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Imants Pulkstenis
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/* --COPYRIGHT--,BSD_EX
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* Copyright (c) 2012, Texas Instruments Incorporated
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* All rights reserved.
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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 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 "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
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* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
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* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
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* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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*******************************************************************************
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*
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* MSP430 CODE EXAMPLE DISCLAIMER
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*
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* MSP430 code examples are self-contained low-level programs that typically
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* demonstrate a single peripheral function or device feature in a highly
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* concise manner. For this the code may rely on the device's power-on default
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* register values and settings such as the clock configuration and care must
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* be taken when combining code from several examples to avoid potential side
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* effects. Also see www.ti.com/grace for a GUI- and www.ti.com/msp430ware
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* for an API functional library-approach to peripheral configuration.
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*
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* --/COPYRIGHT--*/
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//******************************************************************************
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// MSP430F20xx Demo - DCO Calibration Constants Programmer
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//
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// NOTE: THIS CODE REPLACES THE TI FACTORY-PROGRAMMED DCO CALIBRATION
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// CONSTANTS LOCATED IN INFOA WITH NEW VALUES. USE ONLY IF THE ORIGINAL
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// CONSTANTS ACCIDENTALLY GOT CORRUPTED OR ERASED.
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//
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// Description: This code re-programs the F2xx DCO calibration constants.
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// A software FLL mechanism is used to set the DCO based on an external
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// 32kHz reference clock. After each calibration, the values from the
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// clock system are read out and stored in a temporary variable. The final
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// frequency the DCO is set to is 1MHz, and this frequency is also used
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// during Flash programming of the constants. The program end is indicated
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// by the blinking LED.
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// ACLK = LFXT1/8 = 32768/8, MCLK = SMCLK = target DCO
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// //* External watch crystal installed on XIN XOUT is required for ACLK *//
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//
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// MSP430F20xx
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// ---------------
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// /|\| XIN|-
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// | | | 32kHz
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// --|RST XOUT|-
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// | |
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// | P1.0|--> LED
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// | P1.4|--> SMLCK = target DCO
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//
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// A. Dannenberg
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// Texas Instruments Inc.
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// May 2007
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// Built with CCE Version: 3.2.0 and IAR Embedded Workbench Version: 3.42A
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//******************************************************************************
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#include <msp430.h>
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#define DELTA_1MHZ 244 // 244 x 4096Hz = 999.4Hz
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#define DELTA_8MHZ 1953 // 1953 x 4096Hz = 7.99MHz
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#define DELTA_12MHZ 2930 // 2930 x 4096Hz = 12.00MHz
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#define DELTA_16MHZ 3906 // 3906 x 4096Hz = 15.99MHz
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unsigned char CAL_DATA[8]; // Temp. storage for constants
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volatile unsigned int i;
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int j;
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char *Flash_ptrA; // Segment A pointer
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void Set_DCO(unsigned int Delta);
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int main(void)
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{
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WDTCTL = WDTPW + WDTHOLD; // Stop WDT
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for (i = 0; i < 0xfffe; i++); // Delay for XTAL stabilization
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P1OUT = 0x00; // Clear P1 output latches
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P1SEL = 0x10; // P1.4 SMCLK output
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P1DIR = 0x11; // P1.0,4 output
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j = 0; // Reset pointer
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Set_DCO(DELTA_16MHZ); // Set DCO and obtain constants
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CAL_DATA[j++] = DCOCTL;
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CAL_DATA[j++] = BCSCTL1;
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Set_DCO(DELTA_12MHZ); // Set DCO and obtain constants
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CAL_DATA[j++] = DCOCTL;
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CAL_DATA[j++] = BCSCTL1;
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Set_DCO(DELTA_8MHZ); // Set DCO and obtain constants
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CAL_DATA[j++] = DCOCTL;
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CAL_DATA[j++] = BCSCTL1;
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Set_DCO(DELTA_1MHZ); // Set DCO and obtain constants
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CAL_DATA[j++] = DCOCTL;
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CAL_DATA[j++] = BCSCTL1;
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Flash_ptrA = (char *)0x10C0; // Point to beginning of seg A
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FCTL2 = FWKEY + FSSEL0 + FN1; // MCLK/3 for Flash Timing Generator
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FCTL1 = FWKEY + ERASE; // Set Erase bit
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FCTL3 = FWKEY + LOCKA; // Clear LOCK & LOCKA bits
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*Flash_ptrA = 0x00; // Dummy write to erase Flash seg A
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FCTL1 = FWKEY + WRT; // Set WRT bit for write operation
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Flash_ptrA = (char *)0x10F8; // Point to beginning of cal consts
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for (j = 0; j < 8; j++)
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*Flash_ptrA++ = CAL_DATA[j]; // re-flash DCO calibration data
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FCTL1 = FWKEY; // Clear WRT bit
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FCTL3 = FWKEY + LOCKA + LOCK; // Set LOCK & LOCKA bit
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while (1)
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{
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P1OUT ^= 0x01; // Toggle LED
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for (i = 0; i < 0x4000; i++); // SW Delay
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}
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}
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void Set_DCO(unsigned int Delta) // Set DCO to selected frequency
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{
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unsigned int Compare, Oldcapture = 0;
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BCSCTL1 |= DIVA_3; // ACLK = LFXT1CLK/8
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TACCTL0 = CM_1 + CCIS_1 + CAP; // CAP, ACLK
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TACTL = TASSEL_2 + MC_2 + TACLR; // SMCLK, cont-mode, clear
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while (1)
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{
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while (!(CCIFG & TACCTL0)); // Wait until capture occured
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TACCTL0 &= ~CCIFG; // Capture occured, clear flag
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Compare = TACCR0; // Get current captured SMCLK
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Compare = Compare - Oldcapture; // SMCLK difference
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Oldcapture = TACCR0; // Save current captured SMCLK
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if (Delta == Compare)
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break; // If equal, leave "while(1)"
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else if (Delta < Compare)
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{
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DCOCTL--; // DCO is too fast, slow it down
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if (DCOCTL == 0xFF) // Did DCO roll under?
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if (BCSCTL1 & 0x0f)
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BCSCTL1--; // Select lower RSEL
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}
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else
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{
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DCOCTL++; // DCO is too slow, speed it up
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if (DCOCTL == 0x00) // Did DCO roll over?
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if ((BCSCTL1 & 0x0f) != 0x0f)
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BCSCTL1++; // Sel higher RSEL
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}
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}
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TACCTL0 = 0; // Stop TACCR0
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TACTL = 0; // Stop Timer_A
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BCSCTL1 &= ~DIVA_3; // ACLK = LFXT1CLK
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}
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