From 55f755ed3b97525b29a16e02a1ebda7e12980f56 Mon Sep 17 00:00:00 2001
From: Pavel Semerad <semeradp@gmail.com>
Date: Mon, 14 May 2012 00:35:49 +0200
Subject: [PATCH] repair servo speed to not be dependent on ppm frame length

---
 ChangeLog |  2 ++
 calc.c    |  6 +++---
 ppm.c     | 13 +++++++------
 ppm.h     |  1 +
 4 files changed, 13 insertions(+), 9 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 3d70cc9..e8a0236 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,6 +1,8 @@
 *0.6.1 ()
     repaired ABS to use cycle length same as before PPM frame length changes
     added extra brake channel for throttle brake side
+    repaired steering/throttle/channel speed to not beeing dependent
+	on ppm frame length
 
 *0.6.0 (28 Apr 2012)
     increased model memories by using FLASH also
diff --git a/calc.c b/calc.c
index 094617a..56479ac 100644
--- a/calc.c
+++ b/calc.c
@@ -186,7 +186,7 @@ static s16 steering_speed(s16 val, u8 channel) {
 
     // calculate max delta
     if (stspd == 100)  max_delta = PPM(1000);
-    else  max_delta = PPM(1000) / 2 / (100 - stspd);
+    else  max_delta = PPM(1000) / 2 / 20 * ppm_frame_length / (100 - stspd);
 
     // compare delta with max_delta
     if (delta < 0) {
@@ -207,7 +207,7 @@ static s16 steering_speed(s16 val, u8 channel) {
     // check if it is moving from return to turn
     if (delta2) {
 	if (cm.stspd_turn == 100)  max_delta = PPM(1000);
-	else  max_delta = PPM(1000) / 2 / (100 - cm.stspd_turn);
+	else  max_delta = PPM(1000) / 2 / 20 * ppm_frame_length / (100 - cm.stspd_turn);
 
 	if (delta2 < 0) {
 	    if (max_delta < -delta2)  val = -max_delta;
@@ -245,7 +245,7 @@ static s16 channel_speed(s16 val, u8 channel) {
 	}
     }
 
-    max_delta = PPM(1000) / 2 / (100 - speed);
+    max_delta = PPM(1000) / 2 / 20 * ppm_frame_length / (100 - speed);
     if (delta < 0) {
 	if (max_delta < -delta)  val = last - max_delta;
     }
diff --git a/ppm.c b/ppm.c
index 2836924..2d444a3 100644
--- a/ppm.c
+++ b/ppm.c
@@ -57,6 +57,7 @@ u8 ppm_timer;			// timer incremented every 1ms
 u8 ppm_start;			// when to start servo pulses
 u8 ppm_end;			// when must last PPM frame end (to not start again before)
 u8 ppm_calc_awake;		// when to awake CALC task
+u8 ppm_frame_length;		// last length of ppm frame
 
 
 
@@ -172,19 +173,19 @@ void ppm_calc_sync(void) {
     ppm_calc_len -= ppm_calc_awake;
     ppm_calc_len++;
 
-    // calculate new ppm_end
-    ppm_end = (u8)((ppm_microsecs01 + 9999) / 10000);
+    // calculate frame length and new ppm_end
+    ppm_frame_length = (u8)((ppm_microsecs01 + 9999) / 10000);
     if (cg.ppm_sync_frame) {
 	// constant frame length
 	u8 fl = (u8)(cg.ppm_length + 9);
-	ppm_end += PPM_SYNC_LENGTH_MIN;		// minimal frame with SYNC signal
-	if (ppm_end < fl)  ppm_end = fl;
+	ppm_frame_length += PPM_SYNC_LENGTH_MIN;	// minimal frame with SYNC signal
+	if (ppm_frame_length < fl)  ppm_frame_length = fl;
     }
     else {
 	// constant sync length
-	ppm_end += (u8)(cg.ppm_length + 3);
+	ppm_frame_length += (u8)(cg.ppm_length + 3);
     }
-    ppm_end += ppm_start;
+    ppm_end = (u8)(ppm_start + ppm_frame_length);
     ppm_microsecs01 = 0;
 
     // set new ppm_calc_awake
diff --git a/ppm.h b/ppm.h
index 26611a0..ffd2bb1 100644
--- a/ppm.h
+++ b/ppm.h
@@ -48,6 +48,7 @@ extern u8 ppm_values[];		// as bytes for ppm_interrupt and timer_interrupt
 extern u8 ppm_timer;		// timer incremented every 1ms
 extern u8 ppm_start;		// when to start servo pulses
 extern u8 ppm_calc_awake;	// when to awake CALC task
+extern u8 ppm_frame_length;	// last length of ppm frame
 
 // set actual number of channels
 extern void ppm_set_channels(u8 n);