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- /*
- * Driver for Honeywell HMC5883L compass IC
- *
- * Code based on BMP085 driver.
- */
- #include "module.h"
- #include "lauxlib.h"
- #include "platform.h"
- #include <stdlib.h>
- #include <string.h>
- static const uint32_t hmc5883_i2c_id = 0;
- static const uint8_t hmc5883_i2c_addr = 0x1E;
- static uint8_t r8u(uint32_t id, uint8_t reg) {
- uint8_t ret;
- platform_i2c_send_start(id);
- platform_i2c_send_address(id, hmc5883_i2c_addr, PLATFORM_I2C_DIRECTION_TRANSMITTER);
- platform_i2c_send_byte(id, reg);
- platform_i2c_send_stop(id);
- platform_i2c_send_start(id);
- platform_i2c_send_address(id, hmc5883_i2c_addr, PLATFORM_I2C_DIRECTION_RECEIVER);
- ret = platform_i2c_recv_byte(id, 0);
- platform_i2c_send_stop(id);
- return ret;
- }
- static void w8u(uint32_t id, uint8_t reg, uint8_t val) {
- platform_i2c_send_start(hmc5883_i2c_id);
- platform_i2c_send_address(hmc5883_i2c_id, hmc5883_i2c_addr, PLATFORM_I2C_DIRECTION_TRANSMITTER);
- platform_i2c_send_byte(hmc5883_i2c_id, reg);
- platform_i2c_send_byte(hmc5883_i2c_id, val);
- platform_i2c_send_stop(hmc5883_i2c_id);
- }
- static int hmc5883_setup(lua_State* L) {
- uint8_t devid_a, devid_b, devid_c;
- devid_a = r8u(hmc5883_i2c_id, 10);
- devid_b = r8u(hmc5883_i2c_id, 11);
- devid_c = r8u(hmc5883_i2c_id, 12);
- if ((devid_a != 0x48) || (devid_b != 0x34) || (devid_c != 0x33)) {
- return luaL_error(L, "device not found");
- }
- // 8 sample average, 15 Hz update rate, normal measurement
- w8u(hmc5883_i2c_id, 0x00, 0x70);
- // Gain = 5
- w8u(hmc5883_i2c_id, 0x01, 0xA0);
- // Continuous measurement
- w8u(hmc5883_i2c_id, 0x02, 0x00);
- return 0;
- }
- static int hmc5883_read(lua_State* L) {
- uint8_t data[6];
- int x,y,z;
- int i;
- platform_i2c_send_start(hmc5883_i2c_id);
- platform_i2c_send_address(hmc5883_i2c_id, hmc5883_i2c_addr, PLATFORM_I2C_DIRECTION_TRANSMITTER);
- platform_i2c_send_byte(hmc5883_i2c_id, 0x03);
- platform_i2c_send_stop(hmc5883_i2c_id);
- platform_i2c_send_start(hmc5883_i2c_id);
- platform_i2c_send_address(hmc5883_i2c_id, hmc5883_i2c_addr, PLATFORM_I2C_DIRECTION_RECEIVER);
- for (i=0; i<5; i++) {
- data[i] = platform_i2c_recv_byte(hmc5883_i2c_id, 1);
- }
- data[5] = platform_i2c_recv_byte(hmc5883_i2c_id, 0);
- platform_i2c_send_stop(hmc5883_i2c_id);
- x = (int16_t) ((data[0] << 8) | data[1]);
- z = (int16_t) ((data[2] << 8) | data[3]);
- y = (int16_t) ((data[4] << 8) | data[5]);
- lua_pushinteger(L, x);
- lua_pushinteger(L, y);
- lua_pushinteger(L, z);
- return 3;
- }
- LROT_BEGIN(hmc5883)
- LROT_FUNCENTRY( read, hmc5883_read )
- LROT_FUNCENTRY( setup, hmc5883_setup )
- LROT_END( hmc5883, NULL, 0 )
- NODEMCU_MODULE(HMC5883L, "hmc5883l", hmc5883, NULL);
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