1
MMA8452.cpp@17:6e4232c421c0, 2014-03-05 (annotated)
- Committer:
- ashleymills
- Date:
- Wed Mar 05 17:01:00 2014 +0000
- Revision:
- 17:6e4232c421c0
- Parent:
- 16:d6dde2318edc
- Child:
- 19:4d6cd7140a71
Cleaned up debug handling
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
ashleymills | 14:0602b45ca70f | 1 | // Authors: Ashley Mills, Nicholas Herriot |
nherriot | 0:bcf2aa85d7f9 | 2 | /* Copyright (c) 2013 Vodafone, MIT License |
nherriot | 0:bcf2aa85d7f9 | 3 | * |
nherriot | 0:bcf2aa85d7f9 | 4 | * Permission is hereby granted, free of charge, to any person obtaining a copy of this software |
nherriot | 0:bcf2aa85d7f9 | 5 | * and associated documentation files (the "Software"), to deal in the Software without restriction, |
nherriot | 0:bcf2aa85d7f9 | 6 | * including without limitation the rights to use, copy, modify, merge, publish, distribute, |
nherriot | 0:bcf2aa85d7f9 | 7 | * sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is |
nherriot | 0:bcf2aa85d7f9 | 8 | * furnished to do so, subject to the following conditions: |
nherriot | 0:bcf2aa85d7f9 | 9 | * |
nherriot | 0:bcf2aa85d7f9 | 10 | * The above copyright notice and this permission notice shall be included in all copies or |
nherriot | 0:bcf2aa85d7f9 | 11 | * substantial portions of the Software. |
nherriot | 0:bcf2aa85d7f9 | 12 | * |
nherriot | 0:bcf2aa85d7f9 | 13 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING |
nherriot | 0:bcf2aa85d7f9 | 14 | * BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND |
nherriot | 0:bcf2aa85d7f9 | 15 | * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, |
nherriot | 0:bcf2aa85d7f9 | 16 | * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
nherriot | 0:bcf2aa85d7f9 | 17 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. |
nherriot | 0:bcf2aa85d7f9 | 18 | */ |
nherriot | 0:bcf2aa85d7f9 | 19 | |
ashleymills | 11:dfd1e0afcb7b | 20 | #include "MMA8452.h" |
ashleymills | 11:dfd1e0afcb7b | 21 | #include "mbed.h" |
ashleymills | 11:dfd1e0afcb7b | 22 | |
ashleymills | 17:6e4232c421c0 | 23 | #ifdef MMA8452_DEBUG |
ashleymills | 11:dfd1e0afcb7b | 24 | extern Serial pc; |
ashleymills | 17:6e4232c421c0 | 25 | #define MMA8452_DBG(...) pc.printf(__VA_ARGS__); pc.printf("\r\n"); |
ashleymills | 17:6e4232c421c0 | 26 | #else |
ashleymills | 17:6e4232c421c0 | 27 | #define MMA8452_DBG(...) |
ashleymills | 17:6e4232c421c0 | 28 | #endif |
nherriot | 0:bcf2aa85d7f9 | 29 | |
nherriot | 0:bcf2aa85d7f9 | 30 | // Connect module at I2C address using I2C port pins sda and scl |
ashleymills | 11:dfd1e0afcb7b | 31 | MMA8452::MMA8452(PinName sda, PinName scl, int frequency) : _i2c(sda, scl) , _frequency(frequency) { |
ashleymills | 17:6e4232c421c0 | 32 | MMA8452_DBG("Creating MMA8452"); |
ashleymills | 12:172540ff6b8b | 33 | |
ashleymills | 12:172540ff6b8b | 34 | // set I2C frequency |
ashleymills | 11:dfd1e0afcb7b | 35 | _i2c.frequency(_frequency); |
ashleymills | 11:dfd1e0afcb7b | 36 | |
ashleymills | 12:172540ff6b8b | 37 | // setup read and write addresses for convenience |
ashleymills | 11:dfd1e0afcb7b | 38 | _readAddress = MMA8452_ADDRESS | 0x01; |
ashleymills | 11:dfd1e0afcb7b | 39 | _writeAddress = MMA8452_ADDRESS & 0xFE; |
ashleymills | 12:172540ff6b8b | 40 | |
ashleymills | 12:172540ff6b8b | 41 | // set some defaults |
ashleymills | 12:172540ff6b8b | 42 | _bitDepth = BIT_DEPTH_UNKNOWN; |
ashleymills | 12:172540ff6b8b | 43 | setBitDepth(BIT_DEPTH_12); |
