[232] | 1 | #include <L3G.h>
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| 2 | #include <Wire.h>
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| 3 | #include <math.h>
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| 4 |
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| 5 | // Defines ////////////////////////////////////////////////////////////////
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| 6 |
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| 7 | // The Arduino two-wire interface uses a 7-bit number for the address,
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| 8 | // and sets the last bit correctly based on reads and writes
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| 9 | #define D20_SA0_HIGH_ADDRESS 0b1101011 // also applies to D20H
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| 10 | #define D20_SA0_LOW_ADDRESS 0b1101010 // also applies to D20H
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| 11 | #define L3G4200D_SA0_HIGH_ADDRESS 0b1101001
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| 12 | #define L3G4200D_SA0_LOW_ADDRESS 0b1101000
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| 13 |
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| 14 | #define TEST_REG_ERROR -1
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| 15 |
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| 16 | #define D20H_WHO_ID 0xD7
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| 17 | #define D20_WHO_ID 0xD4
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| 18 | #define L3G4200D_WHO_ID 0xD3
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| 19 |
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| 20 | // Constructors ////////////////////////////////////////////////////////////////
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| 21 |
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| 22 | L3G::L3G(void)
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| 23 | {
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| 24 | _device = device_auto;
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| 25 |
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| 26 | io_timeout = 0; // 0 = no timeout
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| 27 | did_timeout = false;
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| 28 | }
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| 29 |
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| 30 | // Public Methods //////////////////////////////////////////////////////////////
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| 31 |
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| 32 | // Did a timeout occur in read() since the last call to timeoutOccurred()?
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| 33 | bool L3G::timeoutOccurred()
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| 34 | {
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| 35 | bool tmp = did_timeout;
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| 36 | did_timeout = false;
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| 37 | return tmp;
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| 38 | }
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| 39 |
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| 40 | void L3G::setTimeout(unsigned int timeout)
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| 41 | {
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| 42 | io_timeout = timeout;
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| 43 | }
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| 44 |
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| 45 | unsigned int L3G::getTimeout()
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| 46 | {
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| 47 | return io_timeout;
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| 48 | }
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| 49 |
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| 50 | bool L3G::init(deviceType device, sa0State sa0)
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| 51 | {
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| 52 | int id;
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| 53 |
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| 54 | // perform auto-detection unless device type and SA0 state were both specified
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| 55 | if (device == device_auto || sa0 == sa0_auto)
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| 56 | {
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| 57 | // check for L3GD20H, D20 if device is unidentified or was specified to be one of these types
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| 58 | if (device == device_auto || device == device_D20H || device == device_D20)
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| 59 | {
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| 60 | // check SA0 high address unless SA0 was specified to be low
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| 61 | if (sa0 != sa0_low && (id = testReg(D20_SA0_HIGH_ADDRESS, WHO_AM_I)) != TEST_REG_ERROR)
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| 62 | {
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| 63 | // device responds to address 1101011; it's a D20H or D20 with SA0 high
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| 64 | sa0 = sa0_high;
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| 65 | if (device == device_auto)
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| 66 | {
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| 67 | // use ID from WHO_AM_I register to determine device type
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| 68 | device = (id == D20H_WHO_ID) ? device_D20H : device_D20;
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| 69 | }
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| 70 | }
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| 71 | // check SA0 low address unless SA0 was specified to be high
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| 72 | else if (sa0 != sa0_high && (id = testReg(D20_SA0_LOW_ADDRESS, WHO_AM_I)) != TEST_REG_ERROR)
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| 73 | {
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| 74 | // device responds to address 1101010; it's a D20H or D20 with SA0 low
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| 75 | sa0 = sa0_low;
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| 76 | if (device == device_auto)
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| 77 | {
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| 78 | // use ID from WHO_AM_I register to determine device type
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| 79 | device = (id == D20H_WHO_ID) ? device_D20H : device_D20;
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| 80 | }
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| 81 | }
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| 82 | }
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| 83 |
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| 84 | // check for L3G4200D if device is still unidentified or was specified to be this type
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| 85 | if (device == device_auto || device == device_4200D)
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| 86 | {
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| 87 | if (sa0 != sa0_low && testReg(L3G4200D_SA0_HIGH_ADDRESS, WHO_AM_I) == L3G4200D_WHO_ID)
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| 88 | {
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| 89 | // device responds to address 1101001; it's a 4200D with SA0 high
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| 90 | device = device_4200D;
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| 91 | sa0 = sa0_high;
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| 92 | }
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| 93 | else if (sa0 != sa0_high && testReg(L3G4200D_SA0_LOW_ADDRESS, WHO_AM_I) == L3G4200D_WHO_ID)
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| 94 | {
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| 95 | // device responds to address 1101000; it's a 4200D with SA0 low
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| 96 | device = device_4200D;
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| 97 | sa0 = sa0_low;
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| 98 | }
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| 99 | }
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| 100 |
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| 101 | // make sure device and SA0 were successfully detected; otherwise, indicate failure
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| 102 | if (device == device_auto || sa0 == sa0_auto)
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| 103 | {
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| 104 | return false;
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| 105 | }
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| 106 | }
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| 107 |
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| 108 | _device = device;
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| 109 |
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| 110 | // set device address
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| 111 | switch (device)
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| 112 | {
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| 113 | case device_D20H:
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| 114 | case device_D20:
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| 115 | address = (sa0 == sa0_high) ? D20_SA0_HIGH_ADDRESS : D20_SA0_LOW_ADDRESS;
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| 116 | break;
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| 117 |
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| 118 | case device_4200D:
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| 119 | address = (sa0 == sa0_high) ? L3G4200D_SA0_HIGH_ADDRESS : L3G4200D_SA0_LOW_ADDRESS;
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| 120 | break;
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| 121 | }
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| 122 |
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| 123 | return true;
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| 124 | }
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| 125 |
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| 126 | /*
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| 127 | Enables the L3G's gyro. Also:
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| 128 | - Sets gyro full scale (gain) to default power-on value of +/- 250 dps
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| 129 | (specified as +/- 245 dps for L3GD20H).
