atsam: Add support for SAM E70

Signed-off-by: Alex Maclean <monkeh@monkeh.net>

1 files changed, 74 insertions, 0 deletions

diff --git a/src/atsam/same70_sysinit.c b/src/atsam/same70_sysinit.c
new file mode 100644
index 00000000..d4d98483
--- /dev/null
+++ b/src/atsam/same70_sysinit.c
@@ -0,0 +1,74 @@
+// This code is from lib/sam4e/gcc/system_sam4e.c and modified for the SAM E70
+
+#include "internal.h"
+
+/* Clock Settings (300MHz) */
+#define SYS_BOARD_OSCOUNT   (CKGR_MOR_MOSCXTST(0x8U))
+#define SYS_BOARD_PLLAR     (CKGR_PLLAR_ONE                             \
+                             | CKGR_PLLAR_MULA(0x18U)                   \
+                             | CKGR_PLLAR_PLLACOUNT(0x3fU)              \
+                             | CKGR_PLLAR_DIVA_BYPASS)
+#define SYS_BOARD_MCKR      (PMC_MCKR_MDIV_PCK_DIV2 | PMC_MCKR_CSS_PLLA_CLK)
+
+/* Key to unlock MOR register */
+#define SYS_CKGR_MOR_KEY_VALUE CKGR_MOR_KEY(0x37)
+
+uint32_t SystemCoreClock = CHIP_FREQ_MAINCK_RC_12MHZ;
+
+void SystemInit( void )
+{
+    /* Set FWS according to SYS_BOARD_MCKR configuration */
+    EFC->EEFC_FMR = EEFC_FMR_FWS(6) | EEFC_FMR_CLOE;
+
+    /* Initialize main oscillator */
+    if ( !(PMC->CKGR_MOR & CKGR_MOR_MOSCSEL) )
+    {
+        PMC->CKGR_MOR = (SYS_CKGR_MOR_KEY_VALUE | SYS_BOARD_OSCOUNT
+                         | CKGR_MOR_MOSCRCEN | CKGR_MOR_MOSCXTEN);
+
+        while ( !(PMC->PMC_SR & PMC_SR_MOSCXTS) )
+        {
+        }
+    }
+
+    /* Switch to 3-20MHz Xtal oscillator */
+    PMC->CKGR_MOR = (SYS_CKGR_MOR_KEY_VALUE | SYS_BOARD_OSCOUNT
+                     | CKGR_MOR_MOSCRCEN | CKGR_MOR_MOSCXTEN
+                     | CKGR_MOR_MOSCSEL);
+
+    while ( !(PMC->PMC_SR & PMC_SR_MOSCSELS) )
+    {
+    }
+
+    PMC->PMC_MCKR = ((PMC->PMC_MCKR & ~(uint32_t)PMC_MCKR_CSS_Msk)
+                     | PMC_MCKR_CSS_MAIN_CLK);
+
+    while ( !(PMC->PMC_SR & PMC_SR_MCKRDY) )
+    {
+    }
+
+    /* Initialize PLLA */
+    PMC->CKGR_PLLAR = SYS_BOARD_PLLAR;
+    while ( !(PMC->PMC_SR & PMC_SR_LOCKA) )
+    {
+    }
+
+    /* Switch to main clock */
+    PMC->PMC_MCKR = ((SYS_BOARD_MCKR & ~PMC_MCKR_CSS_Msk)
+                     | PMC_MCKR_CSS_MAIN_CLK);
+    while ( !(PMC->PMC_SR & PMC_SR_MCKRDY) )
+    {
+    }
+
+    /* Switch to PLLA */
+    PMC->PMC_MCKR = SYS_BOARD_MCKR;
+    while ( !(PMC->PMC_SR & PMC_SR_MCKRDY) )
+    {
+    }
+
+    SystemCoreClock = CHIP_FREQ_CPU_MAX;
+
+    // Configure PCK6 for TC use
+    PMC->PMC_PCK[6] = PMC_PCK_CSS_MCK | PMC_PCK_PRES(2);
+    PMC->PMC_SCER = PMC_SCER_PCK6;
+}