crc7.c 3.2 KB

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  1. /* This file is a modified version of the output of pycrc.
  2. *
  3. * Licensing terms of pycrc:
  4. *
  5. * Copyright (c) 2006-2007, Thomas Pircher <tehpeh@gmx.net>
  6. *
  7. * Permission is hereby granted, free of charge, to any person obtaining a copy
  8. * of this software and associated documentation files (the "Software"), to deal
  9. * in the Software without restriction, including without limitation the rights
  10. * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  11. * copies of the Software, and to permit persons to whom the Software is
  12. * furnished to do so, subject to the following conditions:
  13. *
  14. * The above copyright notice and this permission notice shall be included in
  15. * all copies or substantial portions of the Software.
  16. *
  17. * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  18. * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  19. * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  20. * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  21. * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  22. * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  23. * THE SOFTWARE.
  24. *
  25. *
  26. * crc7.c: Calculate CRC7 for SD card commands
  27. *
  28. */
  29. /*
  30. * Functions and types for CRC checks.
  31. *
  32. * Generated on Thu Nov 8 13:52:05 2007,
  33. * by pycrc v0.6.3, http://www.tty1.net/pycrc/
  34. * using the configuration:
  35. * Width = 7
  36. * Poly = 0x09
  37. * XorIn = 0x00
  38. * ReflectIn = False
  39. * XorOut = 0x00
  40. * ReflectOut = False
  41. * Algorithm = bit-by-bit-fast
  42. */
  43. #include <stdint.h>
  44. #include <stdlib.h>
  45. #include <stdbool.h>
  46. /**
  47. ; MMC/SD CRC Polynom X^7 + X^3 + 1
  48. crc7taba:
  49. mov dptr,#CRC7_TABA ; (2)
  50. clr c ; (1)
  51. rrc a ; (1)
  52. xrl a,crc7ta ; (1)
  53. movc a,@a+dptr ; (2)
  54. jnc crc7m ; (2)
  55. xrl a,#00001001b ; (1)
  56. crc7m: mov crc7ta,a ; (1)
  57. ret ; (2) (LCALL=2)
  58. */
  59. uint8_t crc7tab[128] = {
  60. 0x00,0x12,0x24,0x36,0x48,0x5a,0x6c,0x7e,
  61. 0x19,0x0b,0x3d,0x2f,0x51,0x43,0x75,0x67,
  62. 0x32,0x20,0x16,0x04,0x7a,0x68,0x5e,0x4c,
  63. 0x2b,0x39,0x0f,0x1d,0x63,0x71,0x47,0x55,
  64. 0x64,0x76,0x40,0x52,0x2c,0x3e,0x08,0x1a,
  65. 0x7d,0x6f,0x59,0x4b,0x35,0x27,0x11,0x03,
  66. 0x56,0x44,0x72,0x60,0x1e,0x0c,0x3a,0x28,
  67. 0x4f,0x5d,0x6b,0x79,0x07,0x15,0x23,0x31,
  68. 0x41,0x53,0x65,0x77,0x09,0x1b,0x2d,0x3f,
  69. 0x58,0x4a,0x7c,0x6e,0x10,0x02,0x34,0x26,
  70. 0x73,0x61,0x57,0x45,0x3b,0x29,0x1f,0x0d,
  71. 0x6a,0x78,0x4e,0x5c,0x22,0x30,0x06,0x14,
  72. 0x25,0x37,0x01,0x13,0x6d,0x7f,0x49,0x5b,
  73. 0x3c,0x2e,0x18,0x0a,0x74,0x66,0x50,0x42,
  74. 0x17,0x05,0x33,0x21,0x5f,0x4d,0x7b,0x69,
  75. 0x0e,0x1c,0x2a,0x38,0x46,0x54,0x62,0x70
  76. };
  77. uint8_t crc7update(uint8_t crc, const uint8_t data) {
  78. uint8_t a = data;
  79. uint8_t b = data & 1;
  80. a = crc7tab[(a>>1) ^ crc];
  81. a ^= ((b<<3)|(b));
  82. crc = a;
  83. return a;
  84. }
  85. /*uint8_t crc7update(uint8_t crc, const uint8_t data) {
  86. uint8_t i;
  87. bool bit;
  88. uint8_t c;
  89. c = data;
  90. for (i = 0x80; i > 0; i >>= 1) {
  91. bit = crc & 0x40;
  92. if (c & i) {
  93. bit = !bit;
  94. }
  95. crc <<= 1;
  96. if (bit) {
  97. crc ^= 0x09;
  98. }
  99. }
  100. crc &= 0x7f;
  101. return crc & 0x7f;
  102. }*/