154 lines
5.0 KiB
C
154 lines
5.0 KiB
C
//###########################################################################
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//
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// FILE: Example_freqcal.h
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//
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// TITLE: Frequency measurement using EQEP peripheral
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//
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// DESCRIPTION: Header file containing data type and object definitions and
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// initializers.
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//
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//###########################################################################
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// $TI Release: $
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// $Release Date: $
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// $Copyright:
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// Copyright (C) 2009-2023 Texas Instruments Incorporated - http://www.ti.com/
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//
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// Redistribution and use in source and binary forms, with or without
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// modification, are permitted provided that the following conditions
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// are met:
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//
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// Redistributions of source code must retain the above copyright
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// notice, this list of conditions and the following disclaimer.
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//
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// Redistributions in binary form must reproduce the above copyright
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// notice, this list of conditions and the following disclaimer in the
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// documentation and/or other materials provided with the
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// distribution.
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//
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// Neither the name of Texas Instruments Incorporated nor the names of
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// its contributors may be used to endorse or promote products derived
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// from this software without specific prior written permission.
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//
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// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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// $
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//###########################################################################
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#ifndef __FREQCAL__
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#define __FREQCAL__
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//
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// Included Files
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//
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#include "IQmathLib.h" // Include header for IQmath library
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//
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// Typedef structure of the FREQCAL Object
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//
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typedef struct
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{
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//
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// Scaler converting 1/N cycles to a GLOBAL_Q freq (Q0)
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// independently with global Q
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//
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Uint32 freqScaler_pr;
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//
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// Scaler converting 1/N cycles to a GLOBAL_Q freq (Q0)
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// independently with global Q
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//
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Uint32 freqScaler_fr;
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Uint32 BaseFreq; // Parameter : Maximum Freq
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_iq freq_pr; // Output : Freq in per-unit using capture unit
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int32 freqhz_pr; // Output: Freq in Hz, measured using Capture unit
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Uint32 oldpos;
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_iq freq_fr; // Output : Freq in per-unit using position counter
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int32 freqhz_fr; // Output: Freq in Hz, measured using Capture unit
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void (*init)(); // Pointer to the init function
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void (*calc)(); // Pointer to the calc function
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} FREQCAL;
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//
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// Define for a QEP_handle
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//
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typedef FREQCAL *FREQCAL_handle;
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//
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// Default initializer for the FREQCAL Object
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//
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#if (CPU_FRQ_150MHZ)
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#define FREQCAL_DEFAULTS {\
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234,200,10000,0,0,\
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0,0,0,\
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(void (*)(long))FREQCAL_Init,\
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(void (*)(long))FREQCAL_Calc }
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#endif
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#if (CPU_FRQ_100MHZ)
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#define FREQCAL_DEFAULTS {\
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313,200,10000,0,0,\
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0,0,0,\
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(void (*)(long))FREQCAL_Init,\
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(void (*)(long))FREQCAL_Calc }
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#endif
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//
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// Function Prototypes
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//
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void FREQCAL_Init(void);
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void FREQCAL_Calc(FREQCAL_handle);
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#endif /* __FREQCAL__ */
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//
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// For 150 MHz Operation:
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//
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// 1. freqScaler_fr
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// v = (x2-x1)/T - Equation 1
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//
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// If max/base freq = 10kHz: 10kHz = (x2-x1)/(2/100Hz) - Equation 2
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// max (x2-x1) = 200 counts = freqScaler_fr
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// Note: T = 2/100Hz. 2 is from (x2-x1)/2 - because QPOSCNT counts
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// 2 edges per cycle (rising and falling)
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// freqhz_fr = 200 default
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//
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// 2. min freq = 1 count/(2/100Hz) = 50 Hz
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//
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// 3. freqScaler_pr
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// v = X/(t2-t1) - Equation 4
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//
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// If max/base freq = 10kHz: 10kHz = 8/(2T)
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// where 4 = QCAPCTL [UPPS] (Unit timeout - once every 4 edges)
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// T = time in seconds = t2-t1/(150MHz/128),
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// t2-t1= # of QCAPCLK cycles, and
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// 1 QCAPCLK cycle = 1/(150MHz/128) = QCPRDLAT
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//
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// So: 10 kHz = 4(150MHz/128)/2(t2-t1)
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// Equation 5
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// t2-t1 = 4(150MHz/128)/(10kHz*2) = (150MHz/128)/(2*10kHz/4)
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// = 234 seconds = maximum (t2-t1) = freqScaler_pr
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// freqhz_pr = 234 default
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//
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//
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// For 100 MHz Operation:
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//
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// The same calculations as above are performed, but with 100 MHz
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// instead of 150MHz when calculation freqhr_pr, and at UPPS of 8 instead
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// of 4. The value for freqScaler_pr becomes: (100MHz/128)/(2*10kHz/8) = 313
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// More detailed calculation results can be found in the Example_freqcal.xls
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// spreadsheet included in the example folder.
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//
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//
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// End of File
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//
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