From: John Tsiombikas <nuclear@mutantstargoat.com>
Date: Tue, 23 Jul 2019 16:38:24 +0000 (+0300)
Subject: initial commit
X-Git-Url: http://git.mutantstargoat.com/user/nuclear/?p=rpipulser;a=commitdiff_plain;h=e49ca3664591e457ffd8938ac4ecafd2f87e015b

initial commit
---

e49ca3664591e457ffd8938ac4ecafd2f87e015b
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..9d9159f
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,11 @@
+obj = pulser.o
+bin = pulser
+
+CFLAGS = -pedantic -Wall -g
+
+$(bin): $(obj)
+	$(CC) -o $@ $(obj) $(LDFLAGS)
+
+.PHONY: clean
+clean:
+	rm -f $(obj) $(bin)
diff --git a/pulser.c b/pulser.c
new file mode 100644
index 0000000..6362d67
--- /dev/null
+++ b/pulser.c
@@ -0,0 +1,132 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <assert.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/mman.h>
+
+#define IOBASEADDR		0x3f000000
+#define IOSIZE			16777216
+
+#define IOREGADDR(x)	((x) | IOBASEADDR)
+
+#define REG_GPFSEL0		*((volatile uint32_t*)IOREGADDR(0x200000))
+#define REG_GPFSEL1		*((volatile uint32_t*)IOREGADDR(0x200004))
+#define REG_GPFSEL2		*((volatile uint32_t*)IOREGADDR(0x200008))
+#define REG_GPSET0		*((volatile uint32_t*)IOREGADDR(0x20001c))
+#define REG_GPSET1		*((volatile uint32_t*)IOREGADDR(0x200020))
+#define REG_GPCLR0		*((volatile uint32_t*)IOREGADDR(0x200028))
+#define REG_GPCLR1		*((volatile uint32_t*)IOREGADDR(0x20002c))
+
+#define FSEL_OUT(x)		(1 << (((x) % 10) * 3))
+
+void print_usage(const char *argv0);
+
+int npulses = 1;
+int freqhz = 1;
+int duty = 128;	/* duty cycle 0-255 */
+int pin = 24;
+
+int main(int argc, char **argv)
+{
+	int i, fd;
+	void *ptr;
+	long ontime, offtime;
+
+	for(i=1; i<argc; i++) {
+		if(argv[i][0] == '-') {
+			if(argv[i][2] == 0) {
+				switch(argv[i][1]) {
+				case 'n':
+					if(!argv[++i] || (npulses = atoi(argv[i])) < 1) {
+						fprintf(stderr, "-n must be followed by the number of pulses\n");
+						return 1;
+					}
+					break;
+
+				case 'f':
+					if(!argv[++i] || (freqhz = atoi(argv[i])) < 1) {
+						fprintf(stderr, "-f must be followed by the pulse frequency\n");
+						return 1;
+					}
+					break;
+
+				case 'd':
+					if(!argv[++i] || (duty = atoi(argv[i])) < 1 || duty >= 256) {
+						fprintf(stderr, "-d must be followed by the duty cycle: 1-255\n");
+						return 1;
+					}
+					break;
+
+				case 'h':
+					print_usage(argv[0]);
+					return 0;
+
+				default:
+					fprintf(stderr, "invalid option: %s\n", argv[i]);
+					print_usage(argv[0]);
+					return 1;
+				}
+			} else {
+				fprintf(stderr, "invalid option: %s\n", argv[i]);
+				print_usage(argv[0]);
+				return 1;
+			}
+		} else {
+			fprintf(stderr, "unexpected argument: %s\n", argv[i]);
+			print_usage(argv[0]);
+			return 1;
+		}
+	}
+
+
+	if((fd = open("/dev/mem", O_RDWR)) == -1) {
+		perror("failed to open /dev/mem");
+		return 1;
+	}
+	if((ptr = mmap((void*)IOBASEADDR, IOSIZE, PROT_READ | PROT_WRITE,
+					MAP_SHARED | MAP_FIXED, fd, IOBASEADDR)) == (void*)-1) {
+		perror("failed to map IO space");
+		return 1;
+	}
+	assert(ptr == (void*)IOBASEADDR);
+
+	ontime = duty * 1000000 / (freqhz * 256);
+	offtime = 1000000 / freqhz - ontime;
+
+	printf("%d pulses, %d hz, %d/256 duty cycle\n", npulses, freqhz, duty);
+	printf("timing: %ldus on, %ldus off\n", ontime, offtime);
+
+	REG_GPCLR0 = 1 << pin;
+	if(pin < 10) {
+		REG_GPFSEL0 |= FSEL_OUT(pin);
+	} else if(pin < 20) {
+		REG_GPFSEL1 |= FSEL_OUT(pin);
+	} else if(pin < 30) {
+		REG_GPFSEL2 |= FSEL_OUT(pin);
+	}
+
+	for(i=0; i<npulses; i++) {
+		REG_GPSET0 = 1 << pin;
+		usleep(ontime);
+		REG_GPCLR0 = 1 << pin;
+		usleep(offtime);
+	}
+
+	REG_GPCLR0 = 1 << pin;
+
+	munmap(ptr, IOSIZE);
+	close(fd);
+	return 0;
+}
+
+void print_usage(const char *argv0)
+{
+	printf("Usage: %s [options]\n", argv0);
+	printf("Options:\n");
+	printf(" -n: number of pulses to emit (default: 1)\n");
+	printf(" -f: frequency of pulses in hz (default: 1)\n");
+	printf(" -d: duty cycle [1, 255] (default: 128)\n");
+	printf(" -h: print usage and exit\n");
+}