1 | //******************************************************************************
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2 | // MSP430F22x4 Demo - DCO Calibration Constants Programmer
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3 | //
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4 | //
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5 | // MSP430F22x4
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6 | // ---------------
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7 | // /|\| XIN|-
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8 | // | | | 32kHz
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9 | // --|RST XOUT|-
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10 | // | |
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11 | // | P1.0|--> LED
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12 | // | P2.1|--> SMLCK = target DCO
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13 | //
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14 | // A. Dannenberg
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15 | // Texas Instruments Inc.
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16 | // April 2006
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17 | // Built with CCE Version: 3.2.0 and IAR Embedded Workbench Version: 3.41A
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18 | //******************************************************************************
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19 | #include "msp430x22x4.h"
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20 |
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21 | #define DELTA_1MHZ 244 // 244 x 4096Hz = 999.4Hz
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22 | #define DELTA_8MHZ 1953 // 1953 x 4096Hz = 7.99MHz
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23 | #define DELTA_12MHZ 2930 // 2930 x 4096Hz = 12.00MHz
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24 | #define DELTA_16MHZ 3906 // 3906 x 4096Hz = 15.99MHz
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25 |
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26 | unsigned char CAL_DATA[8]; // Temp. storage for constants
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27 | volatile unsigned int i;
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28 | int j;
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29 | char *Flash_ptrA; // Segment A pointer
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30 | void Set_DCO(unsigned int Delta);
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31 |
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32 | void main(void)
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33 | {
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34 | WDTCTL = WDTPW + WDTHOLD; // Stop WDT
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35 | for (i = 0; i < 0xfffe; i++); // Delay for XTAL stabilization
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36 | P1OUT = 0x00; // Clear P1 output latches
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37 | P1DIR = 0x01; // P1.0 output
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38 | P2SEL |= 0x06; // P2.1 SMCLK output, P2.2 CCI0B input
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39 | P2DIR |= 0x02; // P2.1 output
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40 |
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41 | j = 0; // Reset pointer
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42 |
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43 | Set_DCO(DELTA_16MHZ); // Set DCO and obtain constants
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44 | CAL_DATA[j++] = DCOCTL;
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45 | CAL_DATA[j++] = BCSCTL1;
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46 |
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47 | Set_DCO(DELTA_12MHZ); // Set DCO and obtain constants
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48 | CAL_DATA[j++] = DCOCTL;
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49 | CAL_DATA[j++] = BCSCTL1;
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50 |
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51 | Set_DCO(DELTA_8MHZ); // Set DCO and obtain constants
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52 | CAL_DATA[j++] = DCOCTL;
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53 | CAL_DATA[j++] = BCSCTL1;
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54 |
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55 | Set_DCO(DELTA_1MHZ); // Set DCO and obtain constants
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56 | CAL_DATA[j++] = DCOCTL;
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57 | CAL_DATA[j++] = BCSCTL1;
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58 |
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59 | Flash_ptrA = (char *)0x10C0; // Point to beginning of seg A
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60 | FCTL2 = FWKEY + FSSEL0 + FN1; // MCLK/3 for Flash Timing Generator
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61 | FCTL1 = FWKEY + ERASE; // Set Erase bit
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62 | FCTL3 = FWKEY + LOCKA; // Clear LOCK & LOCKA bits
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63 | *Flash_ptrA = 0x00; // Dummy write to erase Flash seg A
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64 | FCTL1 = FWKEY + WRT; // Set WRT bit for write operation
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65 | Flash_ptrA = (char *)0x10F8; // Point to beginning of cal consts
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66 | for (j = 0; j < 8; j++)
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67 | *Flash_ptrA++ = CAL_DATA[j]; // re-flash DCO calibration data
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68 | FCTL1 = FWKEY; // Clear WRT bit
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69 | FCTL3 = FWKEY + LOCKA + LOCK; // Set LOCK & LOCKA bit
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70 |
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71 | while (1)
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72 | {
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73 | P1OUT ^= 0x01; // Toggle LED
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74 | for (i = 0; i < 0x4000; i++); // SW Delay
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75 | }
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76 | }
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77 |
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78 | void Set_DCO(unsigned int Delta) // Set DCO to selected frequency
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79 | {
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80 | unsigned int Compare, Oldcapture = 0;
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81 |
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82 | BCSCTL1 |= DIVA_3; // ACLK = LFXT1CLK/8
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83 | TACCTL2 = CM_1 + CCIS_1 + CAP; // CAP, ACLK
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84 | TACTL = TASSEL_2 + MC_2 + TACLR; // SMCLK, cont-mode, clear
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85 |
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86 | while (1)
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87 | {
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88 | while (!(CCIFG & TACCTL2)); // Wait until capture occured
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89 | TACCTL2 &= ~CCIFG; // Capture occured, clear flag
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90 | Compare = TACCR2; // Get current captured SMCLK
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91 | Compare = Compare - Oldcapture; // SMCLK difference
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92 | Oldcapture = TACCR2; // Save current captured SMCLK
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93 |
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94 | if (Delta == Compare)
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95 | break; // If equal, leave "while(1)"
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96 | else if (Delta < Compare)
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97 | {
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98 | DCOCTL--; // DCO is too fast, slow it down
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99 | if (DCOCTL == 0xFF) // Did DCO roll under?
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100 | if (BCSCTL1 & 0x0f)
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101 | BCSCTL1--; // Select lower RSEL
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102 | }
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103 | else
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104 | {
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105 | DCOCTL++; // DCO is too slow, speed it up
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106 | if (DCOCTL == 0x00) // Did DCO roll over?
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107 | if ((BCSCTL1 & 0x0f) != 0x0f)
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108 | BCSCTL1++; // Sel higher RSEL
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109 | }
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110 | }
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111 | TACCTL2 = 0; // Stop TACCR2
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112 | TACTL = 0; // Stop Timer_A
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113 | BCSCTL1 &= ~DIVA_3; // ACLK = LFXT1CLK
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114 | }
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