Interface library for the Devantech SRF02/SRF08 ultrasonic i2c rangers. Depends on I2cRtosDriver lib!
Diff: Srf0208IF.h
- Revision:
- 3:70c946ba29cc
- Parent:
- 2:dfc8b09b4e3b
--- a/Srf0208IF.h Sun May 26 20:52:27 2013 +0000 +++ b/Srf0208IF.h Sat Jun 01 07:40:00 2013 +0000 @@ -18,26 +18,26 @@ /// little helper that translates two raw bytes into a word static int twoByte2int(const char* data){ - return ((static_cast<uint16_t>(*(data)))<<8) | static_cast<uint16_t>(*(data+1)); + return ((static_cast<int>(*(data)))<<8) | static_cast<int>(*(data+1)); } /// little helper that translates the us transit time into a distance in mm static int time2dist_us2mm(int us){ - return us!=-1 ? (us*sonicSpeed)>>1 : us; + return us!=-1 ? (us*sonicSpeed)>>11 : -1; } - /// sonic speed in m/s @ 21°C ... c=(331.5+0.6*T/°C)m/s - /// To calculate the distance in mm: Multiply the µs measurement with this constant and divide by 2 + /// sonic speed in m/s @ 21C ... c=(331.5+0.6*T/C)m/s + /// To calculate the distance in mm: Multiply the us measurement with this constant and divide by 2 static const int sonicSpeed = 344; /// The constructor Srf0208IF(int adr, I2CMasterRtos& i2c): m_adr(adr), m_i2c(i2c){}; - /// Trigger ranging. Result can be read back after 66ms via triggerEchoMeasurement() + /// Trigger ranging. Result can be read back after 66ms via triggerEchoMeasurement(). /// @return true on success bool triggerRanging(); - /// Read back measured transit time in µs of the last triggerRanging() or triggerEchoMeasurement() request. + /// Read back measured transit time in us of the last triggerRanging() or triggerEchoMeasurement() request. /// Depending on the distance the Measurement takes up to 66ms. /// @return -1 on error int readTransitTime_us(); @@ -49,21 +49,21 @@ return time2dist_us2mm(readTransitTime_us()); }; - /// Assign a new adress to the SRF ranger device. Available 8bit addresses: E0, E2, E4 ... FE + /// Assign a new adress to the SRF ranger device. Available 8bit addresses: E0, E2, E4 ... FE. /// Ensure that only one SRF device is connected to the bus void resetI2CAdress(int newAddress); - /// Reads the SRF's SW revision + /// Reads the SRF's SW revision. /// @return -1 on error int readSWRevision(); - /// Returns true if ranging is done + /// Returns true if ranging is done. bool rangingCompleted(){ return readSWRevision()!=-1; } }; -/// Provides special features of the SRF02 +/// Provides an interface to special features of the SRF02 class Srf02IF : public Srf0208IF { public: @@ -71,19 +71,19 @@ /// The constructor Srf02IF(int adr, I2CMasterRtos& i2c):Srf0208IF(adr,i2c){}; - /// Just send a ping + /// Just send a ping. /// @return true on success bool triggerPing(); - /// Just wait for an echo and measure the time - /// Result can be read back after 66ms via triggerEchoMeasurement() + /// Just wait for an echo and measure the time. + /// Result can be read back after 66ms via triggerEchoMeasurement(). /// @return true on success bool triggerEchoMeasurement(); - /// Read current minimum range from srf02 + /// Read current minimum range from srf02. int readMinimalTransitTime_us(); - /// Read current minimum range from srf02 + /// Read current minimum range from srf02. int readMinimalDistance_mm(){ return time2dist_us2mm(readMinimalTransitTime_us()); } @@ -100,7 +100,7 @@ /// The constructor Srf08IF(int adr, I2CMasterRtos& i2c):Srf0208IF(adr,i2c){}; - /// read light sensor measurement + /// read light sensor measurement. /// @return -1 on error int readBrightness(); @@ -109,19 +109,19 @@ bool triggerANNRanging(); /// Set maximum distance. Use to reduce measurement time. - /// @param maxDst maximum distance 0..0xff (1+maxDst)*43mm => 43mm..11m / 3ms..64ms + /// @param maxDst maximum distance 0..0xff (1+maxDst)*43mm => 43mm..11m / 3ms..64ms. /// @return true on success bool writeMaxDist(int maxDst); /// Set/Limit maximum gain. Use to suppress roving echos from previous measurements. /// Necessary at mesurement rates higher than 1/66ms=15Hz. - /// During measurement the analog signal amplification is increased every 70µs until + /// During measurement the analog signal amplification is increased every 70us until /// the maximum gain is reached after 31 steps at ~390mm. /// @param maxGain 0..31 / 0x0..0x1f =>magic non linear function=> 94..1025 (see SRF08 docu) /// @return true on success bool writeMaxGain(int maxGain); - /// Get transit time (µs) of n'th echo from internal buffer. + /// Get transit time (us) of n'th echo from internal buffer. /// Call burstRead() before! /// @param echoIdx 0..16 int getTransitTimeFromRawBuffer_us(int echoIdx) const { @@ -142,12 +142,12 @@ } /// Get ANN data from internal buffer /// Call burstRead() before! - /// Each slot is 2048µs/353mm wide. + /// Each slot is 2048us/353mm wide. /// @param slotIdx slot 0..31 int getANNSlotDataFromRawBuffer(int slotIdx) const { return (static_cast<int>(m_rawBuffer[slotIdx+4])); } - /// Reads all data from start to stop register in one go and store it in class internal buffer. + /// Reads all data from start to stop register in one go and stores it in a class internal buffer. See getXXXXXFromRawBuffer_us() functions. /// - reg 0x00: SW Revision /// - reg 0x01: light sensor (SRF08 only) /// - reg 0x02+0x03: range high+low byte