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31 ******************************************************************************/
32 /*****************************************************************************/
37 * This function provides a microsecond delay using the Global Timer register in
38 * the ARM Cortex A9 MP core.
41 * MODIFICATION HISTORY:
43 * Ver Who Date Changes
44 * ----- -------- -------- -----------------------------------------------
45 * 1.00a ecm/sdm 11/11/09 First release
46 * 3.07a sgd 07/05/12 Upadted micro sleep function to make use Global Timer
47 * 4.2 pkp 08/04/14 Removed unimplemented nanosleep routine as it is not
48 * possible to generate timer in nanosecond due to
49 * limited cpu frequency
50 * 6.0 asa 08/15/16 Updated the usleep signature. Fix for CR#956899.
51 * 6.6 srm 10/18/17 Updated sleep routines to support user configurable
52 * implementation. Now sleep routines will use Timer
53 * specified by the user (i.e. Global timer/TTC timer)
56 ******************************************************************************/
57 /***************************** Include Files *********************************/
61 #include "xparameters.h"
62 #include "xil_types.h"
63 #include "xpseudo_asm.h"
64 #include "xreg_cortexa9.h"
66 #if defined (SLEEP_TIMER_BASEADDR)
67 #include "xil_sleeptimer.h"
70 /**************************** Constant Definitions ************************/
71 #if defined (SLEEP_TIMER_BASEADDR)
72 #define COUNTS_PER_USECOND (SLEEP_TIMER_FREQUENCY / 1000000)
74 /* Global Timer is always clocked at half of the CPU frequency */
75 #define COUNTS_PER_USECOND (XPAR_CPU_CORTEXA9_CORE_CLOCK_FREQ_HZ / (2U*1000000U))
78 /*****************************************************************************/
81 * This API gives a delay in microseconds
83 * @param useconds requested
85 * @return 0 if the delay can be achieved, -1 if the requested delay
90 ****************************************************************************/
91 int usleep_A9(unsigned long useconds)
93 #if defined (SLEEP_TIMER_BASEADDR)
94 Xil_SleepTTCCommon(useconds, COUNTS_PER_USECOND);
99 tEnd = tCur + (((XTime) useconds) * COUNTS_PER_USECOND);
102 XTime_GetTime(&tCur);
103 } while (tCur < tEnd);