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connecting serial led display driver — Parallax Forums

connecting serial led display driver

ArchiverArchiver Posts: 46,084
edited 2004-01-09 18:48 in General Discussion
Hi,

I'm new to Basicstamps and would like to connect a serial led display
B25M04N (Opto Images - Nexus Machines). 4 digits.
The device has a data line and a clock line for data input.
36 bits of data have to be set on the data line.
The clock line expects a frequency of 500 kHz.
Can I use the I2C bus and commands of the basic stamp ? or do I need
another approach.

Regards,

Eric Messens

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2004-01-09 16:44
    At 10:48 AM 1/9/04 +0000, emessens wrote:
    >Hi,
    >
    >I'm new to Basicstamps and would like to connect a serial led display
    >B25M04N (Opto Images - Nexus Machines). 4 digits.
    >The device has a data line and a clock line for data input.
    >36 bits of data have to be set on the data line.
    >The clock line expects a frequency of 500 kHz.
    >Can I use the I2C bus and commands of the basic stamp ? or do I need
    >another approach.
    >
    >Regards,
    >
    >Eric Messens

    Eric -

    The datasheet for that display makes no claim to be I2C compatible, so I'd just
    use the SHIFTOUT directive. Additionally, the 500 KHz speed is a MAXIMUM speed,
    and not something I suspect you'll have to worry about.

    Regards,

    Bruce Bates
  • ArchiverArchiver Posts: 46,084
    edited 2004-01-09 18:48
    You should be able to use SHIFTOUT to talk with the device. Thankfully,
    SHIFTOUT is flexible and can deal with the bit positions of the display.
    I don't have a display (yet), but think this will work:

    Update_BxxMO4:
    LOW CE
    SHIFTOUT Dpin, Cpin, LSBFIRST, [noparse][[/noparse]1\1, digit0, digit1, digit2, digit3,
    annun\3]
    HIGH CE
    RETURN

    '1\1' at the beginning of the stream is the start bit.

    The digit segments are mapped like this: Bit0 = A, Bit1 = B, ... Bit7 =
    DP. A "1" in any bit position lights the segment.

    The variable annun is for the optional annuciators; AN1 = Bit0, AN2 =
    Bit1 (Bits 2 and higher are not used, but the Bit2 is expected for 36
    total bits).

    -- Jon Williams
    -- Applications Engineer, Parallax
    -- Dallas Office



    Original Message
    From: emessens [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=RH5LmjxKsArGNeeSPr_TwSQ8H1S0-FfwLKnjftnFqUNvBql4_sTQnvN0fgtIbsbeNi3KwyAyuNk4GrnlODJ998AZqn5NRXM]eric.messens@o...[/url
    Sent: Friday, January 09, 2004 4:48 AM
    To: basicstamps@yahoogroups.com
    Subject: [noparse][[/noparse]basicstamps] connecting serial led display driver


    Hi,

    I'm new to Basicstamps and would like to connect a serial led display
    B25M04N (Opto Images - Nexus Machines). 4 digits.
    The device has a data line and a clock line for data input.
    36 bits of data have to be set on the data line.
    The clock line expects a frequency of 500 kHz.
    Can I use the I2C bus and commands of the basic stamp ? or do I need
    another approach.

    Regards,

    Eric Messens



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