s12_assert.c m9s12_serial.c m9s12_irq.c
+CHIP_CSRCS	= m9s12_assert.c m9s12_serial.c m9s12_initialstate.c m9s12_irq.c \
+			  m9s12_timerisr.c
diff --git a/nuttx/arch/hc/src/m9s12/m9s12_initialstate.c b/nuttx/arch/hc/src/m9s12/m9s12_initialstate.c
new file mode 100644
index 000000000..7efe77942
--- /dev/null
+++ b/nuttx/arch/hc/src/m9s12/m9s12_initialstate.c
@@ -0,0 +1,121 @@
+/****************************************************************************
+ *  arch/hc/src/m9s12/m9s12_initialstate.c
+ *
+ *   Copyright (C) 2011 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <string.h>
+
+#include <nuttx/sched.h>
+#include <arch/irq.h>
+
+#include "up_internal.h"
+
+/****************************************************************************
+ * Pre-processor Definitions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Data
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: up_initial_state
+ *
+ * Description:
+ *   A new thread is being started and a new TCB
+ *   has been created. This function is called to initialize
+ *   the processor specific portions of the new TCB.
+ *
+ *   This function must setup the intial architecture registers
+ *   and/or  stack so that execution will begin at tcb->start
+ *   on the next context switch.
+ *
+ ****************************************************************************/
+
+void up_initial_state(_TCB *tcb)
+{
+  struct xcptcontext *xcp = &tcb->xcp;
+
+  /* Initialize the initial exception register context structure */
+
+  memset(xcp, 0, sizeof(struct xcptcontext));
+
+  /* Save the initial stack pointer */
+
+  xcp->regs[REG_SPH]      = (uint16_t)tcb->adj_stack_ptr >> 8;
+  xcp->regs[REG_SPL]      = (uint16_t)tcb->adj_stack_ptr & 0xff;
+
+  /* Save the task entry point */
+
+  xcp->regs[REG_PCH]      = (uint16_t)tcb->start >> 8;
+  xcp->regs[REG_PCL]      = (uint16_t)tcb->start & 0xff;
+
+#ifndef CONFIG_HCS12_NONBANKED
+  /* Can only directly start in PPAGE 0x30 */
+
+  xcp->regs[REG_PPAGE]    = 0x30;
+#endif
+
+  /* Condition code register:
+   *
+   *   Bit 0: C — Carry/Borrow status bit
+   *   Bit 1: V — Two’s complement overflow status bit
+   *   Bit 2: Z — Zero status bit
+   *   Bit 3: N — Negative status bit
+   *   Bit 4: I — Maskable interrupt control bit
+   *   Bit 5: H — Half-carry status bit
+   *   Bit 6: X — Non-maskable interrupt control bit
+   *   Bit 7: S — STOP instruction control bit
+   */
+
+# ifdef CONFIG_SUPPRESS_INTERRUPTS
+  xcp->regs[REG_CCR]      = 0xd0;  /* Disable STOP, Mask I- and Z- interrupts */
+# else
+  xcp->regs[REG_CCR]      = 0x80;  /* Disable STOP, Enable I- and Z-interrupts */
+# endif
+}
+
diff --git a/nuttx/arch/hc/src/m9s12/m9s12_saveusercontext.S b/nuttx/arch/hc/src/m9s12/m9s12_saveusercontext.S
index da2769521..652ba4980 100755
--- a/nuttx/arch/hc/src/m9s12/m9s12_saveusercontext.S
+++ b/nuttx/arch/hc/src/m9s12/m9s12_saveusercontext.S
@@ -112,7 +112,7 @@ up_saveusercontext:
 
