From b02c3608efd1e842a457046d3a6f0d98db16371b Mon Sep 17 00:00:00 2001
From: Michael Oborne <mich146@hotmail.com>
Date: Thu, 13 Oct 2011 22:36:51 +0800
Subject: [PATCH] fix delta time in imu shim

---
 libraries/AP_IMU/AP_IMU_Shim.h | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/libraries/AP_IMU/AP_IMU_Shim.h b/libraries/AP_IMU/AP_IMU_Shim.h
index 57bf298414..4dea37330a 100644
--- a/libraries/AP_IMU/AP_IMU_Shim.h
+++ b/libraries/AP_IMU/AP_IMU_Shim.h
@@ -19,6 +19,13 @@ public:
 	virtual bool	update(void) {
 		bool updated = _updated;
 		_updated = false;
+        
+        // return number of microseconds since last call
+        uint32_t us = micros();
+        uint32_t ret = us - last_ch6_micros;
+        last_ch6_micros = us;
+        
+        _sample_time = ret;
 		return updated;
 	}
 	//@}
@@ -54,6 +61,7 @@ public:
 private:
 	/// set true when new data is delivered
 	bool		_updated;
+    uint32_t    last_ch6_micros;
 };
 
 #endif