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Re: HMC5883L Magnetometer chip Possibilities.
you can do a similar thing with y axis too ,
my routine will give the same result as the scale offset method its just much quicker and simpler.
don't forget the ATN result is in radians so deg = atnresult*360/256
I suspect that without using floats all round for these calcs the resulting resolution may be a little disappointing , but its worth a look
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Re: HMC5883L Magnetometer chip Possibilities.
Thank you for reading
Hi Have tried suggestions...
But now the I2CRead command is failing on on the HIGHBYE and LOWBYTE locations, I think it due to the X declare beng a Byte now not a Word.
My solution was to just use the MSB part and comment out the LSB putting the result into X.
This compiled OK but raw numbers refuse to move.... \i guess it needs the whole word.
HELP !!
BR
Andy
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Re: HMC5883L Magnetometer chip Possibilities.
the i2c read uses the word var readingx the byte var x is the "scaled" result from that readingBut now the I2CRead command is failing on on the HIGHBYE and LOWBYTE locations, I think it due to the X declare beng a Byte now not a Word
if you can't work that out post your code so we can see what your doing {in code tags }
Last edited by richard; - 31st December 2014 at 10:57. Reason: edit
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Re: HMC5883L Magnetometer chip Possibilities.
Hi Richard
Thank you for reply... Here is code to date.... With most recent error.
Excuse my issues I am still learning....Code:'**************************************************************** '* Name : COMPASS_818.BAS * '* Author : [select VIEW...EDITOR OPTIONS] * '* Notice : Copyright (c) 2014 [select VIEW...EDITOR OPTIONS] * '* : All Rights Reserved * '* Date : 24/08/2014 * '* Version : 1.0 * '* Notes : * '* : * '**************************************************************** ' LCD should be connected as follows: ' LCD PIC ' DB4 PortA.0 ' DB5 PortA.1 ' DB6 PortA.2 ' DB7 PortA.3 ' RS PortA.4 (add 4.7K (10k)pullup resistor to 5 volts) ' E PortB.3 ' RW Ground ' Vdd 5 volts ' Vss Ground ' Vo 5K potentiometer (or ground) ' DB0-3 No connect adcon1 = 7 ' Turns Analogs off DEFINE OSC 12 'Set oscillator in MHz 'OSCCON = $70 DEFINE LCD_EREG PORTB DEFINE LCD_EBIT 6 DEFINE LCD_RSREG PORTB DEFINE LCD_RSBIT 7 ' -----[ Pins/Constants/Variables ]------------------------------------------- SDA var portb.1 'transceives to/from SDA SCL var portb.4 'sends clock pulses WRITE_DATA CON $3C 'Used to perform a Write operation READ_DATA CON $3D 'Used to perform a Read operation MODE CON $02 'Read/Write Register, Selects the operating mode. Default = Single measurement 'Send $3C $02 $00 on power up to change to continuous measurement mode. X_MSB CON $03 'Read Register, Output of X MSB 8-bit value. X_LSB CON $04 'Read Register, Output of X LSB 8-bit value. Z_MSB CON $05 'Read Register, Output of Z MSB 8-bit value. Z_LSB CON $06 'Read Register, Output of Z LSB 8-bit value. Y_MSB CON $07 'Read Register, Output of Y MSB 8-bit value. Y_LSB CON $08 'Read Register, Output of Y LSB 8-bit value. Cont_Mode CON $0 SCALEFACTOR CON 4081 'SCALEFACTOR = 65536 * (255/4095) = 4081 SCALEOFFSET CON 2048 'The output range of the HMC5883L is -2048 to 2047; therefore to get a 0 (LOWRANGE)to 4095 range 'to 4095 (HIGHRANGE) range 2048 must be added to the sensor value. ATNFACTOR CON 127 'the ATN function input range is -127 TO 127. In order to get the positive scaled range of '0 to 255 into the range of -127 to 127, 127 must be subtracted. LOWRANGE CON 0 'see SCALEOFFSET HIGHRANGE CON 4095 'see SCALEOFFSET X VAR byte 'x sensor measured value Y VAR byte 'y sensor measured value Z VAR byte 'z sensor measured value READX VAR WORD READY VAR WORD READZ VAR WORD brads VAR Word 'angle in brads degr VAR Word 'angle in degrees azimuth VAR Word 'value calculated using X ATN -Y ' -----[ Main Routine ]------------------------------------------------------- PAUSE 500 ' Give sensor needed power up time I2CWRITE SDA,SCL,WRITE_DATA,MODE,[Cont_Mode] ' Send continuous output command DO GOSUB GetRawReading ' Get RAW Compass reading 'RAW X,Y,Z data... Lcdout $fe, 1 ' Clear LCD screen Lcdout "X=",SDEC X ," Y=",SDEC Y Lcdout $fe, $C0, "Z=",SDEC Z 'DEBUG HOME, "RAW X,Y,Z", CR 'DEBUG "X = ",11, SDEC x, CR 'DEBUG "Y = ",11, SDEC y, CR 'DEBUG "Z = ",11, SDEC z, CR ' Print angle 'DEBUG CR 'Calculate Azimuth GOSUB GetAzimuth 'Calculated Heading in Degrees brads = azimuth 'get angle degr = brads */ 361 'convert to degrees 'DEBUG CR 'DEBUG "Heading in NORTH, EAST, SOUTH, and WEST clockwise from NORTH:", CLREOL, CR, CR 'DEBUG "Degree " ,11, SDEC degr, CR 'display degrees GOSUB GetHeading LOOP ' -----[ Subroutines ]-------------------------------------------------------- GetRawReading: 'Compass module subroutine PAUSE 400 'Wait for new data to become available I2CREAD SDA,SCL,READ_DATA, X_MSB,[X.HIGHBYTE] 'Read the data starting at x_msb 3 I2CREAD SDA,SCL,READ_DATA ,X_LSB,[X.lowBYTE] 'Do the same for Z and Y: I2CREAD SDA,SCL,READ_DATA, Z_MSB,[Z.HIGHBYTE] I2CREAD SDA,SCL,READ_DATA ,Z_LSB,[Z.lowBYTE] I2CREAD SDA,SCL,READ_DATA, Y_MSB,[Y.HIGHBYTE] I2CREAD SDA,SCL,READ_DATA ,Y_LSB,[Y.lowBYTE] RETURN GetAzimuth: 'The output range of the HMC5883L is -2048 to 2047 and the input range of the ATN function 'is -127 to 127. I used the method to scale the output to the input discribed in Parallax's Smart 'Sensors Student Guide v1 starting on page 76. 'SCALEFACTOR = 65536 * (255/4095) = 4081 'SCALEOFFSET = 2048 'ATNFACTOR = 127 'LOWRANGE = 0 'HIGRANGE = 4095 (2048 + 2047 = 4095) 'x = x + SCALEOFFSET 'x = (x MIN LOWRANGE MAX HIGHRANGE) ** SCALEFACTOR - ATNFACTOR 'y = y + SCALEOFFSET 'y = (y MIN LOWRANGE MAX HIGHRANGE) ** SCALEFACTOR - ATNFACTOR x = readx >>4 Y = readY >>4 'Z = readZ >>4 'DEBUG "SCALED X,Y", CR 'DEBUG "X = ",11, SDEC x, CR 'DEBUG "Y = ",11, SDEC y, CR azimuth = x ATN -y 'DEBUG "Azimuth ",11, SDEC azimuth, CR ' display scaled azimuth 'DEBUG "COS Azimuth ",11, SDEC COS azimuth, CR ' display scaled cos azimuth RETURN GetHeading: 'Gives a heading in North, South, East and West. IF degr = 90 THEN 'DEBUG "NORTH" 'DEBUG CLREOL ENDIF IF degr = 0 THEN 'DEBUG "EAST" 'DEBUG CLREOL ENDIF IF degr = 270 THEN 'DEBUG "SOUTH" 'DEBUG CLREOL ENDIF IF degr = 180 THEN 'DEBUG "WEST" 'DEBUG CLREOL ENDIF RETURN
BR
Andy
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Re: HMC5883L Magnetometer chip Possibilities.
