Move to micronucleus assembly for OSCCAL calibration

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

diff --git a/libs-device/osccal.c b/libs-device/osccal.c
deleted file mode 100644 (file)
index 61ae783..0000000
--- a/libs-device/osccal.c
+++ /dev/null
@@ -1,64 +0,0 @@
-/* Name: osccal.c
- * Author: Christian Starkjohann
- * Creation Date: 2008-04-10
- * Tabsize: 4
- * Copyright: (c) 2008 by OBJECTIVE DEVELOPMENT Software GmbH
- * License: GNU GPL v2 (see License.txt), GNU GPL v3 or proprietary (CommercialLicense.txt)
- */
-
-#include <avr/io.h>
-
-#include "usbdrv.h"
-
-#ifndef uchar
-#define uchar   unsigned char
-#endif
-
-/* ------------------------------------------------------------------------- */
-/* ------------------------ Oscillator Calibration ------------------------- */
-/* ------------------------------------------------------------------------- */
-
-/* Calibrate the RC oscillator. Our timing reference is the Start Of Frame
- * signal (a single SE0 bit) repeating every millisecond immediately after
- * a USB RESET. We first do a binary search for the OSCCAL value and then
- * optimize this value with a neighboorhod search.
- */
-void    calibrateOscillator(void)
-{
-uchar       step = 128;
-uchar       trialValue = 0, optimumValue;
-int         x, optimumDev, targetValue = (unsigned)(1499 * (double)F_CPU / 10.5e6 + 0.5);
-
-    /* do a binary search: */
-    do{
-        OSCCAL = trialValue + step;
-        x = usbMeasureFrameLength();    /* proportional to current real frequency */
-        if(x < targetValue)             /* frequency still too low */
-            trialValue += step;
-        step >>= 1;
-    }while(step > 0);
-    /* We have a precision of +/- 1 for optimum OSCCAL here */
-    /* now do a neighborhood search for optimum value */
-    optimumValue = trialValue;
-    optimumDev = x; /* this is certainly far away from optimum */
-    for(OSCCAL = trialValue - 1; OSCCAL <= trialValue + 1; OSCCAL++){
-        x = usbMeasureFrameLength() - targetValue;
-        if(x < 0)
-            x = -x;
-        if(x < optimumDev){
-            optimumDev = x;
-            optimumValue = OSCCAL;
-        }
-    }
-    OSCCAL = optimumValue;
-}
-/*
-Note: This calibration algorithm may try OSCCAL values of up to 192 even if
-the optimum value is far below 192. It may therefore exceed the allowed clock
-frequency of the CPU in low voltage designs!
-You may replace this search algorithm with any other algorithm you like if
-you have additional constraints such as a maximum CPU clock.
-For version 5.x RC oscillators (those with a split range of 2x128 steps, e.g.
-ATTiny25, ATTiny45, ATTiny85), it may be useful to search for the optimum in
-both regions.
-*/