1 files changed, 146 insertions, 0 deletions
diff --git a/trasmitter/sender-chip.c b/trasmitter/sender-chip.c
new file mode 100644
index 0000000..7ada0cf
--- /dev/null
+++ b/trasmitter/sender-chip.c
@@ -0,0 +1,146 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <time.h>
+#include <sched.h>
+#include <inttypes.h>
+
+#define PIN "132"
+
+void init_pin() {
+  int fd = open("/sys/class/gpio/export",O_WRONLY);
+  char buf[16];
+  int len = sprintf(buf,"%s\n",PIN);
+  write(fd,buf,len);
+  close(fd);
+  fd = open("/sys/class/gpio/gpio" PIN "/direction",O_WRONLY);
+  write(fd,"out\n",4);
+  close(fd);
+}
+
+void deinit_pin() {
+  int fd = open("/sys/class/gpio/unexport",O_WRONLY);
+  char buf[16];
+  int len = sprintf(buf,"%s\n",PIN);
+  write(fd,buf,len);
+  close(fd);
+}
+
+int pin_fd;
+void write_pin(uint8_t value) {
+  if (!pin_fd) {
+    pin_fd = open("/sys/class/gpio/gpio" PIN "/value",O_WRONLY);
+  }
+  char buf[16];
+  int len = sprintf(buf,"%d\n",value);
+  write(pin_fd,buf,len);
+}
+
+void init_sched() {
+  struct sched_param sp;
+  sp.sched_priority=99;
+
+  // to make this work, sudo setcap CAP_SYS_NICE=eip clock
+  sched_setscheduler(0,SCHED_RR,&sp);
+}
+
+const int width=520000;
+struct timespec next_step;
+void send_array(const uint8_t values[],size_t len) {
+  if (next_step.tv_sec == 0) {
+    clock_gettime(CLOCK_REALTIME,&next_step);
+  }
+  uint8_t pin_value = 1;
+  for (int i=0; i<len; ++i) {
+    write_pin(pin_value);
+    pin_value = 1 - pin_value;
+
+    next_step.tv_nsec += width * values[i];
+
+    if (next_step.tv_nsec > 1000000000UL) {
+      next_step.tv_nsec -= 1000000000UL;
+      ++next_step.tv_sec;
+    }
+
+    int rc = clock_nanosleep(CLOCK_REALTIME,
+                             TIMER_ABSTIME,
+                             &next_step,
+                             NULL);
+    if (rc) {
+      printf("problems: %d\n",rc);
+    }
+  }
+}
+void my_sleep(uint8_t seconds) {
+  next_step.tv_sec += seconds;
+
+  int rc = clock_nanosleep(CLOCK_REALTIME,
+                           TIMER_ABSTIME,
+                           &next_step,
+                           NULL);
+  if (rc) {
+    printf("problems: %d\n",rc);
+  }
+}
+
+// alternate HIGH and LOW, first one of each array is HIGH
+const uint8_t prologue[] = {
+  1,1, 1,1, 1,1, 1,1, 1,1, 1,1,
+  2,3, 1,1, 2,2, 1,1, 1,1, 2,1,
+  1,1, 1,1, 1,2, 1,1, 1,1, 1,1,
+  1,1, 1,1,
+};
+const size_t prologueSize = sizeof(prologue) / sizeof(uint8_t);
+
+const uint8_t epilogue[] = {
+  1,2, 2,2, 1,3, // the last value doesn't much matter
+};
+const size_t epilogueSize = sizeof(epilogue) / sizeof(uint8_t);
+
+const uint8_t onSignal[] = {
+  2,2, 1,1, 1,1, 1,1, 1,1, 2,1, 1,1,
+};
+const size_t onSize = sizeof(onSignal) / sizeof(uint8_t);
+
+const uint8_t offSignal[] = {
+  1,1, 1,1, 1,1, 1,1, 1,1, 2,2, 2,1,
+};
+const size_t offSize = sizeof(offSignal) / sizeof(uint8_t);
+
+void transmitSignal(const uint8_t signal[], size_t signalSize) {
+  send_array(prologue,prologueSize);
+  send_array(signal,signalSize);
+  send_array(epilogue,epilogueSize);
+}
+
+void sendTrain(const uint8_t signal[], size_t signalSize) {
+  transmitSignal(offSignal,offSize);
+  my_sleep(1);
+  transmitSignal(signal,signalSize);
+  my_sleep(2);
+  transmitSignal(offSignal,offSize);
+}
+
+int main(int argc,char **argv) {
+  if (argc != 2) {
+    fprintf(stderr,"thing 0/1\n");
+    return 1;
+  }
+
+  init_sched();
+  init_pin();
+  write_pin(0);
+
+  if (argv[1][0] == '1') {
+    sendTrain(onSignal,onSize);
+  }
+  else {
+    sendTrain(offSignal,offSize);
+  }
+
+  deinit_pin();
+
+  return 0;
+}