ashleymills | 13:4bd8b4cd479d | 44 | _dynamicRange = DYNAMIC_RANGE_UNKNOWN; |
ashleymills | 13:4bd8b4cd479d | 45 | setDynamicRange(DYNAMIC_RANGE_2G); |
ashleymills | 13:4bd8b4cd479d | 46 | |
ashleymills | 17:6e4232c421c0 | 47 | MMA8452_DBG("Done"); |
nherriot | 0:bcf2aa85d7f9 | 48 | } |
nherriot | 0:bcf2aa85d7f9 | 49 | |
nherriot | 0:bcf2aa85d7f9 | 50 | |
nherriot | 0:bcf2aa85d7f9 | 51 | // Destroys instance |
ashleymills | 10:ca9ba7ad4e94 | 52 | MMA8452::~MMA8452() {} |
nherriot | 0:bcf2aa85d7f9 | 53 | |
nherriot | 0:bcf2aa85d7f9 | 54 | // Setting the control register bit 1 to true to activate the MMA8452 |
ashleymills | 10:ca9ba7ad4e94 | 55 | int MMA8452::activate() { |
ashleymills | 6:f6bde04bf8be | 56 | // perform write and return error code |
ashleymills | 12:172540ff6b8b | 57 | return logicalORRegister(MMA8452_CTRL_REG_1,MMA8452_ACTIVE_MASK); |
nherriot | 3:ffb0b1650ca2 | 58 | } |
nherriot | 3:ffb0b1650ca2 | 59 | |
ashleymills | 11:dfd1e0afcb7b | 60 | // Setting the control register bit 1 to 0 to standby the MMA8452 |
ashleymills | 11:dfd1e0afcb7b | 61 | int MMA8452::standby() { |
ashleymills | 11:dfd1e0afcb7b | 62 | // perform write and return error code |
ashleymills | 12:172540ff6b8b | 63 | return logicalANDRegister(MMA8452_CTRL_REG_1,MMA8452_STANDBY_MASK); |
nherriot | 5:b3d0abd97e55 | 64 | } |
nherriot | 5:b3d0abd97e55 | 65 | |
ashleymills | 11:dfd1e0afcb7b | 66 | // this reads a register, applies a bitmask with logical AND, sets a value with logical OR, |
ashleymills | 11:dfd1e0afcb7b | 67 | // and optionally goes into and out of standby at the beginning and end of the function respectively |
ashleymills | 11:dfd1e0afcb7b | 68 | int MMA8452::maskAndApplyRegister(char reg, char mask, char value, int toggleActivation) { |
ashleymills | 11:dfd1e0afcb7b | 69 | if(toggleActivation) { |
ashleymills | 11:dfd1e0afcb7b | 70 | if(standby()) { |
ashleymills | 11:dfd1e0afcb7b | 71 | return 1; |
ashleymills | 11:dfd1e0afcb7b | 72 | } |
ashleymills | 11:dfd1e0afcb7b | 73 | } |
ashleymills | 11:dfd1e0afcb7b | 74 | |
ashleymills | 11:dfd1e0afcb7b | 75 | // read from register |
ashleymills | 11:dfd1e0afcb7b | 76 | char oldValue = 0; |
ashleymills | 11:dfd1e0afcb7b | 77 | if(readRegister(reg,&oldValue)) { |
ashleymills | 11:dfd1e0afcb7b | 78 | return 1; |
ashleymills | 11:dfd1e0afcb7b | 79 | } |
ashleymills | 11:dfd1e0afcb7b | 80 | |
ashleymills | 11:dfd1e0afcb7b | 81 | // apply bitmask |
ashleymills | 11:dfd1e0afcb7b | 82 | oldValue &= mask; |
ashleymills | 11:dfd1e0afcb7b | 83 | |
ashleymills | 11:dfd1e0afcb7b | 84 | // set value |
ashleymills | 11:dfd1e0afcb7b | 85 | oldValue |= value; |
ashleymills | 11:dfd1e0afcb7b | 86 | |
ashleymills | 11:dfd1e0afcb7b | 87 | // write back to register |
ashleymills | 11:dfd1e0afcb7b | 88 | if(writeRegister(reg,oldValue)) { |
ashleymills | 11:dfd1e0afcb7b | 89 | return 1; |
ashleymills | 11:dfd1e0afcb7b | 90 | } |
ashleymills | 11:dfd1e0afcb7b | 91 | |
ashleymills | 11:dfd1e0afcb7b | 92 | if(toggleActivation) { |
ashleymills | 11:dfd1e0afcb7b | 93 | if(activate()) { |
ashleymills | 11:dfd1e0afcb7b | 94 | return 1; |
ashleymills | 11:dfd1e0afcb7b | 95 | } |
ashleymills | 11:dfd1e0afcb7b | 96 | } |
ashleymills | 11:dfd1e0afcb7b | 97 | return 0; |
nherriot | 0:bcf2aa85d7f9 | 98 | } |
nherriot | 0:bcf2aa85d7f9 | 99 | |
ashleymills | 11:dfd1e0afcb7b | 100 | int MMA8452::setDynamicRange(DynamicRange range, int toggleActivation) { |
ashleymills | 13:4bd8b4cd479d | 101 | _dynamicRange = range; |
