1 files changed, 80 insertions, 0 deletions
diff --git a/src/pru/pwm_test.c b/src/pru/pwm_test.c
new file mode 100644
index 0000000..df8bbf0
--- /dev/null
+++ b/src/pru/pwm_test.c
@@ -0,0 +1,80 @@
+/* 
+ *
+ *  pwm tester
+ *	The on cycle and off cycles are stored in each PRU's Data memory
+ *
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+
+#define PRU_ADDR		0x4A300000		// Start of PRU memory Page 184 am335x TRM
+#define PRU_LEN			0x80000			// Length of PRU memory
+#define PRU0_DRAM		0x00000			// Offset to DRAM
+#define PRU1_DRAM		0x02000
+#define PRU_SHAREDMEM	0x10000			// Offset to shared memory
+
+#define CYCLES_PER_SECOND 200000000
+#define CYCLES_PER_PERIOD (CYCLES_PER_SECOND / 800)
+
+uint32_t	*pru0DRAM_32int_ptr;		// Points to the start of local DRAM
+uint32_t	*pru1DRAM_32int_ptr;		// Points to the start of local DRAM
+uint32_t	*prusharedMem_32int_ptr;	// Points to the start of the shared memory
+
+/*******************************************************************************
+* int start_pwm_count(int ch, int countOn, int countOff)
+* 
+* Starts a pwm pulse on for countOn and off for countOff to a single channel (ch)
+*******************************************************************************/
+int start_pwm_count(uint32_t duty_cycle) {
+	uint32_t *pruDRAM_32int_ptr = pru0DRAM_32int_ptr;
+    uint32_t old_duty_cycle = pruDRAM_32int_ptr[0];
+    uint32_t old_count_on = (100 - (100 - old_duty_cycle)) * CYCLES_PER_PERIOD / 100;
+    uint32_t old_count_off = (100 - old_duty_cycle) * CYCLES_PER_PERIOD / 100;
+    uint32_t new_count_on = (100 - (100 - duty_cycle)) * CYCLES_PER_PERIOD / 100;
+    uint32_t new_count_off = (100 - duty_cycle) * CYCLES_PER_PERIOD / 100;
+	
+	printf("old:\n\tcountOn: %d, countOff: %d, count: %d\nnew:\n\tcountOn: %d, countOff: %d, count: %d\n", old_count_on, old_count_off, old_count_off + old_count_on, new_count_on, new_count_off, new_count_off + new_count_on);
+	// write to PRU shared memory
+	pruDRAM_32int_ptr[0] = duty_cycle;	// On time
+	return 0;
+}
+
+int main(int argc, char *argv[])
+{
+	uint32_t *pru;		// Points to start of PRU memory.
+	int	fd;
+	printf("Servo tester\n");
+	
+	fd = open ("/dev/mem", O_RDWR | O_SYNC);
+	if (fd == -1) {
+		printf ("ERROR: could not open /dev/mem.\n\n");
+		return 1;
+	}
+	pru = mmap (0, PRU_LEN, PROT_READ | PROT_WRITE, MAP_SHARED, fd, PRU_ADDR);
+	if (pru == MAP_FAILED) {
+		printf ("ERROR: could not map memory.\n\n");
+		return 1;
+	}
+	close(fd);
+	printf ("Using /dev/mem.\n");
+	
+	pru0DRAM_32int_ptr =     pru + PRU0_DRAM/4 + 0x200/4;	// Points to 0x200 of PRU0 memory
+	pru1DRAM_32int_ptr =     pru + PRU1_DRAM/4 + 0x200/4;	// Points to 0x200 of PRU1 memory
+	prusharedMem_32int_ptr = pru + PRU_SHAREDMEM/4;	// Points to start of shared memory
+
+    uint32_t desired_duty_cycle = 0;
+    while (1) {
+        printf("Enter a duty cycle: ");
+        scanf("%d", &desired_duty_cycle);
+        start_pwm_count(desired_duty_cycle);
+    }
+	
+	if(munmap(pru, PRU_LEN)) {
+		printf("munmap failed\n");
+	} else {
+		printf("munmap succeeded\n");
+	}
+}