this should fix the i2c errors
Code:'**************************************************************** '* Name : COMPASS_818.BAS * '* Author : [select VIEW...EDITOR OPTIONS] * '* Notice : Copyright (c) 2014 [select VIEW...EDITOR OPTIONS] * '* : All Rights Reserved * '* Date : 24/08/2014 * '* Version : 1.0 * '* Notes : * '* : * '**************************************************************** ' LCD should be connected as follows: ' LCD PIC ' DB4 PortA.0 ' DB5 PortA.1 ' DB6 PortA.2 ' DB7 PortA.3 ' RS PortA.4 (add 4.7K (10k)pullup resistor to 5 volts) ' E PortB.3 ' RW Ground ' Vdd 5 volts ' Vss Ground ' Vo 5K potentiometer (or ground) ' DB0-3 No connect adcon1 = 7 ' Turns Analogs off DEFINE OSC 12 'Set oscillator in MHz 'OSCCON = $70 DEFINE LCD_EREG PORTB DEFINE LCD_EBIT 6 DEFINE LCD_RSREG PORTB DEFINE LCD_RSBIT 7 ' -----[ Pins/Constants/Variables ]------------------------------------------- SDA var portb.1 'transceives to/from SDA SCL var portb.4 'sends clock pulses WRITE_DATA CON $3C 'Used to perform a Write operation READ_DATA CON $3D 'Used to perform a Read operation MODE CON $02 'Read/Write Register, Selects the operating mode. Default = Single measurement 'Send $3C $02 $00 on power up to change to continuous measurement mode. X_MSB CON $03 'Read Register, Output of X MSB 8-bit value. X_LSB CON $04 'Read Register, Output of X LSB 8-bit value. Z_MSB CON $05 'Read Register, Output of Z MSB 8-bit value. Z_LSB CON $06 'Read Register, Output of Z LSB 8-bit value. Y_MSB CON $07 'Read Register, Output of Y MSB 8-bit value. Y_LSB CON $08 'Read Register, Output of Y LSB 8-bit value. Cont_Mode CON $0 'SCALEFACTOR CON 4081 'SCALEFACTOR = 65536 * (255/4095) = 4081 'SCALEOFFSET CON 2048 'The output range of the HMC5883L is -2048 to 2047; therefore to get a 0 (LOWRANGE)to 4095 range 'to 4095 (HIGHRANGE) range 2048 must be added to the sensor value. 'ATNFACTOR CON 127 'the ATN function input range is -127 TO 127. In order to get the positive scaled range of '0 to 255 into the range of -127 to 127, 127 must be subtracted. 'LOWRANGE CON 0 'see SCALEOFFSET 'HIGHRANGE CON 4095 'see SCALEOFFSET X VAR byte 'x sensor measured value Y VAR byte 'y sensor measured value Z VAR byte 'z sensor measured value READX VAR WORD READY VAR WORD READZ VAR WORD brads VAR Word 'angle in brads degr VAR Word 'angle in degrees azimuth VAR Word 'value calculated using X ATN -Y ' -----[ Main Routine ]------------------------------------------------------- PAUSE 500 ' Give sensor needed power up time I2CWRITE SDA,SCL,WRITE_DATA,MODE,[Cont_Mode] ' Send continuous output command DO GOSUB GetRawReading ' Get RAW Compass reading 'RAW X,Y,Z data... Lcdout $fe, 1 ' Clear LCD screen Lcdout "X=",SDEC X ," Y=",SDEC Y Lcdout $fe, $C0, "Z=",SDEC Z 'DEBUG HOME, "RAW READX,READY,READZ", CR 'DEBUG "X = ",11, SDEC x, CR 'DEBUG "Y = ",11, SDEC y, CR 'DEBUG "Z = ",11, SDEC z, CR ' Print angle 'DEBUG CR 'Calculate Azimuth GOSUB GetAzimuth 'Calculated Heading in Degrees brads = azimuth 'get angle degr = brads */ 361 'convert to degrees 'DEBUG CR 'DEBUG "Heading in NORTH, EAST, SOUTH, and WEST clockwise from NORTH:", CLREOL, CR, CR 'DEBUG "Degree " ,11, SDEC degr, CR 'display degrees GOSUB GetHeading LOOP ' -----[ Subroutines ]-------------------------------------------------------- GetRawReading: 'Compass module subroutine PAUSE 400 'Wait for new data to become available I2CREAD SDA,SCL,READ_DATA, X_MSB,[READX.HIGHBYTE] 'Read the data starting at x_msb 3 I2CREAD SDA,SCL,READ_DATA ,X_LSB,[READX.lowBYTE] 'Do the same for Z and Y: I2CREAD SDA,SCL,READ_DATA, Z_MSB,[READZ.HIGHBYTE] I2CREAD SDA,SCL,READ_DATA ,Z_LSB,[READZ.lowBYTE] I2CREAD SDA,SCL,READ_DATA, Y_MSB,[READY.HIGHBYTE] I2CREAD SDA,SCL,READ_DATA ,Y_LSB,[READY.lowBYTE] RETURN GetAzimuth: 'The output range of the HMC5883L is -2048 to 2047 and the input range of the ATN function 'is -127 to 127. I used the method to scale the output to the input discribed in Parallax's Smart 'Sensors Student Guide v1 starting on page 76. 'SCALEFACTOR = 65536 * (255/4095) = 4081 'SCALEOFFSET = 2048 'ATNFACTOR = 127 'LOWRANGE = 0 'HIGRANGE = 4095 (2048 + 2047 = 4095) 'x = x + SCALEOFFSET 'x = (x MIN LOWRANGE MAX HIGHRANGE) ** SCALEFACTOR - ATNFACTOR 'y = y + SCALEOFFSET 'y = (y MIN LOWRANGE MAX HIGHRANGE) ** SCALEFACTOR - ATNFACTOR x = readx >>4 Y = readY >>4 'Z = readZ >>4 'DEBUG "SCALED X,Y", CR 'DEBUG "X = ",11, SDEC x, CR 'DEBUG "Y = ",11, SDEC y, CR azimuth = x ATN -y 'DEBUG "Azimuth ",11, SDEC azimuth, CR ' display scaled azimuth 'DEBUG "COS Azimuth ",11, SDEC COS azimuth, CR ' display scaled cos azimuth RETURN GetHeading: 'Gives a heading in North, South, East and West. IF degr = 90 THEN 'DEBUG "NORTH" 'DEBUG CLREOL ENDIF IF degr = 0 THEN 'DEBUG "EAST" 'DEBUG CLREOL ENDIF IF degr = 270 THEN 'DEBUG "SOUTH" 'DEBUG CLREOL ENDIF IF degr = 180 THEN 'DEBUG "WEST" 'DEBUG CLREOL ENDIF RETURN
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Re: HMC5883L Magnetometer chip Possibilities.
to get the azimuth result in degrees
azimuth = ( x ATN -y) */ 360
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Re: HMC5883L Magnetometer chip Possibilities.
Not important at this point but you have East and North reversed.
I'm try to do the same thing with HMC5983, I can read data which seems reasonable ie very different and repeatable for the four directions, but I can't seem to produce a heading less than about 180.
Typical raw numbers
x y N 215 -176 E -76 7 S -265 -287 W -12 -474
Seems like an awful lot of negative numbers? I wonder if I've killed it?
George
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