Barometer Pressure Module HOPE HP03


+ Reply to Thread
Results 1 to 14 of 14
  1. #1
    Join Date
    Nov 2007
    Location
    South-West of Australia. A small town called Denmark. 'Where the forest meets the sea.'
    Posts
    136

    Default Barometer Pressure Module HOPE HP03

    I 'm after some advice on wiring up the HP03 chip.

    The device has 6 pins:
    1. Vss
    2. Vdd
    3. MCLK. Master clock input, 32768Hz
    4. XCLR. ADC re-set
    5. SDA. IIC comms, data
    6. SCL. IIC comms, clock

    First question - the wiring diagram in the spec sheet shows the device connected to a MCU with a 32768Hz Xtal i.e. both the MCU and the HP03 share the same clock frequency. Is this necessary? Or, can the MCU run at, say 20MHz and the 32768Hz be provided to the device from another source?

    Second Question - Vdd is specified as 2.2 - 3.6 Volts. Vdd Absolute max is 4 Volts. The ratings for the other pins are not given in the spec sheet. Are they '5 Volt tolerant' ?

    Regards Bill Legge

  2. #2
    Join Date
    Dec 2005
    Posts
    1,073

    Default

    Quote Originally Posted by Bill Legge View Post
    Or, can the MCU run at, say 20MHz and the 32768Hz be provided to the device from another source?
    The IC clock is usually supplied from a pin on the MCU.
    Quote Originally Posted by Bill Legge View Post
    The ratings for the other pins are not given in the spec sheet. Are they '5 Volt tolerant' ?
    Not likely. Always assume they are not unless explicitly stated in the datasheet.

  3. #3
    Join Date
    Nov 2007
    Location
    South-West of Australia. A small town called Denmark. 'Where the forest meets the sea.'
    Posts
    136

    Default I2c

    DHOUSTON

    Thanks for you comments.

    1. The normal I2C clock is the SCL pin - and I agree it is driven by the PIC MCU. The 32768 Hz is needed by the MCLK pin and does something for the A to D process.

    2. The question of the 5 volt tolerance of the chip - after a day of digging round on the web - seems to agree with your view. Philips has a good application note on bi-directional level shifting for the I2C bus (AN97055). I'll give it a go using 2N7000 MOSFETs

    Regards Bill Legge

  4. #4
    Join Date
    May 2004
    Location
    NW France
    Posts
    3,578

    Wink

    Hi, Bill

    I'd recommend you to have a look to Intersema MS 5534 sensor ...

    If the pinout is not the same, internal diagram, functionning principle and features are very-very-very close to the HP 03 ... ( no, i didn't say it ... lol )

    Also you will find ANs and tricks on the Intersema site :
    http://www.intersema.ch

    Alain
    ************************************************** ***********************
    Why insist on using 32 Bits when you're not even able to deal with the first 8 ones ??? ehhhhhh ...
    ************************************************** ***********************
    IF there is the word "Problem" in your question ...
    certainly the answer is " RTFM " or " RTFDataSheet " !!!
    *****************************************

  5. #5
    Join Date
    Dec 2005
    Posts
    1,073

    Default

    Quote Originally Posted by Bill Legge View Post
    1. The normal I2C clock is the SCL pin - and I agree it is driven by the PIC MCU. The 32768 Hz is needed by the MCLK pin and does something for the A to D process.
    In this case I'm sure you can use separate clock sources - there's no reason why the ADC clock would need to be synced with the MCU clock. You can probably use the 16F88's PWM to supply the ADC clock. It would simplify things to run the PIC at 3.3V.

    How much does the sensor cost? Where can you buy them?
    Last edited by dhouston; - 10th June 2009 at 16:06.

  6. #6
    Join Date
    May 2004
    Location
    NW France
    Posts
    3,578

    Wink

    Hi, Dave

    I have a Barometer/Altimeter/Tempmeter/Clock with a 5534, running here ...

    The Pic and the sensor are powered from a 3v regulator ( ICL 7663 )
    32,7 Khz clock is derived from the PWM module of the PIC ( both 16F876 ( LCD 2x20 ) or 18F452 ( GLCD 122x32 ) projects ... )

    The only thing to remember is to have a STRONG Decoupling of the sensor supply : 47F + Tantalum is recommended for reliable work.

