+
+ /* process angle from laserdiff time */
+#ifdef SPEED_10RPS
+ /* timer = 2Mhz */
+ a = ((double)laserdiff / (2000000./10.)) * 2. * M_PI;
+#else
+ /* timer = 16Mhz */
+ a = ((double)laserdiff / (16000000./40.)) * 2. * M_PI;
+#endif
+ /* get distance from angle */
+ d = LASER_DIST / sin(a/2);
+
+ /* scale it between 0 and 511 */
+ if (d <= MIN_DIST)
+ return 0;
+ if (d >= MAX_DIST)
+ return 0;
+ d -= MIN_DIST;
+ d /= (MAX_DIST-MIN_DIST);
+ d *= 512;
+ frame_dist = (uint16_t)d;
+ if (frame_dist >= 512) /* should not happen... */
+ return 0;
+
+ frame |= ((uint32_t)(frame_dist & FRAME_DATA_MASK) << FRAME_DATA_SHIFT);
+
+ /* process cksum and return */
+ return do_cksum(frame);