2 files changed, 199 insertions, 0 deletions
diff --git a/at91lib/peripherals/pit/pit.c b/at91lib/peripherals/pit/pit.c
new file mode 100644
index 0000000..f15610c
--- /dev/null
+++ b/at91lib/peripherals/pit/pit.c
@@ -0,0 +1,122 @@
+/* ----------------------------------------------------------------------------
+ *         ATMEL Microcontroller Software Support 
+ * ----------------------------------------------------------------------------
+ * Copyright (c) 2008, Atmel Corporation
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the disclaimer below.
+ *
+ * Atmel's name may not be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * DISCLAIMER: THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE
+ * DISCLAIMED. IN NO EVENT SHALL ATMEL 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.
+ * ----------------------------------------------------------------------------
+ */
+
+//------------------------------------------------------------------------------
+//         Headers
+//------------------------------------------------------------------------------
+
+#include "pit.h"
+#include <board.h>
+
+//------------------------------------------------------------------------------
+//         Global functions
+//------------------------------------------------------------------------------
+
+//------------------------------------------------------------------------------
+/// Initialize the Periodic Interval Timer to generate a tick at the specified
+/// period, given the current master clock frequency.
+/// \param period  Period in ľsecond.
+/// \param pit_frequency  Master clock frequency in MHz.
+//------------------------------------------------------------------------------
+void PIT_Init(unsigned int period, unsigned int pit_frequency)
+{
+    AT91C_BASE_PITC->PITC_PIMR = period? (period * pit_frequency + 8) >> 4 : 0;
+    AT91C_BASE_PITC->PITC_PIMR |= AT91C_PITC_PITEN;
+}
+
+//------------------------------------------------------------------------------
+/// Set the Periodic Interval Value of the PIT.
+/// \param piv  PIV value to set.
+//------------------------------------------------------------------------------
+void PIT_SetPIV(unsigned int piv)
+{
+    AT91C_BASE_PITC->PITC_PIMR = (AT91C_BASE_PITC->PITC_PIMR & AT91C_PITC_PIV)
+                                 | piv;
+}
+
+//------------------------------------------------------------------------------
+/// Enables the PIT if this is not already the case.
+//------------------------------------------------------------------------------
+void PIT_Enable(void)
+{
+    AT91C_BASE_PITC->PITC_PIMR |= AT91C_PITC_PITEN;
+}
+
+//----------------------------------------------------------------------------
+/// Enable the PIT periodic interrupt.
+//----------------------------------------------------------------------------
+void PIT_EnableIT(void)
+{
+    AT91C_BASE_PITC->PITC_PIMR |= AT91C_PITC_PITIEN;
+}
+
+//------------------------------------------------------------------------------
+/// Disables the PIT periodic interrupt.
+//------------------------------------------------------------------------------
+void PIT_DisableIT(void)
+{
+    AT91C_BASE_PITC->PITC_PIMR &= ~AT91C_PITC_PITIEN;
+}
+
+//------------------------------------------------------------------------------
+/// Returns the value of the PIT mode register.
+/// \return PIT_MR value.
+//------------------------------------------------------------------------------
+unsigned int PIT_GetMode(void)
+{
+    return AT91C_BASE_PITC->PITC_PIMR;
+}
+
+//------------------------------------------------------------------------------
+/// Returns the value of the PIT status register, clearing it as a side effect.
+/// \return PIT_SR value.
+//------------------------------------------------------------------------------
+unsigned int PIT_GetStatus(void)
+{
+    return AT91C_BASE_PITC->PITC_PISR;
+}
+
+//------------------------------------------------------------------------------
+/// Returns the value of the PIT Image Register, to read PICNT and CPIV without
+/// clearing the current values.
+/// \return PIT_PIIR value.
+//------------------------------------------------------------------------------
+unsigned int PIT_GetPIIR(void)
+{
+    return AT91C_BASE_PITC->PITC_PIIR;
+}
+
+//------------------------------------------------------------------------------
+/// Returns the value of the PIT Value Register, clearing it as a side effect.
+/// \return PIT_PIVR value.
+//------------------------------------------------------------------------------
+unsigned int PIT_GetPIVR(void)
+{
+    return AT91C_BASE_PITC->PITC_PIVR;
+}
diff --git a/at91lib/peripherals/pit/pit.h b/at91lib/peripherals/pit/pit.h
new file mode 100644
index 0000000..12aad31
--- /dev/null
+++ b/at91lib/peripherals/pit/pit.h
@@ -0,0 +1,77 @@
+/* ----------------------------------------------------------------------------
+ *         ATMEL Microcontroller Software Support 
+ * ----------------------------------------------------------------------------
+ * Copyright (c) 2008, Atmel Corporation
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright notice,
+ * this list of conditions and the disclaimer below.
+ *
+ * Atmel's name may not be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * DISCLAIMER: THIS SOFTWARE IS PROVIDED BY ATMEL "AS IS" AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT ARE
+ * DISCLAIMED. IN NO EVENT SHALL ATMEL 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.
+ * ----------------------------------------------------------------------------
+ */
+
+//------------------------------------------------------------------------------
+/// \unit
+///
+/// !Purpose
+///
+/// Interface for configuration the Periodic Interval Timer (PIT) peripheral.
+///
+/// !Usage
+///
+/// -# Initialize the PIT with the desired period using PIT_Init().
+///    Alternatively, the Periodic Interval Value (PIV) can be configured
+///    manually using PIT_SetPIV().
+/// -# Start the PIT counting using PIT_Enable().
+/// -# Enable & disable the PIT interrupt using PIT_EnableIT() and
+///    PIT_DisableIT().
+/// -# Retrieve the current status of the PIT using PIT_GetStatus().
+/// -# To get the current value of the internal counter and the number of ticks
+///    that have occurred, use either PIT_GetPIVR() or PIT_GetPIIR() depending
+///    on whether you want the values to be cleared or not.
+//------------------------------------------------------------------------------
+
+#ifndef PIT_H
+#define PIT_H
+
+//------------------------------------------------------------------------------
+//         Global Functions
+//------------------------------------------------------------------------------
+
+extern void PIT_Init(unsigned int period, unsigned int pit_frequency);
+
+extern void PIT_SetPIV(unsigned int piv);
+
+extern void PIT_Enable(void);
+
+extern void PIT_EnableIT(void);
+
+extern void PIT_DisableIT(void);
+
+extern unsigned int PIT_GetMode(void);
+
+extern unsigned int PIT_GetStatus(void);
+
+extern unsigned int PIT_GetPIIR(void);
+
+extern unsigned int PIT_GetPIVR(void);
+
+#endif //#ifndef PIT_H
+