bmp085.c 4.9 KB

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  1. #include "module.h"
  2. #include "lauxlib.h"
  3. #include "platform.h"
  4. #include "user_interface.h"
  5. #include <stdlib.h>
  6. #include <string.h>
  7. static const uint32_t bmp085_i2c_id = 0;
  8. static const uint8_t bmp085_i2c_addr = 0x77;
  9. static struct {
  10. int16_t AC1;
  11. int16_t AC2;
  12. int16_t AC3;
  13. uint16_t AC4;
  14. uint16_t AC5;
  15. uint16_t AC6;
  16. int16_t B1;
  17. int16_t B2;
  18. int16_t MB;
  19. int16_t MC;
  20. int16_t MD;
  21. } bmp085_data;
  22. static uint8_t r8u(uint32_t id, uint8_t reg) {
  23. uint8_t ret;
  24. platform_i2c_send_start(id);
  25. platform_i2c_send_address(id, bmp085_i2c_addr, PLATFORM_I2C_DIRECTION_TRANSMITTER);
  26. platform_i2c_send_byte(id, reg);
  27. platform_i2c_send_stop(id);
  28. platform_i2c_send_start(id);
  29. platform_i2c_send_address(id, bmp085_i2c_addr, PLATFORM_I2C_DIRECTION_RECEIVER);
  30. ret = platform_i2c_recv_byte(id, 0);
  31. platform_i2c_send_stop(id);
  32. return ret;
  33. }
  34. static uint16_t r16u(uint32_t id, uint8_t reg) {
  35. uint8_t high = r8u(id, reg);
  36. uint8_t low = r8u(id, reg + 1);
  37. return (high << 8) | low;
  38. }
  39. static int16_t r16(uint32_t id, uint8_t reg) {
  40. return (int16_t) r16u(id, reg);
  41. }
  42. static int bmp085_setup(lua_State* L) {
  43. (void)L;
  44. bmp085_data.AC1 = r16(bmp085_i2c_id, 0xAA);
  45. bmp085_data.AC2 = r16(bmp085_i2c_id, 0xAC);
  46. bmp085_data.AC3 = r16(bmp085_i2c_id, 0xAE);
  47. bmp085_data.AC4 = r16u(bmp085_i2c_id, 0xB0);
  48. bmp085_data.AC5 = r16u(bmp085_i2c_id, 0xB2);
  49. bmp085_data.AC6 = r16u(bmp085_i2c_id, 0xB4);
  50. bmp085_data.B1 = r16(bmp085_i2c_id, 0xB6);
  51. bmp085_data.B2 = r16(bmp085_i2c_id, 0xB8);
  52. bmp085_data.MB = r16(bmp085_i2c_id, 0xBA);
  53. bmp085_data.MC = r16(bmp085_i2c_id, 0xBC);
  54. bmp085_data.MD = r16(bmp085_i2c_id, 0xBE);
  55. return 0;
  56. }
  57. static int32_t bmp085_temperature_raw_b5(void) {
  58. int32_t t, X1, X2;
  59. platform_i2c_send_start(bmp085_i2c_id);
  60. platform_i2c_send_address(bmp085_i2c_id, bmp085_i2c_addr, PLATFORM_I2C_DIRECTION_TRANSMITTER);
  61. platform_i2c_send_byte(bmp085_i2c_id, 0xF4);
  62. platform_i2c_send_byte(bmp085_i2c_id, 0x2E);
  63. platform_i2c_send_stop(bmp085_i2c_id);
  64. // Wait for device to complete sampling
  65. os_delay_us(4500);
  66. t = r16u(bmp085_i2c_id, 0xF6);
  67. X1 = ((t - bmp085_data.AC6) * bmp085_data.AC5) >> 15;
  68. X2 = (bmp085_data.MC << 11)/ (X1 + bmp085_data.MD);
  69. return X1 + X2;
  70. }
  71. static int16_t bmp085_temperature(void) {
  72. return (bmp085_temperature_raw_b5() + 8) >> 4;
  73. }
  74. static int bmp085_lua_temperature(lua_State* L) {
