X-Git-Url: https://www.fi.muni.cz/~kas/git//home/kas/public_html/git/?a=blobdiff_plain;f=firmware%2Ffirmware.c;h=5400714f48b10645dc196673493eb88d7a321871;hb=0bbaad8dc171999d4aeabae9b5b222364f066388;hp=bbba9874c0231bf0467e01c249495dc264e52b9d;hpb=2f5956f3e324eb12fa3c20f0f4383a1e745bbe78;p=openparking.git

diff --git a/firmware/firmware.c b/firmware/firmware.c
index bbba987..5400714 100644
--- a/firmware/firmware.c
+++ b/firmware/firmware.c
@@ -5,8 +5,9 @@
 #include "clock.h"
 #include "modbus.h"
 
-#define ECHO_TIMEOUT		(CLOCK_HZ/10)	// 10 ms
-#define MEASUREMENT_WAIT	(CLOCK_HZ/3)	// three triggers per second
+#define ECHO_TIMEOUT		(CLOCK_HZ/10)	// 100 ms
+#define MEASUREMENT_WAIT	(2*ECHO_TIMEOUT)
+#define MEASUREMENT_SHIFT	0		// running avg (1 << M_SHIFT)
 
 #define N_TRIGGERS 3
 #define N_SENSORS 12
@@ -23,6 +24,7 @@
 #define distances	(hold_regs+MB_N_HOLD_REGS_EEPROM+1)
 #define free_bitmap	(hold_regs[MB_N_HOLD_REGS_EEPROM+13])
 #define err_bitmap	(hold_regs[MB_N_HOLD_REGS_EEPROM+14])
+#define max_distances	(hold_regs+MB_N_HOLD_REGS_EEPROM+21)
 
 static void pull_trigger(uint8_t trig)
 {
@@ -70,10 +72,33 @@ static void do_measurement(unsigned char trig)
 				to_start &= ~mask;
 				to_measure |= mask;
 			} else if ((to_measure & mask) && !(bits & mask)) {
+#if MEASUREMENT_SHIFT > 0
+				uint16_t old_d;
+#endif
+				uint16_t new_d;
+				uint8_t idx = trig*N_TRIG_SENSORS+i;
 				// echo end
 				to_measure &= ~mask;
-				distances[trig*N_TRIG_SENSORS + i]
-					= now - starttimes[i];
+				new_d = now - starttimes[i];
+				if (new_d > max_distances[idx])
+					max_distances[idx] = new_d;
+
+#if MEASUREMENT_SHIFT > 0
+				old_d = distances[idx];
+
+				if (old_d == 0
+					|| old_d == -1) {
+					distances[idx] = new_d;
+				} else {
+					distances[idx] = (
+						(old_d << MEASUREMENT_SHIFT)
+						+ new_d
+						- old_d
+						) >> MEASUREMENT_SHIFT;
+				}
+#else
+				distances[idx] = new_d;
+#endif
 			}
 		}
 	}