ashleymills | 11:dfd1e0afcb7b | 102 | return maskAndApplyRegister( |
ashleymills | 11:dfd1e0afcb7b | 103 | MMA8452_XYZ_DATA_CFG, |
ashleymills | 11:dfd1e0afcb7b | 104 | MMA8452_DYNAMIC_RANGE_MASK, |
ashleymills | 11:dfd1e0afcb7b | 105 | range, |
ashleymills | 11:dfd1e0afcb7b | 106 | toggleActivation |
ashleymills | 11:dfd1e0afcb7b | 107 | ); |
nherriot | 0:bcf2aa85d7f9 | 108 | } |
nherriot | 0:bcf2aa85d7f9 | 109 | |
ashleymills | 11:dfd1e0afcb7b | 110 | int MMA8452::setDataRate(DataRateHz dataRate, int toggleActivation) { |
ashleymills | 11:dfd1e0afcb7b | 111 | return maskAndApplyRegister( |
ashleymills | 11:dfd1e0afcb7b | 112 | MMA8452_CTRL_REG_1, |
ashleymills | 11:dfd1e0afcb7b | 113 | MMA8452_DATA_RATE_MASK, |
ashleymills | 11:dfd1e0afcb7b | 114 | dataRate<<MMA8452_DATA_RATE_MASK_SHIFT, |
ashleymills | 11:dfd1e0afcb7b | 115 | toggleActivation |
ashleymills | 11:dfd1e0afcb7b | 116 | ); |
nherriot | 3:ffb0b1650ca2 | 117 | } |
nherriot | 3:ffb0b1650ca2 | 118 | |
ashleymills | 11:dfd1e0afcb7b | 119 | int MMA8452::setBitDepth(BitDepth depth,int toggleActivation) { |
ashleymills | 12:172540ff6b8b | 120 | _bitDepth = depth; |
ashleymills | 11:dfd1e0afcb7b | 121 | return maskAndApplyRegister( |
ashleymills | 11:dfd1e0afcb7b | 122 | MMA8452_CTRL_REG_1, |
ashleymills | 11:dfd1e0afcb7b | 123 | MMA8452_BIT_DEPTH_MASK, |
ashleymills | 11:dfd1e0afcb7b | 124 | depth<<MMA8452_BIT_DEPTH_MASK_SHIFT, |
ashleymills | 11:dfd1e0afcb7b | 125 | toggleActivation |
ashleymills | 11:dfd1e0afcb7b | 126 | ); |
nherriot | 3:ffb0b1650ca2 | 127 | } |
nherriot | 3:ffb0b1650ca2 | 128 | |
ashleymills | 16:d6dde2318edc | 129 | char MMA8452::getMaskedRegister(int reg, char mask) { |
ashleymills | 12:172540ff6b8b | 130 | char rval = 0; |
ashleymills | 16:d6dde2318edc | 131 | if(readRegister(reg,&rval)) { |
ashleymills | 12:172540ff6b8b | 132 | return 0; |
ashleymills | 12:172540ff6b8b | 133 | } |
ashleymills | 16:d6dde2318edc | 134 | return (rval&mask); |
ashleymills | 16:d6dde2318edc | 135 | } |
ashleymills | 16:d6dde2318edc | 136 | |
ashleymills | 16:d6dde2318edc | 137 | int MMA8452::isXYZReady() { |
ashleymills | 16:d6dde2318edc | 138 | return getMaskedRegister(MMA8452_STATUS,MMA8452_STATUS_ZYXDR_MASK)>0; |
ashleymills | 16:d6dde2318edc | 139 | } |
ashleymills | 16:d6dde2318edc | 140 | |
ashleymills | 16:d6dde2318edc | 141 | int MMA8452::isXReady() { |
ashleymills | 16:d6dde2318edc | 142 | return getMaskedRegister(MMA8452_STATUS,MMA8452_STATUS_XDR_MASK)>0; |
nherriot | 1:ef026bf28798 | 143 | } |
ashleymills | 16:d6dde2318edc | 144 | |
ashleymills | 16:d6dde2318edc | 145 | int MMA8452::isYReady() { |
ashleymills | 16:d6dde2318edc | 146 | return getMaskedRegister(MMA8452_STATUS,MMA8452_STATUS_YDR_MASK)>0; |
ashleymills | 16:d6dde2318edc | 147 | } |
ashleymills | 16:d6dde2318edc | 148 | |
ashleymills | 16:d6dde2318edc | 149 | int MMA8452::isZReady() { |
ashleymills | 16:d6dde2318edc | 150 | return getMaskedRegister(MMA8452_STATUS,MMA8452_STATUS_ZDR_MASK)>0; |
ashleymills | 16:d6dde2318edc | 151 | } |
ashleymills | 16:d6dde2318edc | 152 | |
ashleymills | 16:d6dde2318edc | 153 | |
ashleymills | 12:172540ff6b8b | 154 | int MMA8452::getDeviceID(char *dst) { |
ashleymills | 12:172540ff6b8b | 155 | return readRegister(MMA8452_WHO_AM_I,dst); |
nherriot | 3:ffb0b1650ca2 | 156 | } |
nherriot | 3:ffb0b1650ca2 | 157 | |
ashleymills | 12:172540ff6b8b | 158 | int MMA8452::getStatus(char* dst) { |
ashleymills | 12:172540ff6b8b | 159 | return readRegister(MMA8452_STATUS,dst); |
