×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Programming I2C Serial EEPROM 24CXX

Programming I2C Serial EEPROM 24CXX

Programming I2C Serial EEPROM 24CXX

(OP)
Hi,

I am experimenting with a programmer for 24CXX type serial EEPROMs, I developed a programmer interface for the serial port (I don't want to use the parallel port which is a common preference) on the PC, I have tested this programmer using PONYPRO program and works just fine, the thing is that just to better understand how this type of devices work I want to develop my own application using Visual Basic and the MSCOMM control. The data sheet of a 24CXX suggest that for a READ the following sequence must be done:

START 1010AAA0 N HHHHHHHH N LLLLLLLL N START 1010AAA1 N
          210    76543210   76543210         76543210
RRRRRRRR N STOP

where R indicates the PC reading a bit.

Frankly, I know how to send or recive data on Visual Basing through the MSCOMM, but I don't know how to control it to send such a sequence described before in which a for instance to make a SATRT condition you must make a transition from High to Low of SDA while SCL is High.

So if someone has experimented using Visual Basic/MSCOMM and the Pc'Serial Port to program a 24CXX please giev a hint.

The circuit is below just try to make it look right by copying and pasting it on a notepad document.

Thank you very much-

                100n| |    
                  --| |--    
                 |     | |  |                               PC SIDE
                 |         |    LM7805                       SERIAL PORT    
        24CXX         |        \ /  ----------                  1N4148        RS232
         ----------  |       |          |                      | /|             -
          --|A0    VCC|------------|Vout   Vin|----------------------|< |---------|4| DB9 - DTR
         |  |        |jumper   |  |    GND   |       |   |      |   | \|       |    -
          --|A1    WP |-o  o-   |+  ----------     + |   |      |           |
         |  |       |  J1  | ---       |              --- ---     |           |
          --|A2    SCL|----  | ---         \ /         --- ---     |      | /|       |    -
         |  |       |    | |  |47u        47u|___|100n   ---|< |-----|---|6| DB9 - DSR
          --|GND    SDA|--  |  --|                   |          | \|    |  | |  -
         |   ----------   | |   \ /              \ /            |  | |
        \ /              | |                        |  | |  -
                  | |                        |  |  -|7| DB9 - RTS    
                  | |            4.7K            |  |    -
                  |  ---------------------/\/\/\--------------------   |
                  |            |                   |
                  |            |    4.7K               |
                  |-----------------| -----/\/\/\----------------------
                  |        |    |  
                  |        |      ---´
                  |           ---´   ´ ^                    -    
                  |          ´ ^     /___\                    ---|5| DB9 - GND
                  |          /___\    |4.7V                   |    -
                  |        |4.7V   |                   |
                  |        |       |                   |    
                  |           \ /     \ /                  \ /
                  |
                  |                                -
                   --------------------------------------------------------|8| DB9 - CTS
                                            -

RE: Programming I2C Serial EEPROM 24CXX

Your drawing is unreadable on my computer.
Can you use MSCOMM to set the control bits individually?  You more or less need to drive these bits as a parallel port.

Are there any utilities in VB to drive the printer port?  It might be easier.  The levels are already at 5 volts, and they are open collector.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources