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