nherriot | 3:ffb0b1650ca2 | 160 | } |
nherriot | 0:bcf2aa85d7f9 | 161 | |
ashleymills | 11:dfd1e0afcb7b | 162 | MMA8452::DynamicRange MMA8452::getDynamicRange() { |
ashleymills | 11:dfd1e0afcb7b | 163 | char rval = 0; |
ashleymills | 12:172540ff6b8b | 164 | if(readRegister(MMA8452_XYZ_DATA_CFG,&rval)) { |
ashleymills | 11:dfd1e0afcb7b | 165 | return MMA8452::DYNAMIC_RANGE_UNKNOWN; |
ashleymills | 11:dfd1e0afcb7b | 166 | } |
ashleymills | 11:dfd1e0afcb7b | 167 | rval &= (MMA8452_DYNAMIC_RANGE_MASK^0xFF); |
ashleymills | 11:dfd1e0afcb7b | 168 | return (MMA8452::DynamicRange)rval; |
ashleymills | 11:dfd1e0afcb7b | 169 | } |
ashleymills | 11:dfd1e0afcb7b | 170 | |
ashleymills | 11:dfd1e0afcb7b | 171 | MMA8452::DataRateHz MMA8452::getDataRate() { |
ashleymills | 11:dfd1e0afcb7b | 172 | char rval = 0; |
ashleymills | 11:dfd1e0afcb7b | 173 | if(readRegister(MMA8452_CTRL_REG_1,&rval)) { |
ashleymills | 11:dfd1e0afcb7b | 174 | return MMA8452::RATE_UNKNOWN; |
ashleymills | 11:dfd1e0afcb7b | 175 | } |
ashleymills | 11:dfd1e0afcb7b | 176 | // logical AND with inverse of mask |
ashleymills | 11:dfd1e0afcb7b | 177 | rval = rval&(MMA8452_DATA_RATE_MASK^0xFF); |
ashleymills | 11:dfd1e0afcb7b | 178 | // shift back into position |
ashleymills | 11:dfd1e0afcb7b | 179 | rval >>= MMA8452_DATA_RATE_MASK_SHIFT; |
ashleymills | 11:dfd1e0afcb7b | 180 | return (MMA8452::DataRateHz)rval; |
ashleymills | 11:dfd1e0afcb7b | 181 | } |
ashleymills | 11:dfd1e0afcb7b | 182 | |
nherriot | 0:bcf2aa85d7f9 | 183 | // Reads xyz |
ashleymills | 13:4bd8b4cd479d | 184 | int MMA8452::readXYZRaw(char *dst) { |
ashleymills | 12:172540ff6b8b | 185 | if(_bitDepth==BIT_DEPTH_UNKNOWN) { |
ashleymills | 12:172540ff6b8b | 186 | return 1; |
ashleymills | 12:172540ff6b8b | 187 | } |
ashleymills | 12:172540ff6b8b | 188 | int readLen = 3; |
ashleymills | 12:172540ff6b8b | 189 | if(_bitDepth==BIT_DEPTH_12) { |
ashleymills | 12:172540ff6b8b | 190 | readLen = 6; |
ashleymills | 12:172540ff6b8b | 191 | } |
ashleymills | 12:172540ff6b8b | 192 | return readRegister(MMA8452_OUT_X_MSB,dst,readLen); |
nherriot | 1:ef026bf28798 | 193 | } |
nherriot | 0:bcf2aa85d7f9 | 194 | |
ashleymills | 13:4bd8b4cd479d | 195 | int MMA8452::readXYZCounts(int *x, int *y, int *z) { |
ashleymills | 13:4bd8b4cd479d | 196 | char buf[6]; |
ashleymills | 13:4bd8b4cd479d | 197 | if(readXYZRaw((char*)&buf)) { |
ashleymills | 13:4bd8b4cd479d | 198 | return 1; |
ashleymills | 13:4bd8b4cd479d | 199 | } |
ashleymills | 13:4bd8b4cd479d | 200 | if(_bitDepth==BIT_DEPTH_12) { |
ashleymills | 13:4bd8b4cd479d | 201 | *x = twelveBitToSigned(&buf[0]); |
ashleymills | 13:4bd8b4cd479d | 202 | *y = twelveBitToSigned(&buf[2]); |
ashleymills | 13:4bd8b4cd479d | 203 | *z = twelveBitToSigned(&buf[4]); |
ashleymills | 13:4bd8b4cd479d | 204 | } else { |
ashleymills | 13:4bd8b4cd479d | 205 | *x = eightBitToSigned(&buf[0]); |
ashleymills | 13:4bd8b4cd479d | 206 | *y = eightBitToSigned(&buf[1]); |
ashleymills | 13:4bd8b4cd479d | 207 | *z = eightBitToSigned(&buf[2]); |
ashleymills | 13:4bd8b4cd479d | 208 | } |
ashleymills | 13:4bd8b4cd479d | 209 | |
ashleymills | 13:4bd8b4cd479d | 210 | return 0; |
ashleymills | 13:4bd8b4cd479d | 211 | } |
ashleymills | 13:4bd8b4cd479d | 212 | |
ashleymills | 13:4bd8b4cd479d | 213 | double MMA8452::convertCountToGravity(int count, int countsPerG) { |
ashleymills | 13:4bd8b4cd479d | 214 | return (double)count/(double)countsPerG; |
ashleymills | 13:4bd8b4cd479d | 215 | } |