 	xgdx
 
-	/* Save he PPAGE register */
+	/* Save the PPAGE register */
 
 #ifndef CONFIG_HCS12_NONBANKED
 	movb	HCS12_MMC_PPAGE, 1, x+
diff --git a/nuttx/arch/hc/src/m9s12/m9s12_timerisr.c b/nuttx/arch/hc/src/m9s12/m9s12_timerisr.c
new file mode 100755
index 000000000..3839badf2
--- /dev/null
+++ b/nuttx/arch/hc/src/m9s12/m9s12_timerisr.c
@@ -0,0 +1,189 @@
+/****************************************************************************
+ * arch/hc/src/m9s12/m9s12_timerisr.c
+ *
+ *   Copyright (C) 2011 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <spudmonkey@racsa.co.cr>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <stdint.h>
+#include <time.h>
+#include <debug.h>
+
+#include <nuttx/arch.h>
+#include <arch/board/board.h>
+
+#include "clock_internal.h"
+#include "up_internal.h"
+#include "up_arch.h"
+
+#include "chip.h"
+#include "m9s12_internal.h"
+#include "m9s12_crg.h"
+
+/****************************************************************************
+ * Definitions
+ ****************************************************************************/
+
+/* The desired timer interrupt frequency is provided by the definition
+ * CLK_TCK (see include/time.h).  CLK_TCK defines the desired number of
+ * system clock ticks per second.  That value is a user configurable setting
+ * that defaults to 100 (100 ticks per second = 10 MS interval).
+ */
+
+/* The timer frequency is the OSCCLK divided down.  The divisor is
+ * (A+1)*(2**(B+9)) where:
+ *
+ *   A = MODCNT RTR[0:3]
+ *   B = PREP   RTR[4:6]
+ *
+ * Maximum and minimum values:
+ */
+
+#define MIN_PRER    1024 /* 2**10, B=1 */
+#define MAX_PRER   65536 /* 2**16, B=7 */
+ 
+#define MIN_MODCNT     1 /* A=0 */
+#define MAX_MODCNT    16 /* A=15 */
+
+/* Pick the smallest value of B for which:
+ *
+ *   OSCCLK/(MAX_MODCNT*(2**(B+9))) >= CLK_TCK >= OSCCLK/(MIN_MODCNT*(2**(B+9)))
+ */
+
+#if CLK_TCK >= HCS12_OSCCLK/(MAX_MODCNT*1024) && HCS12_OSCCLK/(MIN_MODCNT*1024)
+#  define PRER_VALUE      1
+#  define PRER_DIV     1024
+#elif CLK_TCK >= HCS12_OSCCLK/(MAX_MODCNT*2048) && HCS12_OSCCLK/(MIN_MODCNT*2048)
+#  define PRER_VALUE      2
+#  define PRER_DIV     2048
+#elif CLK_TCK >= HCS12_OSCCLK/(MAX_MODCNT*4096) && HCS12_OSCCLK/(MIN_MODCNT*4096)
+#  define PRER_VALUE      3
+#  define PRER_DIV     4096
+#elif CLK_TCK >= HCS12_OSCCLK/(MAX_MODCNT*8192) && HCS12_OSCCLK/(MIN_MODCNT*8192)
+#  define PRER_VALUE      4
+#  define PRER_DIV     8192
+#elif CLK_TCK >= HCS12_OSCCLK/(MAX_MODCNT*16384) && HCS12_OSCCLK/(MIN_MODCNT*16384)
+#  define PRER_VALUE      5
+#  define PRER_DIV    16384
+#elif CLK_TCK >= HCS12_OSCCLK/(MAX_MODCNT*32768) && HCS12_OSCCLK/(MIN_MODCNT*32768)
+#  define PRER_VALUE      6
+#  define PRER_DIV    32768
+#elif CLK_TCK >= HCS12_OSCCLK/(MAX_MODCNT*65536) && HCS12_OSCCLK/(MIN_MODCNT*65536)
+#  define PRER_VALUE      7
+#  define PRER_DIV    65536
+#else
+#  error "Cannot generate CLK_TCK from HCSCLK_OSCCLK"
+#endif
+
+/* Now we can simply calculate A from:
+ *
+ * CLK_TCK = OSCCLK/((A+1)*PRER_DIV)
+ * OSCCLK / (CLK_TCK * PRER_DIV) - 1
+ */
+
+ #define MODCNT_DENOM  ((uint32_t)CLK_TCK * (uint32_t)PRER_DIV)
+ #define MODCNT_VALUE  ((((uint32_t)HCS12_OSCCLK  + (MODCNT_DENOM/2))/ MODCNT_DENOM) - 1)
+
+/****************************************************************************
+ * Private Types
+ ****************************************************************************/
+
+/****************************************************************************
+ * Private Function Prototypes
+ ****************************************************************************/
+
+/****************************************************************************
+ * Global Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Function:  up_timerisr
+ *
+ * Description:
+ *   The timer ISR will perform a variety of services for various portions
+ *   of the systems.
+ *
+ ****************************************************************************/
+
+int up_timerisr(int irq, uint32_t *regs)
+{
+  /* Clear real time interrupt flag */
+
+  putreg8(CRG_CRGFLG_RTIF, HCS12_CRG_CRGFLG);
+
+  /* Process timer interrupt */
+
+  sched_process_timer();
+  return 0;
+}
+
+/****************************************************************************
+ * Function:  up_timerinit
+ *
+ * Description:
+ *   This function is called during start-up to initialize the system timer
+ *   interrupt.
+ *
+ ****************************************************************************/
+
+void up_timerinit(void)
+{
+  uint32_t tmp;
+  uint8_t  regval;
+
+  /* Configure hardware RTI timer (with a hack to avoid and integer overflow
+   * error at compile time.. hopefully the optimizer will eliminate these
+   * uint32_t operations).
+   */
+
+  tmp = MODCNT_VALUE << CRG_RTICTL_MODCNT_SHIFT | PRER_VALUE << CRG_RTICTL_PRER_SHIFT;
+  putreg8((uint8_t)tmp, HCS12_CRG_RTICTL);
+
+  /* Attach the timer interrupt vector */
+
+  (void)irq_attach(HCS12_IRQ_VRTI, (xcpt_t)up_timerisr);
+
+  /* Enable RTI interrupt by setting the RTIE bit */
+
+  regval  = getreg8(HCS12_CRG_CRGINT);
+  regval |= CRG_CRGINT_RTIE;
+  putreg8(regval, HCS12_CRG_CRGINT);
+
+  /* And enable the timer interrupt */
+
+  up_enable_irq(HCS12_IRQ_VRTI);
+}
diff --git a/nuttx/configs/demo9s12ne64/include/board.h b/nuttx/configs/demo9s12ne64/include/board.h
index d4c30013c..9420b67dd 100755
--- a/nuttx/configs/demo9s12ne64/include/board.h
+++ b/nuttx/configs/demo9s12ne64/include/board.h
@@ -52,6 +52,7 @@
 
 /* Clocking *************************************************************************/
 
+#define HCS12_OSCCLK      16000000 /* 16MHz */
 
 /* LED definitions ******************************************************************/