  75. lua_pushinteger(L, bmp085_temperature());
  76. return 1;
  77. }
  78. static int32_t bmp085_pressure_raw(int oss) {
  79. int32_t p;
  80. int32_t p1, p2, p3;
  81. platform_i2c_send_start(bmp085_i2c_id);
  82. platform_i2c_send_address(bmp085_i2c_id, bmp085_i2c_addr, PLATFORM_I2C_DIRECTION_TRANSMITTER);
  83. platform_i2c_send_byte(bmp085_i2c_id, 0xF4);
  84. platform_i2c_send_byte(bmp085_i2c_id, 0x34 + 64 * oss);
  85. platform_i2c_send_stop(bmp085_i2c_id);
  86. // Wait for device to complete sampling
  87. switch (oss) {
  88. case 0: os_delay_us( 4500); break;
  89. case 1: os_delay_us( 7500); break;
  90. case 2: os_delay_us(13500); break;
  91. case 3: os_delay_us(25500); break;
  92. }
  93. p1 = r8u(bmp085_i2c_id, 0xF6);
  94. p2 = r8u(bmp085_i2c_id, 0xF7);
  95. p3 = r8u(bmp085_i2c_id, 0xF8);
  96. p = (p1 << 16) | (p2 << 8) | p3;
  97. p = p >> (8 - oss);
  98. return p;
  99. }
  100. static int bmp085_lua_pressure_raw(lua_State* L) {
  101. uint8_t oss = 0;
  102. int32_t p;
  103. if (lua_isnumber(L, 1)) {
  104. oss = luaL_checkinteger(L, 1);
  105. if (oss > 3) {
  106. oss = 3;
  107. }
  108. }
  109. p = bmp085_pressure_raw(oss);
  110. lua_pushinteger(L, p);
  111. return 1;
  112. }
  113. static int bmp085_lua_pressure(lua_State* L) {
  114. uint8_t oss = 0;
  115. int32_t p;
  116. int32_t X1, X2, X3, B3, B5, B6;
  117. uint32_t B4, B7;
  118. if (lua_isnumber(L, 1)) {
  119. oss = luaL_checkinteger(L, 1);
  120. if (oss > 3) {
  121. oss = 3;
  122. }
  123. }
  124. p = bmp085_pressure_raw(oss);
  125. B5 = bmp085_temperature_raw_b5();
  126. B6 = B5 - 4000;
  127. X1 = ((int32_t)bmp085_data.B2 * ((B6 * B6) >> 12)) >> 11;
  128. X2 = ((int32_t)bmp085_data.AC2 * B6) >> 11;
  129. X3 = X1 + X2;
  130. B3 = ((((int32_t)bmp085_data.AC1 << 2) + X3) * (1 << oss) + 2) >> 2;
  131. X1 = ((int32_t)bmp085_data.AC3 * B6) >> 13;
  132. X2 = ((int32_t)bmp085_data.B1 * ((B6 * B6) >> 12)) >> 16;
  133. X3 = (X1 + X2 + 2) >> 2;
  134. B4 = ((uint32_t)bmp085_data.AC4 * (X3 + 32768)) >> 15;
  135. B7 = (p - B3) * (50000 / (1 << oss));
  136. if (B7 < 0x80000000) {
  137. p = (B7 * 2) / B4;
  138. } else {
  139. p = (B7 / B4) * 2;
  140. }
  141. X1 = (p >> 8) * (p >> 8);
  142. X1 = (X1 * 3038) >> 16;
  143. X2 = (-7357 * p) >> 16;
  144. p = p + ((X1 + X2 + 3791) >> 4);
  145. lua_pushinteger(L, p);
  146. return 1;
  147. }
  148. LROT_BEGIN(bmp085, NULL, 0)
  149. LROT_FUNCENTRY( temperature, bmp085_lua_temperature )
  150. LROT_FUNCENTRY( pressure, bmp085_lua_pressure )
  151. LROT_FUNCENTRY( pressure_raw, bmp085_lua_pressure_raw )
  152. LROT_FUNCENTRY( setup, bmp085_setup )
  153. LROT_END(bmp085, NULL, 0)
  154. NODEMCU_MODULE(BMP085, "bmp085", bmp085, NULL);