Move to micronucleus assembly for OSCCAL calibration

[riso-kagaku-clone.git] / libs-device / osccal.h

diff --git a/libs-device/osccal.h b/libs-device/osccal.h
index 1ed600697ca7d1c8a02f2d584af549d4b70a711e..3452aa77e8c8b70a24df6647186c1c1c529827a1 100644 (file)
--- a/libs-device/osccal.h
+++ b/libs-device/osccal.h
@@ -1,5 +1,6 @@
 /* Name: osccal.h
  * Author: Christian Starkjohann
+ * Changes 2013-11-04 cpldcpu@gmail.com
  * Creation Date: 2008-04-10
  * Tabsize: 4
  * Copyright: (c) 2008 by OBJECTIVE DEVELOPMENT Software GmbH
@@ -13,28 +14,18 @@ oscillator so that the CPU runs at F_CPU (F_CPU is a macro which must be
 defined when the module is compiled, best passed in the compiler command
 line). The time reference is the USB frame clock of 1 kHz available
 immediately after a USB RESET condition. Timing is done by counting CPU
-cycles, so all interrupts must be disabled while the calibration runs. For
-low level timing measurements, usbMeasureFrameLength() is called. This
-function must be enabled in usbconfig.h by defining
-USB_CFG_HAVE_MEASURE_FRAME_LENGTH to 1. It is recommended to call
-calibrateOscillator() from the reset hook in usbconfig.h:
+cycles, so all interrupts must be disabled while the calibration runs.
+The size optimized assembler implementation includes its own implementation
+of usbMeasureFrameLength. Therefore USB_CFG_HAVE_MEASURE_FRAME_LENGTH should
+be set to 0 to avoid including unused code sections. It is recommended to call
+calibrateOscillatorASM() from the reset hook in usbconfig.h by including osccal.h:
 
-#ifndef __ASSEMBLER__
-#include <avr/interrupt.h>  // for sei()
-extern void calibrateOscillator(void);
-#endif
-#define USB_RESET_HOOK(resetStarts)  if(!resetStarts){cli(); calibrateOscillator(); sei();}
+#include "osccal.h"
 
 This routine is an alternative to the continuous synchronization described
 in osctune.h.
 
-Algorithm used:
-calibrateOscillator() first does a binary search in the OSCCAL register for
-the best matching oscillator frequency. Then it does a next neighbor search
-to find the value with the lowest clock rate deviation. It is guaranteed to
-find the best match among neighboring values, but for version 5 oscillators
-(which have a discontinuous relationship between OSCCAL and frequency) a
-better match might be available in another OSCCAL region.
+Algorithm used: see osccalASM.S
 
 Limitations:
 This calibration algorithm may try OSCCAL values of up to 192 even if the
@@ -50,7 +41,10 @@ deviation! All other frequency modules require at least 0.2% precision.
 #ifndef __OSCCAL_H_INCLUDED__
 #define __OSCCAL_H_INCLUDED__
 
-void    calibrateOscillator(void);
+#ifndef __ASSEMBLER__
+void    calibrateOscillatorASM(void);
+#define USB_RESET_HOOK(resetStarts)  if(!resetStarts){ calibrateOscillatorASM();}
+#endif
 /* This function calibrates the RC oscillator so that the CPU runs at F_CPU.
  * It MUST be called immediately after the end of a USB RESET condition!
  * Disable all interrupts during the call!