diff options
Diffstat (limited to 'boards/at91sam7a3-ek/board_lowlevel.c')
| -rw-r--r-- | boards/at91sam7a3-ek/board_lowlevel.c | 167 |
1 files changed, 167 insertions, 0 deletions
diff --git a/boards/at91sam7a3-ek/board_lowlevel.c b/boards/at91sam7a3-ek/board_lowlevel.c new file mode 100644 index 0000000..647cbe6 --- /dev/null +++ b/boards/at91sam7a3-ek/board_lowlevel.c @@ -0,0 +1,167 @@ +/* ----------------------------------------------------------------------------
+ * 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
+///
+/// Provides the low-level initialization function that gets called on chip
+/// startup.
+///
+/// !Usage
+///
+/// LowLevelInit() is called in #board_cstartup.S#.
+//------------------------------------------------------------------------------
+
+//------------------------------------------------------------------------------
+// Headers
+//------------------------------------------------------------------------------
+
+#include "board.h"
+#include "board_memories.h"
+#include <pmc/pmc.h>
+
+//------------------------------------------------------------------------------
+// Internal definitions
+//------------------------------------------------------------------------------
+// Startup time of main oscillator (in number of slow clock ticks).
+#define BOARD_OSCOUNT (AT91C_CKGR_OSCOUNT & (0x40 << 8))
+
+// USB PLL divisor value to obtain a 48MHz clock.
+#define BOARD_USBDIV AT91C_CKGR_USBDIV_1
+
+// PLL frequency range.
+#define BOARD_CKGR_PLL AT91C_CKGR_OUT_0
+
+// PLL startup time (in number of slow clock ticks).
+#define BOARD_PLLCOUNT (16 << 8)
+
+// PLL MUL value.
+#define BOARD_MUL (AT91C_CKGR_MUL & (72 << 16))
+
+// PLL DIV value.
+#define BOARD_DIV (AT91C_CKGR_DIV & 14)
+
+// Master clock prescaler value.
+#define BOARD_PRESCALER AT91C_PMC_PRES_CLK_2
+
+//------------------------------------------------------------------------------
+// Internal functions
+//------------------------------------------------------------------------------
+//------------------------------------------------------------------------------
+/// Default spurious interrupt handler. Infinite loop.
+//------------------------------------------------------------------------------
+void defaultSpuriousHandler( void )
+{
+ while (1);
+}
+
+//------------------------------------------------------------------------------
+/// Default handler for fast interrupt requests. Infinite loop.
+//------------------------------------------------------------------------------
+void defaultFiqHandler( void )
+{
+ while (1);
+}
+
+//------------------------------------------------------------------------------
+/// Default handler for standard interrupt requests. Infinite loop.
+//------------------------------------------------------------------------------
+void defaultIrqHandler( void )
+{
+ while (1);
+}
+
+//------------------------------------------------------------------------------
+// Exported functions
+//------------------------------------------------------------------------------
+//------------------------------------------------------------------------------
+/// Performs the low-level initialization of the chip. This includes EFC, master
+/// clock, AIC & watchdog configuration, as well as memory remapping.
+//------------------------------------------------------------------------------
+void LowLevelInit( void )
+{
+ unsigned char i;
+
+ // Set flash wait states in the EFC
+ // 48MHz = 1 wait state
+ AT91C_BASE_MC->MC_FMR = AT91C_MC_FWS_1FWS;
+
+ // Initialize main oscillator
+ AT91C_BASE_PMC->PMC_MOR = BOARD_OSCOUNT | AT91C_CKGR_MOSCEN;
+ while (!(AT91C_BASE_PMC->PMC_SR & AT91C_PMC_MOSCS));
+
+ // Initialize PLL at 96MHz (96.109) and USB clock to 48MHz
+ AT91C_BASE_PMC->PMC_PLLR = BOARD_USBDIV | BOARD_CKGR_PLL | BOARD_PLLCOUNT
+ | BOARD_MUL | BOARD_DIV;
+ while (!(AT91C_BASE_PMC->PMC_SR & AT91C_PMC_LOCK));
+
+ // Wait for the master clock if it was already initialized
+ while (!(AT91C_BASE_PMC->PMC_SR & AT91C_PMC_MCKRDY));
+
+ // Switch to slow clock + prescaler
+ AT91C_BASE_PMC->PMC_MCKR = BOARD_PRESCALER;
+ while (!(AT91C_BASE_PMC->PMC_SR & AT91C_PMC_MCKRDY));
+
+ // Switch to fast clock + prescaler
+ AT91C_BASE_PMC->PMC_MCKR |= AT91C_PMC_CSS_PLL_CLK;
+ while (!(AT91C_BASE_PMC->PMC_SR & AT91C_PMC_MCKRDY));
+
+ // Initialize AIC
+ AT91C_BASE_AIC->AIC_IDCR = 0xFFFFFFFF;
+ AT91C_BASE_AIC->AIC_SVR[0] = (unsigned int) defaultFiqHandler;
+ for (i = 1; i < 31; i++) {
+
+ AT91C_BASE_AIC->AIC_SVR[i] = (unsigned int) defaultIrqHandler;
+ }
+ AT91C_BASE_AIC->AIC_SPU = (unsigned int) defaultSpuriousHandler;
+
+ // Unstack nested interrupts
+ for (i = 0; i < 8 ; i++) {
+
+ AT91C_BASE_AIC->AIC_EOICR = 0;
+ }
+
+ // Enable Debug mode
+ AT91C_BASE_AIC->AIC_DCR = AT91C_AIC_DCR_PROT;
+
+ // Watchdog initialization
+ AT91C_BASE_WDTC->WDTC_WDMR = AT91C_WDTC_WDDIS;
+
+ // Remap the internal SRAM at 0x0
+ BOARD_RemapRam();
+
+ // Disable RTT and PIT interrupts (potential problem when program A
+ // configures RTT, then program B wants to use PIT only, interrupts
+ // from the RTT will still occur since they both use AT91C_ID_SYS)
+ AT91C_BASE_RTTC->RTTC_RTMR &= ~(AT91C_RTTC_ALMIEN | AT91C_RTTC_RTTINCIEN);
+ AT91C_BASE_PITC->PITC_PIMR &= ~AT91C_PITC_PITIEN;
+}
+
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