ashleymills | 13:4bd8b4cd479d | 216 | |
ashleymills | 13:4bd8b4cd479d | 217 | int MMA8452::readXYZGravity(double *x, double *y, double *z) { |
ashleymills | 13:4bd8b4cd479d | 218 | int xCount = 0, yCount = 0, zCount = 0; |
ashleymills | 13:4bd8b4cd479d | 219 | if(readXYZCounts(&xCount,&yCount,&zCount)) { |
ashleymills | 13:4bd8b4cd479d | 220 | return 1; |
ashleymills | 13:4bd8b4cd479d | 221 | } |
ashleymills | 13:4bd8b4cd479d | 222 | |
ashleymills | 13:4bd8b4cd479d | 223 | // assume starting with DYNAMIC_RANGE_2G and BIT_DEPTH_12 |
ashleymills | 13:4bd8b4cd479d | 224 | int countsPerG = 1024; |
ashleymills | 13:4bd8b4cd479d | 225 | if(_bitDepth==BIT_DEPTH_8) { |
ashleymills | 13:4bd8b4cd479d | 226 | countsPerG = 64; |
ashleymills | 13:4bd8b4cd479d | 227 | } |
ashleymills | 13:4bd8b4cd479d | 228 | switch(_dynamicRange) { |
ashleymills | 13:4bd8b4cd479d | 229 | case DYNAMIC_RANGE_4G: |
ashleymills | 13:4bd8b4cd479d | 230 | countsPerG /= 2; |
ashleymills | 13:4bd8b4cd479d | 231 | break; |
ashleymills | 13:4bd8b4cd479d | 232 | case DYNAMIC_RANGE_8G: |
ashleymills | 13:4bd8b4cd479d | 233 | countsPerG /= 4; |
ashleymills | 13:4bd8b4cd479d | 234 | break; |
ashleymills | 13:4bd8b4cd479d | 235 | } |
ashleymills | 13:4bd8b4cd479d | 236 | |
ashleymills | 13:4bd8b4cd479d | 237 | *x = convertCountToGravity(xCount,countsPerG); |
ashleymills | 13:4bd8b4cd479d | 238 | *y = convertCountToGravity(yCount,countsPerG); |
ashleymills | 13:4bd8b4cd479d | 239 | *z = convertCountToGravity(zCount,countsPerG); |
ashleymills | 13:4bd8b4cd479d | 240 | return 0; |
ashleymills | 13:4bd8b4cd479d | 241 | } |
ashleymills | 13:4bd8b4cd479d | 242 | |
ashleymills | 11:dfd1e0afcb7b | 243 | // apply an AND mask to a register. read register value, apply mask, write it back |
ashleymills | 11:dfd1e0afcb7b | 244 | int MMA8452::logicalANDRegister(char addr, char mask) { |
ashleymills | 11:dfd1e0afcb7b | 245 | char value = 0; |
ashleymills | 11:dfd1e0afcb7b | 246 | // read register value |
ashleymills | 11:dfd1e0afcb7b | 247 | if(readRegister(addr,&value)) { |
ashleymills | 11:dfd1e0afcb7b | 248 | return 0; |
ashleymills | 11:dfd1e0afcb7b | 249 | } |
ashleymills | 11:dfd1e0afcb7b | 250 | // apply mask |
ashleymills | 11:dfd1e0afcb7b | 251 | value &= mask; |
ashleymills | 11:dfd1e0afcb7b | 252 | return writeRegister(addr,value); |
ashleymills | 11:dfd1e0afcb7b | 253 | } |
ashleymills | 11:dfd1e0afcb7b | 254 | |
ashleymills | 11:dfd1e0afcb7b | 255 | |
ashleymills | 11:dfd1e0afcb7b | 256 | // apply an OR mask to a register. read register value, apply mask, write it back |
ashleymills | 11:dfd1e0afcb7b | 257 | int MMA8452::logicalORRegister(char addr, char mask) { |
ashleymills | 11:dfd1e0afcb7b | 258 | char value = 0; |
ashleymills | 11:dfd1e0afcb7b | 259 | // read register value |
ashleymills | 11:dfd1e0afcb7b | 260 | if(readRegister(addr,&value)) { |
ashleymills | 11:dfd1e0afcb7b | 261 | return 0; |
ashleymills | 11:dfd1e0afcb7b | 262 | } |
ashleymills | 11:dfd1e0afcb7b | 263 | // apply mask |
ashleymills | 11:dfd1e0afcb7b | 264 | value |= mask; |
ashleymills | 11:dfd1e0afcb7b | 265 | return writeRegister(addr,value); |
ashleymills | 11:dfd1e0afcb7b | 266 | } |
ashleymills | 11:dfd1e0afcb7b | 267 | |
ashleymills | 11:dfd1e0afcb7b | 268 | // apply an OR mask to a register. read register value, apply mask, write it back |
ashleymills | 11:dfd1e0afcb7b | 269 | int MMA8452::logicalXORRegister(char addr, char mask) { |
