altos: Switch beeping to farnsworth spacing

[fw/altos] / src / kernel / ao_report.c

diff --git a/src/kernel/ao_report.c b/src/kernel/ao_report.c
index 1104cd82532ff8173334591ee06c534b968e1f42..f22631547473d7de341bff5c91d85107ec8d133f 100644 (file)
--- a/src/kernel/ao_report.c
+++ b/src/kernel/ao_report.c
@@ -52,6 +52,60 @@ static const uint8_t flight_reports[] = {
 
 static __pdata enum ao_flight_state ao_report_state;
 
+/*
+ * Farnsworth spacing
+ *
+ * From: http://www.arrl.org/files/file/Technology/x9004008.pdf
+ *
+ *     c:      character rate in wpm
+ *     s:      overall rate in wpm
+ *     u:      unit rate (dit speed)
+ *
+ *     dit:                    u
+ *     dah:                    3u
+ *     intra-character-time:   u
+ *
+ *     u = 1.2/c
+ *
+ * Because our clock runs at 10ms, we'll round up to 70ms for u, which
+ * is about 17wpm
+ *
+ *     Farnsworth adds space between characters and
+ *     words:
+ *           60 c - 37.2 s
+ *     Ta = -------------
+ *                sc
+ *
+ *           3 Ta
+ *     Tc = ----
+ *            19
+ *
+ *           7 Ta
+ *     Tw = ----
+ *            19
+ *
+ *     Ta = total delay to add to the characters (31 units)
+ *           of a standard 50-unit "word", in seconds
+ *
+ *      Tc = period between characters, in seconds
+ *
+ *     Tw = period between words, in seconds
+ *
+ * We'll use Farnsworth spacing with c=18 and s=12:
+ *
+ *     u = 1.2/18 = 0.0667
+ *
+ *     Ta = (60 * 17 - 37.2 * 12) / (17 * 12) = 2.812
+ *
+ *     Tc = 3 * Ta / 19 = .444
+ *
+ *     Tw = 1.036
+ *
+ * Note that the values below are all reduced by 10ms; that's because
+ * the timer always adds a tick to make sure the task actually sleeps
+ * at least as long as the argument.
+ */
+
 static void
 ao_report_beep(void) __reentrant
 {
@@ -62,13 +116,13 @@ ao_report_beep(void) __reentrant
                return;
        while (l--) {
                if (r & 8)
-                       mid(AO_MS_TO_TICKS(600));
-               else
                        mid(AO_MS_TO_TICKS(200));
-               pause(AO_MS_TO_TICKS(200));
+               else
+                       mid(AO_MS_TO_TICKS(60));
+               pause(AO_MS_TO_TICKS(60));
                r >>= 1;
        }
-       pause(AO_MS_TO_TICKS(400));
+       pause(AO_MS_TO_TICKS(360));
 }
 
 static void
@@ -87,19 +141,18 @@ ao_report_digit(uint8_t digit) __reentrant
 }
 
 static void
-ao_report_altitude(void)
+ao_report_number(int16_t n)
 {
-       __pdata int16_t agl = ao_max_height;
        __xdata uint8_t digits[10];
        __pdata uint8_t ndigits, i;
 
-       if (agl < 0)
-               agl = 0;
+       if (n < 0)
+               n = 0;
        ndigits = 0;
        do {
-               digits[ndigits++] = agl % 10;
-               agl /= 10;
-       } while (agl);
+               digits[ndigits++] = n % 10;
+               n /= 10;
+       } while (n);
 
        i = ndigits;
        do
@@ -107,6 +160,27 @@ ao_report_altitude(void)
        while (i != 0);
 }
 
+static void
+ao_report_altitude(void)
+{
+       ao_report_number(ao_max_height);
+}
+
+#if HAS_BATTERY_REPORT
+static void
+ao_report_battery(void)
+{
+       __xdata struct ao_data packet;
+       for (;;) {
+               ao_data_get(&packet);
+               if (packet.adc.v_batt != 0)
+                       break;
+               ao_sleep(DATA_TO_XDATA(&ao_sample_data));
+       }
+       ao_report_number(ao_battery_decivolt(packet.adc.v_batt));
+}
+#endif
+
 #if HAS_IGNITE_REPORT
 static uint8_t
 ao_report_igniter_ready(enum ao_igniter igniter)
@@ -163,7 +237,12 @@ ao_report(void)
 {
        ao_report_state = ao_flight_state;
        for(;;) {
-               ao_report_beep();
+#if HAS_BATTERY_REPORT
+               if (ao_flight_state == ao_flight_startup)
+                       ao_report_battery();
+               else
+#endif
+                       ao_report_beep();
                if (ao_flight_state == ao_flight_landed) {
                        ao_report_altitude();
 #if HAS_FLIGHT