git.mutantstargoat.com Git - rpipulser/blob - pulser.c

   1 #include <stdio.h>
   2 #include <stdlib.h>
   3 #include <stdint.h>
   4 #include <assert.h>
   5 #include <unistd.h>
   6 #include <fcntl.h>
   7 #include <sys/mman.h>
   8
   9 #define IOBASEADDR              0x3f000000
  10 #define IOSIZE                  16777216
  11
  12 #define IOREGADDR(x)    ((x) | IOBASEADDR)
  13
  14 #define REG_GPFSEL0             *((volatile uint32_t*)IOREGADDR(0x200000))
  15 #define REG_GPFSEL1             *((volatile uint32_t*)IOREGADDR(0x200004))
  16 #define REG_GPFSEL2             *((volatile uint32_t*)IOREGADDR(0x200008))
  17 #define REG_GPSET0              *((volatile uint32_t*)IOREGADDR(0x20001c))
  18 #define REG_GPSET1              *((volatile uint32_t*)IOREGADDR(0x200020))
  19 #define REG_GPCLR0              *((volatile uint32_t*)IOREGADDR(0x200028))
  20 #define REG_GPCLR1              *((volatile uint32_t*)IOREGADDR(0x20002c))
  21
  22 #define FSEL_OUT(x)             (1 << (((x) % 10) * 3))
  23
  24 void print_usage(const char *argv0);
  25
  26 int npulses = 1;
  27 int freqhz = 1;
  28 int duty = 128; /* duty cycle 0-255 */
  29 int pin = 24;
  30
  31 int main(int argc, char **argv)
  32 {
  33         int i, fd;
  34         void *ptr;
  35         long ontime, offtime;
  36
  37         for(i=1; i<argc; i++) {
  38                 if(argv[i][0] == '-') {
  39                         if(argv[i][2] == 0) {
  40                                 switch(argv[i][1]) {
  41                                 case 'n':
  42                                         if(!argv[++i] || (npulses = atoi(argv[i])) < 1) {
  43                                                 fprintf(stderr, "-n must be followed by the number of pulses\n");
  44                                                 return 1;
  45                                         }
  46                                         break;
  47
  48                                 case 'f':
  49                                         if(!argv[++i] || (freqhz = atoi(argv[i])) < 1) {
  50                                                 fprintf(stderr, "-f must be followed by the pulse frequency\n");
  51                                                 return 1;
  52                                         }
  53                                         break;
  54
  55                                 case 'd':
  56                                         if(!argv[++i] || (duty = atoi(argv[i])) < 1 || duty >= 256) {
  57                                                 fprintf(stderr, "-d must be followed by the duty cycle: 1-255\n");
  58                                                 return 1;
  59                                         }
  60                                         break;
  61
  62                                 case 'h':
  63                                         print_usage(argv[0]);
  64                                         return 0;
  65
  66                                 default:
  67                                         fprintf(stderr, "invalid option: %s\n", argv[i]);
  68                                         print_usage(argv[0]);
  69                                         return 1;
  70                                 }
  71                         } else {
  72                                 fprintf(stderr, "invalid option: %s\n", argv[i]);
  73                                 print_usage(argv[0]);
  74                                 return 1;
  75                         }
  76                 } else {
  77                         fprintf(stderr, "unexpected argument: %s\n", argv[i]);
  78                         print_usage(argv[0]);
  79                         return 1;
  80                 }
  81         }
  82
  83
  84         if((fd = open("/dev/mem", O_RDWR)) == -1) {
  85                 perror("failed to open /dev/mem");
  86                 return 1;
  87         }
  88         if((ptr = mmap((void*)IOBASEADDR, IOSIZE, PROT_READ | PROT_WRITE,
  89                                         MAP_SHARED | MAP_FIXED, fd, IOBASEADDR)) == (void*)-1) {
  90                 perror("failed to map IO space");
  91                 return 1;
  92         }
  93         assert(ptr == (void*)IOBASEADDR);
  94
  95         ontime = duty * 1000000 / (freqhz * 256);
  96         offtime = 1000000 / freqhz - ontime;
  97
  98         printf("%d pulses, %d hz, %d/256 duty cycle\n", npulses, freqhz, duty);
  99         printf("timing: %ldus on, %ldus off\n", ontime, offtime);
 100
 101         REG_GPCLR0 = 1 << pin;
 102         if(pin < 10) {
 103                 REG_GPFSEL0 |= FSEL_OUT(pin);
 104         } else if(pin < 20) {
 105                 REG_GPFSEL1 |= FSEL_OUT(pin);
 106         } else if(pin < 30) {
 107                 REG_GPFSEL2 |= FSEL_OUT(pin);
 108         }
 109
 110         for(i=0; i<npulses; i++) {
 111                 REG_GPSET0 = 1 << pin;
 112                 usleep(ontime);
 113                 REG_GPCLR0 = 1 << pin;
 114                 usleep(offtime);
 115         }
 116
 117         REG_GPCLR0 = 1 << pin;
 118
 119         munmap(ptr, IOSIZE);
 120         close(fd);
 121         return 0;
 122 }
 123
 124 void print_usage(const char *argv0)
 125 {
 126         printf("Usage: %s [options]\n", argv0);
 127         printf("Options:\n");
 128         printf(" -n: number of pulses to emit (default: 1)\n");
 129         printf(" -f: frequency of pulses in hz (default: 1)\n");
 130         printf(" -d: duty cycle [1, 255] (default: 128)\n");
 131         printf(" -h: print usage and exit\n");
 132 }