ashleymills | 11:dfd1e0afcb7b | 270 | char value = 0; |
ashleymills | 11:dfd1e0afcb7b | 271 | // read register value |
ashleymills | 11:dfd1e0afcb7b | 272 | if(readRegister(addr,&value)) { |
ashleymills | 11:dfd1e0afcb7b | 273 | return 0; |
ashleymills | 11:dfd1e0afcb7b | 274 | } |
ashleymills | 11:dfd1e0afcb7b | 275 | // apply mask |
ashleymills | 11:dfd1e0afcb7b | 276 | value ^= mask; |
ashleymills | 11:dfd1e0afcb7b | 277 | return writeRegister(addr,value); |
ashleymills | 11:dfd1e0afcb7b | 278 | } |
ashleymills | 11:dfd1e0afcb7b | 279 | |
ashleymills | 11:dfd1e0afcb7b | 280 | // Write register (The device must be placed in Standby Mode to change the value of the registers) |
ashleymills | 11:dfd1e0afcb7b | 281 | int MMA8452::writeRegister(char addr, char data) { |
ashleymills | 11:dfd1e0afcb7b | 282 | // what this actually does is the following |
ashleymills | 11:dfd1e0afcb7b | 283 | // 1. tell I2C bus to start transaction |
ashleymills | 11:dfd1e0afcb7b | 284 | // 2. tell slave we want to write (slave address & write flag) |
ashleymills | 11:dfd1e0afcb7b | 285 | // 3. send the write address |
ashleymills | 11:dfd1e0afcb7b | 286 | // 4. send the data to write |
ashleymills | 11:dfd1e0afcb7b | 287 | // 5. tell I2C bus to end transaction |
ashleymills | 11:dfd1e0afcb7b | 288 | |
ashleymills | 11:dfd1e0afcb7b | 289 | // we can wrap this up in the I2C library write function |
ashleymills | 11:dfd1e0afcb7b | 290 | char buf[2] = {0,0}; |
ashleymills | 11:dfd1e0afcb7b | 291 | buf[0] = addr; |
ashleymills | 11:dfd1e0afcb7b | 292 | buf[1] = data; |
ashleymills | 11:dfd1e0afcb7b | 293 | return _i2c.write(MMA8452_ADDRESS, buf,2); |
ashleymills | 11:dfd1e0afcb7b | 294 | // note, could also do return writeRegister(addr,&data,1); |
nherriot | 0:bcf2aa85d7f9 | 295 | } |
nherriot | 0:bcf2aa85d7f9 | 296 | |
ashleymills | 13:4bd8b4cd479d | 297 | int MMA8452::eightBitToSigned(char *buf) { |
ashleymills | 13:4bd8b4cd479d | 298 | return (int8_t)*buf; |
ashleymills | 13:4bd8b4cd479d | 299 | } |
ashleymills | 13:4bd8b4cd479d | 300 | |
ashleymills | 13:4bd8b4cd479d | 301 | int MMA8452::twelveBitToSigned(char *buf) { |
ashleymills | 13:4bd8b4cd479d | 302 | // cheat by using the int16_t internal type |
ashleymills | 13:4bd8b4cd479d | 303 | // all we need to do is convert to little-endian format and shift right |
ashleymills | 13:4bd8b4cd479d | 304 | int16_t x = 0; |
ashleymills | 13:4bd8b4cd479d | 305 | ((char*)&x)[1] = buf[0]; |
ashleymills | 13:4bd8b4cd479d | 306 | ((char*)&x)[0] = buf[1]; |
ashleymills | 13:4bd8b4cd479d | 307 | // note this only works because the below is an arithmetic right shift |
ashleymills | 13:4bd8b4cd479d | 308 | return x>>4; |
ashleymills | 13:4bd8b4cd479d | 309 | } |
ashleymills | 11:dfd1e0afcb7b | 310 | |
ashleymills | 11:dfd1e0afcb7b | 311 | int MMA8452::writeRegister(char addr, char *data, int nbytes) { |
ashleymills | 11:dfd1e0afcb7b | 312 | // writing multiple bytes is a little bit annoying because |
ashleymills | 11:dfd1e0afcb7b | 313 | // the I2C library doesn't support sending the address separately |
ashleymills | 11:dfd1e0afcb7b | 314 | // so we just do it manually |
nherriot | 0:bcf2aa85d7f9 | 315 | |
ashleymills | 11:dfd1e0afcb7b | 316 | // 1. tell I2C bus to start transaction |
ashleymills | 11:dfd1e0afcb7b | 317 | _i2c.start(); |
ashleymills | 11:dfd1e0afcb7b | 318 | // 2. tell slave we want to write (slave address & write flag) |
ashleymills | 11:dfd1e0afcb7b | 319 | if(_i2c.write(_writeAddress)!=1) { |