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| 130 | - Selects 200 Hz ODR (output data rate). (Exact rate is specified as 189.4 Hz
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| 131 | for L3GD20H and 190 Hz for L3GD20.)
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| 132 | Note that this function will also reset other settings controlled by
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| 133 | the registers it writes to.
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| 134 | */
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| 135 | void L3G::enableDefault(void)
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| 136 | {
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| 137 | if (_device == device_D20H)
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| 138 | {
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| 139 | // 0x00 = 0b00000000
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| 140 | // Low_ODR = 0 (low speed ODR disabled)
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| 141 | writeReg(LOW_ODR, 0x00);
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| 142 | }
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| 143 |
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| 144 | // 0x00 = 0b00000000
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| 145 | // FS = 00 (+/- 250 dps full scale)
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| 146 | writeReg(CTRL_REG4, 0x00);
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| 147 |
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| 148 | // 0x6F = 0b01101111
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| 149 | // DR = 01 (200 Hz ODR); BW = 10 (50 Hz bandwidth); PD = 1 (normal mode); Zen = Yen = Xen = 1 (all axes enabled)
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| 150 | writeReg(CTRL_REG1, 0x6F);
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| 151 | }
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| 152 |
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| 153 | // Writes a gyro register
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| 154 | void L3G::writeReg(byte reg, byte value)
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| 155 | {
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| 156 | Wire.beginTransmission(address);
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| 157 | Wire.write(reg);
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| 158 | Wire.write(value);
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| 159 | last_status = Wire.endTransmission();
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| 160 | }
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| 161 |
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| 162 | // Reads a gyro register
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| 163 | byte L3G::readReg(byte reg)
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| 164 | {
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| 165 | byte value;
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| 166 |
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| 167 | Wire.beginTransmission(address);
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| 168 | Wire.write(reg);
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| 169 | last_status = Wire.endTransmission();
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| 170 | Wire.requestFrom(address, (byte)1);
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| 171 | value = Wire.read();
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| 172 | Wire.endTransmission();
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| 173 |
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| 174 | return value;
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| 175 | }
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| 176 |
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| 177 | // Reads the 3 gyro channels and stores them in vector g
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| 178 | void L3G::read()
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| 179 | {
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| 180 | Wire.beginTransmission(address);
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| 181 | // assert the MSB of the address to get the gyro
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| 182 | // to do slave-transmit subaddress updating.
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| 183 | Wire.write(OUT_X_L | (1 << 7));
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| 184 | Wire.endTransmission();
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| 185 | Wire.requestFrom(address, (byte)6);
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| 186 |
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| 187 | unsigned int millis_start = millis();
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| 188 | while (Wire.available() < 6)
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| 189 | {
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| 190 | if (io_timeout > 0 && ((unsigned int)millis() - millis_start) > io_timeout)
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| 191 | {
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| 192 | did_timeout = true;
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| 193 | return;
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| 194 | }
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| 195 | }
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| 196 |
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| 197 | uint8_t xlg = Wire.read();
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| 198 | uint8_t xhg = Wire.read();
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| 199 | uint8_t ylg = Wire.read();
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| 200 | uint8_t yhg = Wire.read();
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| 201 | uint8_t zlg = Wire.read();
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| 202 | uint8_t zhg = Wire.read();
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| 203 |
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| 204 | // combine high and low bytes
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| 205 | g.x = (int16_t)(xhg << 8 | xlg);
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| 206 | g.y = (int16_t)(yhg << 8 | ylg);
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| 207 | g.z = (int16_t)(zhg << 8 | zlg);
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| 208 | }
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| 209 |
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| 210 | void L3G::vector_normalize(vector<float> *a)
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| 211 | {
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| 212 | float mag = sqrt(vector_dot(a,a));
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| 213 | a->x /= mag;
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| 214 | a->y /= mag;
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| 215 | a->z /= mag;
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| 216 | }
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| 217 |
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| 218 | // Private Methods //////////////////////////////////////////////////////////////
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| 219 |
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| 220 | int L3G::testReg(byte address, regAddr reg)
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| 221 | {
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| 222 | Wire.beginTransmission(address);
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| 223 | Wire.write((byte)reg);
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| 224 | if (Wire.endTransmission() != 0)
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| 225 | {
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| 226 | return TEST_REG_ERROR;
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| 227 | }
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| 228 |
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| 229 | Wire.requestFrom(address, (byte)1);
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| 230 | if (Wire.available())
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| 231 | {
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| 232 | return Wire.read();
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| 233 | }
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| 234 | else
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| 235 | {
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| 236 | return TEST_REG_ERROR;
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| 237 | }
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| 238 | }
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