+/* (CC-BY-NC-SA) ROBIN KRENS - ROBIN @ ROBINKRENS.NL
+ *
+ * $LOG$
+ * 2019/8/14 - ROBIN KRENS
+ * Initial version
+ *
+ * $DESCRIPTION$
+ * SysTick of Cortex M* MCUs. Have a look at the more complex RTC
+ * in case more accurate timing is needed.
+ *
+ *
+ * */
+
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
-#include <stm32.h>
-#include <mmap.h>
+#include <sys/robsys.h>
+#include <sys/mmap.h>
+
+#include <lib/regfunc.h>
+#include <lib/tinyprintf.h>
+
+struct interrupt_frame {
+
+ uint32_t r0; // N-32
+ uint32_t r1;
+ uint32_t r2;
+ uint32_t r3;
+ uint32_t r12;
+ uint32_t lr;
+ uint32_t pc;
+ uint32_t psr; // N-4
+};
+
+//__attribute__ ((interrupt))
+void * systick_handler(/* struct interrupt_frame * frame */) {
-void * systick_handler() {
+ printf("Ticking...\n");
- *RANDOM_ADDR = (volatile uint32_t) 0x10101010 ;
}
-void systick_init() {
- /* Enable the counter and enable the interrupt
- * associated with it */
- *STK_CTRL = (volatile uint32_t) 0x00000003;
+__attribute__ ((naked))
+ void * pendsv_handler_c(void) {
+//
+// asm volatile ("push {r0-r11, lr}");
+// asm volatile ("mrs %0, psp" : "=r" (oldpsp));
+// asm volatile ("push {lr}");
+//
+// //asm volatile ("push {lr}");
+//
+// //printf("FROM MSP %x", oldpsp);
+// //PSP_array[curr_task] = oldpsp;
+// //curr_task = next_task;
+// //newpsp = PSP_array[next_task];
+//
+// asm volatile ("msr psp, %0" : : "r" (newpsp));
+//
+// asm volatile("pop {lr}");
+// //asm volatile ("pop {r0-r12}");
+// asm volatile("bx lr"); // return
+}
- /* The counter reload register here holds
- * 0x1000 -- that's 4096 clock cycles -- if
- * it is down to zero it is restores the value */
- *STK_RELOAD = (volatile uint32_t) 0x00000400;
+uint32_t set_psp(uint32_t) __attribute__( ( naked ) );
+uint32_t set_psp(uint32_t stackie) {
+
+ asm volatile ("msr psp, r0" "\n\t"
+ "bx lr");
+}
+
+void systick_init() {
/* Every time the counter counts down to zero
- * a systick exception is asserted. Systick has
+ * a systick exception is invoked. Systick has
* exception number 15. in the vector table */
ivt_set_gate(15, systick_handler, 0);
+
+ /* Get calibration and set this to 1 sec
+ * !Most boards have a 1 ms or 10 ms
+ * calibration value */
+ int calib = (*STK_CALIB << 0) * 200;
+
+ /* The counter reload registers counts down to zero
+ * and then it is restores the value */
+ rwrite(STK_RELOAD, calib);
+
+ /* Enable the counter and enable the interrupt
+ * associated with it */
+ rsetbit(STK_CTRL, 0);
+ rsetbit(STK_CTRL, 1);
+
}