ashleymills | 11:dfd1e0afcb7b | 320 | return 1; |
ashleymills | 11:dfd1e0afcb7b | 321 | } |
ashleymills | 11:dfd1e0afcb7b | 322 | // 3. send the write address |
ashleymills | 11:dfd1e0afcb7b | 323 | if(_i2c.write(addr)!=1) { |
ashleymills | 11:dfd1e0afcb7b | 324 | return 1; |
ashleymills | 11:dfd1e0afcb7b | 325 | } |
ashleymills | 11:dfd1e0afcb7b | 326 | // 4. send the data to write |
ashleymills | 11:dfd1e0afcb7b | 327 | for(int i=0; i<nbytes; i++) { |
ashleymills | 11:dfd1e0afcb7b | 328 | if(_i2c.write(data[i])!=1) { |
ashleymills | 11:dfd1e0afcb7b | 329 | return 1; |
ashleymills | 11:dfd1e0afcb7b | 330 | } |
ashleymills | 11:dfd1e0afcb7b | 331 | } |
ashleymills | 11:dfd1e0afcb7b | 332 | // 5. tell I2C bus to end transaction |
ashleymills | 11:dfd1e0afcb7b | 333 | _i2c.stop(); |
ashleymills | 11:dfd1e0afcb7b | 334 | return 0; |
ashleymills | 11:dfd1e0afcb7b | 335 | } |
ashleymills | 11:dfd1e0afcb7b | 336 | |
ashleymills | 11:dfd1e0afcb7b | 337 | int MMA8452::readRegister(char addr, char *dst, int nbytes) { |
ashleymills | 11:dfd1e0afcb7b | 338 | // this is a bit odd, but basically proceeds like this |
ashleymills | 11:dfd1e0afcb7b | 339 | // 1. Send a start command |
ashleymills | 11:dfd1e0afcb7b | 340 | // 2. Tell the slave we want to write (slave address & write flag) |
ashleymills | 11:dfd1e0afcb7b | 341 | // 3. Send the address of the register (addr) |
ashleymills | 11:dfd1e0afcb7b | 342 | // 4. Send another start command to delineate read portion |
ashleymills | 11:dfd1e0afcb7b | 343 | // 5. Tell the slave we want to read (slave address & read flag) |
ashleymills | 11:dfd1e0afcb7b | 344 | // 6. Read the register value bytes |
ashleymills | 11:dfd1e0afcb7b | 345 | // 7. Send a stop command |
ashleymills | 11:dfd1e0afcb7b | 346 | |
ashleymills | 11:dfd1e0afcb7b | 347 | // we can wrap this process in the I2C library read and write commands |
ashleymills | 11:dfd1e0afcb7b | 348 | if(_i2c.write(MMA8452_ADDRESS,&addr,1,true)) { |
ashleymills | 11:dfd1e0afcb7b | 349 | return 1; |
ashleymills | 8:89272163f395 | 350 | } |
ashleymills | 11:dfd1e0afcb7b | 351 | return _i2c.read(MMA8452_ADDRESS,dst,nbytes); |
ashleymills | 11:dfd1e0afcb7b | 352 | } |
ashleymills | 11:dfd1e0afcb7b | 353 | |
ashleymills | 11:dfd1e0afcb7b | 354 | // most registers are 1 byte, so here is a convenience function |
ashleymills | 11:dfd1e0afcb7b | 355 | int MMA8452::readRegister(char addr, char *dst) { |
ashleymills | 11:dfd1e0afcb7b | 356 | return readRegister(addr,dst,1); |
nherriot | 0:bcf2aa85d7f9 | 357 | } |
ashleymills | 11:dfd1e0afcb7b | 358 | |
ashleymills | 17:6e4232c421c0 | 359 | #ifdef MMA8452_DEBUG |
ashleymills | 11:dfd1e0afcb7b | 360 | void MMA8452::debugRegister(char reg) { |
ashleymills | 11:dfd1e0afcb7b | 361 | // get register value |
ashleymills | 11:dfd1e0afcb7b | 362 | char v = 0; |
ashleymills | 11:dfd1e0afcb7b | 363 | if(readRegister(reg,&v)) { |
ashleymills | 17:6e4232c421c0 | 364 | MMA8452_DBG("Error reading specified register"); |
ashleymills | 11:dfd1e0afcb7b | 365 | return; |
ashleymills | 11:dfd1e0afcb7b | 366 | } |
ashleymills | 11:dfd1e0afcb7b | 367 | // print out details |
ashleymills | 11:dfd1e0afcb7b | 368 | switch(reg) { |
ashleymills | 11:dfd1e0afcb7b | 369 | case MMA8452_CTRL_REG_1: |
ashleymills | 17:6e4232c421c0 | 370 | MMA8452_DBG("CTRL_REG_1 has value: 0x%x",v); |
ashleymills | 17:6e4232c421c0 | 371 | MMA8452_DBG(" 7 ALSP_RATE_1: %d",(v&0x80)>>7); |