    Alain
    ************************************************** ***********************
    Why insist on using 32 Bits when you're not even able to deal with the first 8 ones ??? ehhhhhh ...
    ************************************************** ***********************
    IF there is the word "Problem" in your question ...
    certainly the answer is " RTFM " or " RTFDataSheet " !!!
    *****************************************

  7. #7
    Join Date
    Nov 2007
    Location
    South-West of Australia. A small town called Denmark. 'Where the forest meets the sea.'
    Posts
    136

    Default I2C Barometer

    Thanks for the infirmation.

    It seems that the pins are NOT 5 Volt tolerant and I either:

    1. Use the bi-directional level converting circuit given in the Philips application note, or
    2. Run the MCU at 3 Volts.

    Thanks for the idea of using the HPWM signal for the A/D clock.

    The HP03 chip (mounted on a carrier with 0.1 inch pins) is available from Ocean Controls here in Australia for about $AUS 25 ($US 20): http://www.oceancontrols.com.au

    Thanks Bill Legge

  8. #8
    Join Date
    Nov 2007
    Location
    South-West of Australia. A small town called Denmark. 'Where the forest meets the sea.'
    Posts
    136

    Default 5534 Barometer

    Alain of Acertronics

    Alain,

    Thanks for your post. Any chance of seeing your program for the 5534. Particularly the I2C comms bit?

    I've got mine running but the calibration coefficients are nothing like the published example. I'm wondering if:

    1. My code is wrong, or
    2. My level conversion is wrong?

    Regards Bill Legge
    In Australia

  9. #9
    Join Date
    Nov 2007
    Location
    South-West of Australia. A small town called Denmark. 'Where the forest meets the sea.'
    Posts
    136

    Default HP03 Barometer

    Alain of Acertronics

    Don't bother with the code - I've just got mine working.

    Pull-up resistor on the SCL line was poorly connected.

    The bi-directional level conversion described in the Philips application note works fine with a 2N7000 MOSFET.

    Regards Bill Legge

  10. #10
    Join Date
    Dec 2005
    Posts
    1,073

    Default

    Quote Originally Posted by Bill Legge View Post
    Thanks for the infirmation.

    It seems that the pins are NOT 5 Volt tolerant and I either:

    1. Use the bi-directional level converting circuit given in the Philips application note, or
    2. Run the MCU at 3 Volts.
    There are some simpler methods than those in the Philips app note. See Interfacing to Lower Voltage Devices on pp10-11 of http://www.zbasic.net/appNotes/AN213.pdf. The transistor (e.g. 2N3904) circuits of FIG 15 will work for nearly anything.
    Last edited by dhouston; - 11th June 2009 at 13:21.

  11. #11

    Default 5 V to 3v3 with Intersema sensors

    I have used hundreds of intersema sensors for atmospheric pressure and 5 - 10 atmosphere applications over the last 5 years. I use a simple resistive divider for the 5>3v3 level conversion. In the 3v3>5 direction I just directly connect.

    I run the PIC at 5 volts and the Intersems 5534 at 3v3 from an LDO 3 volt regulator. From PIC to 5534 I have 2k2 with 3k3 to ground at the 5534 end for signals to the 5534 DIn, SClk and MClk. DOut, from the 5534, I just hook directly to the PIC. Yes that means a 3v3 signal into a 5 volt PIC (RC.3). It works.

    The HOPE is definitely a knock off of the Intersema product. Has anyone done any side by side accuracy tests? Pricing looks slightly in favour of the HOPE unit but I'm not going to make the change unless the accuracy is at least as good as the Swiss Intersema units.

    Cheers
    BrianT

  12. #12
    Join Date
    Nov 2007
    Location
    South-West of Australia. A small town called Denmark. 'Where the forest meets the sea.'
    Posts
    136

    Default HOPE Circuit 3/5 Volts

    The circuit on the attached JPEG has been running well. At $25 a go for the HOPE HP03 I'm reluctant to risk the direct connection between the 3.3 and 5 Volt chips.

    Regards Bill legge
    Attached Images Attached Images  

  13. #13
    Join Date
    Jun 2005
    Location
    West Australia
    Posts
    101

    Default Zener protection

    Hi Bill,

    I use the same setup as BrianT however also add a 3v zener to ground on the data pin (cathode) and a series 220R resistor going to the 5v PIC, just in case...

    Regards,
    Bill

  14. #14
    quipaqua's Avatar
    quipaqua Guest

    Default

    Salut les gars, Im a newbie. Nice participer ce forum.

Similar Threads

  1. Version Control
    By btaylor in forum mel PIC BASIC Pro
    Replies: 33
    Last Post: - 16th October 2011, 18:12
  2. Replies: 1
    Last Post: - 27th July 2008, 07:14

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts