Trouble talking to HMC6364 Compass

CountMurphy · 2013-04-05 18:16

I recently purchased this chip in hopes it would be simple to interface with the propeller. The documentation said in order to use the chip, I'd have to:

[FONT=sans-serif]
1. [/FONT][FONT=sans-serif]Appl[/FONT][FONT=sans-serif]y power to the VDD pins (nominally[/FONT]

[FONT=sans-serif]2.[/FONT][FONT=sans-serif]Wait at least 5[/FONT][FONT=sans-serif]00[/FONT][FONT=sans-serif] milli[/FONT][FONT=sans-serif]-[/FONT][FONT=sans-serif]seconds for device initialization. The HMC6343 is in the default Run Mode.[/FONT]


[FONT=sans-serif]3.[/FONT] [FONT=sans-serif]Send 0x32 and 0x50 to command the Heading and Tilt Data to be clocked out next.[/FONT]


[FONT=sans-serif]4.[/FONT][FONT=sans-serif]Wait at least 1 milli[/FONT][FONT=sans-serif]-[/FONT][FONT=sans-serif]second[/FONT] [FONT=sans-serif]to allow the HMC6343 to process the comm[/FONT][FONT=sans-serif]and.[/FONT]


[FONT=sans-serif]5.[/FONT][FONT=sans-serif]Send  0x33  and  clock  back  six  more  response  Bytes  from  the  HMC6343.  These  will  be  the  Heading,  Pitch  and [/FONT]
[FONT=sans-serif]Roll  Byte  pairs[/FONT][FONT=sans-serif];  binary  format  in  tenths  of  a  degree[/FONT] [FONT=sans-serif]with  2s  compliment  on  pitch  and  roll  angles.  (0  to  3600 [/FONT][FONT=sans-serif]heading, [/FONT]
[FONT=sans-serif]±900 pitch, and ±9[/FONT][FONT=sans-serif]00 roll)[/FONT]


[FONT=sans-serif]6.[/FONT][FONT=sans-serif]Repeat [/FONT][FONT=sans-serif]steps 3 [/FONT][FONT=sans-serif]-[/FONT][FONT=sans-serif]5 [/FONT][FONT=sans-serif]every 2[/FONT][FONT=sans-serif]00 milli[/FONT][FONT=sans-serif]-[/FONT][FONT=sans-serif]seconds or longer to ge[/FONT][FONT=sans-serif]t fresh data from the default 5[/FONT]Hz update rate

Sounds simple right? Yet no matter what I do I only am reading "0" as an output. Could someone please proof read my spin code and let me know if I am doing something really dumb?

CON
  _clkmode=xtal1+pll16x
  _xinfreq=5_000_000

  device=$32 <<1

obj
  serial : "Simple_Serial"
  SN : "Simple_Numbers"
  i2c : "Basic_I2C_Driver"


pub main|X
  serial.init(1,30,4800)
  waitcnt(clkfreq+cnt)
  i2c.Initialize(22)'set our clock plus +1 for sda
  waitcnt(clkfreq+cnt)
  repeat
    i2c.start(22)
    i2c.Write(22,device)
    i2c.Write(22,$50) 'get tilt heading info!
    i2c.stop(22)
    waitcnt(clkfreq/1000 + cnt)     'wait milisecond
    i2c.start(22)
    i2c.Write(22,$33)
    X:=(i2c.Read(22,i2c#ACK) << 8) | (i2c.Read(22,i2c#ACK))
    serial.str(SN.dec(X))
    i2c.stop(22)
    serial.str(string("   "))
    waitcnt(clkfreq + cnt)

I know there are objects to read this chip in the object exchange already, but I couldn't get them working either. Thanks in advance!

Using Basic I2C Routines Version 1.3

Leon · 2013-04-06 01:51

Schematic?

CountMurphy · 2013-04-06 09:47

Leon wrote: »

Schematic?

http://dlnmh9ip6v2uc.cloudfront.net/datasheets/Sensors/Magneto/HMC6343_v13.pdf

As for how its hooked up, scl is pin 22, and sda is pin 23. Data sheet is here: http://www51.honeywell.com/aero/common/documents/myaerospacecatalog-documents/Missiles-Munitions/HMC6343.pdf

CountMurphy · 2013-04-07 15:54

As of now if the code above is run with the most current i2c Driver it prints out :

0   775   7   1   0   0   7   1   0   0   7   257   1   256   0   1   257   257   1   0   0   0   1   0  .......

Now it prints this with out me touching the compass (stays stationary) so I know these are not proper heading values. If I run the code above using Tim Moore's clock stretching i2c driver I get all zeros. If it helps any I am using this breakout from spark fun https://www.sparkfun.com/products/8656 (so I am assuming I dont need pull up resistors since it works as is with an arduino).

CountMurphy · 2013-04-07 16:41

I've also started playing more with Tim's HMC6343 object code (found here: http://obex.parallax.com/objects/372/) in hoping I could at the very least get that working. Here is my go at it:

CON
  _clkmode=xtal1+pll16x
  _xinfreq=5_000_000

  device=$32 <<1

obj
  serial : "Simple_Serial"
  uarts : "Simple_Serial"
  SN : "Simple_Numbers"
  i2c : "Basic_I2C_Driver"
   i2cObject     : "basic_i2c_driver"                    '0 COG
  hmc           : "hmc6343object"
VAR
  long i2cSCL

pub main|X,Y,Z
  i2cSCL := 22
  ' setup i2cObject
  i2cObject.Initialize(i2cSCL)
  uarts.init(1,30,4800)
  repeat
    hmc.GetHeading(i2cSCL, device,@X,@Y,@Z)
    uarts.str(string("Heading XYZ: "))
    if X < 0
      uarts.str(string("-"))
    uarts.str(SN.dec(||X/10))
    uarts.str(string("."))
    uarts.str(SN.dec(||X//10))
    uarts.str(string(" "))
    if Y < 0
      uarts.str(string("-"))
    uarts.str(SN.dec((||Y)/10))
    uarts.str(string("."))
    uarts.str(SN.dec((||Y)//10))
    uarts.str(string(" "))
    if Z < 0
      uarts.str(string("-"))
    uarts.str(SN.dec(||Z/10))
    uarts.str(string("."))
    uarts.str(SN.dec(||Z//10))
    'uarts.tx(0,13)

This code returns

Heading XYZ: 25.7 25.7 25.7

only when tilted. if i move the compass, I get nothing but zeros again. I dont know what I am doing wrong, and the device itself works with my arduino uno, so I know the chip isn't bad. I've also tried using different pins on my prop for the i2c communication but that didn't give me different results either.

Trouble talking to HMC6364 Compass

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