ashleymills | 17:6e4232c421c0 | 372 | MMA8452_DBG(" 6 ALSP_RATE_0: %d",(v&0x40)>>6); |
ashleymills | 17:6e4232c421c0 | 373 | MMA8452_DBG(" 5 DR2: %d", (v&0x20)>>5); |
ashleymills | 17:6e4232c421c0 | 374 | MMA8452_DBG(" 4 DR1: %d", (v&0x10)>>4); |
ashleymills | 17:6e4232c421c0 | 375 | MMA8452_DBG(" 3 DR0: %d", (v&0x08)>>3); |
ashleymills | 17:6e4232c421c0 | 376 | MMA8452_DBG(" 2 LNOISE: %d", (v&0x04)>>2); |
ashleymills | 17:6e4232c421c0 | 377 | MMA8452_DBG(" 1 FREAD: %d", (v&0x02)>>1); |
ashleymills | 17:6e4232c421c0 | 378 | MMA8452_DBG(" 0 ACTIVE: %d", (v&0x01)); |
ashleymills | 11:dfd1e0afcb7b | 379 | break; |
ashleymills | 11:dfd1e0afcb7b | 380 | |
ashleymills | 11:dfd1e0afcb7b | 381 | case MMA8452_XYZ_DATA_CFG: |
ashleymills | 17:6e4232c421c0 | 382 | MMA8452_DBG("XYZ_DATA_CFG has value: 0x%x",v); |
ashleymills | 17:6e4232c421c0 | 383 | MMA8452_DBG(" 7 Unused: %d", (v&0x80)>>7); |
ashleymills | 17:6e4232c421c0 | 384 | MMA8452_DBG(" 6 0: %d", (v&0x40)>>6); |
ashleymills | 17:6e4232c421c0 | 385 | MMA8452_DBG(" 5 0: %d", (v&0x20)>>5); |
ashleymills | 17:6e4232c421c0 | 386 | MMA8452_DBG(" 4 HPF_Out: %d",(v&0x10)>>4); |
ashleymills | 17:6e4232c421c0 | 387 | MMA8452_DBG(" 3 0: %d", (v&0x08)>>3); |
ashleymills | 17:6e4232c421c0 | 388 | MMA8452_DBG(" 2 0: %d", (v&0x04)>>2); |
ashleymills | 17:6e4232c421c0 | 389 | MMA8452_DBG(" 1 FS1: %d", (v&0x02)>>1); |
ashleymills | 17:6e4232c421c0 | 390 | MMA8452_DBG(" 0 FS0: %d", (v&0x01)); |
ashleymills | 11:dfd1e0afcb7b | 391 | switch(v&0x03) { |
ashleymills | 11:dfd1e0afcb7b | 392 | case 0: |
ashleymills | 17:6e4232c421c0 | 393 | MMA8452_DBG("Dynamic range: 2G"); |
ashleymills | 11:dfd1e0afcb7b | 394 | break; |
ashleymills | 11:dfd1e0afcb7b | 395 | case 1: |
ashleymills | 17:6e4232c421c0 | 396 | MMA8452_DBG("Dynamic range: 4G"); |
ashleymills | 11:dfd1e0afcb7b | 397 | break; |
ashleymills | 11:dfd1e0afcb7b | 398 | case 2: |
ashleymills | 17:6e4232c421c0 | 399 | MMA8452_DBG("Dynamic range: 8G"); |
ashleymills | 11:dfd1e0afcb7b | 400 | break; |
ashleymills | 11:dfd1e0afcb7b | 401 | default: |
ashleymills | 17:6e4232c421c0 | 402 | MMA8452_DBG("Unknown dynamic range"); |
ashleymills | 11:dfd1e0afcb7b | 403 | break; |
ashleymills | 11:dfd1e0afcb7b | 404 | } |
ashleymills | 11:dfd1e0afcb7b | 405 | break; |
ashleymills | 11:dfd1e0afcb7b | 406 | |
ashleymills | 12:172540ff6b8b | 407 | case MMA8452_STATUS: |
ashleymills | 17:6e4232c421c0 | 408 | MMA8452_DBG("STATUS has value: 0x%x",v); |
ashleymills | 17:6e4232c421c0 | 409 | MMA8452_DBG(" 7 ZYXOW: %d",(v&0x80)>>7); |
ashleymills | 17:6e4232c421c0 | 410 | MMA8452_DBG(" 6 ZOW: %d", (v&0x40)>>6); |
ashleymills | 17:6e4232c421c0 | 411 | MMA8452_DBG(" 5 YOW: %d", (v&0x20)>>5); |
ashleymills | 17:6e4232c421c0 | 412 | MMA8452_DBG(" 4 XOW: %d", (v&0x10)>>4); |
ashleymills | 17:6e4232c421c0 | 413 | MMA8452_DBG(" 3 ZYXDR: %d",(v&0x08)>>3); |
ashleymills | 17:6e4232c421c0 | 414 | MMA8452_DBG(" 2 ZDR: %d", (v&0x04)>>2); |
ashleymills | 17:6e4232c421c0 | 415 | MMA8452_DBG(" 1 YDR: %d", (v&0x02)>>1); |
ashleymills | 17:6e4232c421c0 | 416 | MMA8452_DBG(" 0 XDR: %d", (v&0x01)); |
ashleymills | 12:172540ff6b8b | 417 | break; |
ashleymills | 12:172540ff6b8b | 418 | |
ashleymills | 11:dfd1e0afcb7b | 419 | default: |
ashleymills | 17:6e4232c421c0 | 420 | MMA8452_DBG("Unknown register address: 0x%x",reg); |
ashleymills | 11:dfd1e0afcb7b | 421 | break; |
ashleymills | 11:dfd1e0afcb7b | 422 | } |
ashleymills | 17:6e4232c421c0 | 423 | } |
ashleymills | 17:6e4232c421c0 | 424 | #endif |