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FM24C64 I2C help — Parallax Forums

FM24C64 I2C help

nick bernardnick bernard Posts: 329
edited 2006-11-28 14:54 in General Discussion
i'm have trouble with my read write routines with my first I2C external memorty application.

i got the code from the sx/b help file but its not working.

any help?
tech doc
http://www.ramtron.com/lib/literature/datasheets/FM24C64ds_r3.0.pdf

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Post Edited (nick bernard) : 11/14/2006 9:34:41 PM GMT
SXB
SXB
fram test.SXB
3K

Comments

  • Dave HeinDave Hein Posts: 6,347
    edited 2006-11-14 22:28
    The code looks OK to me. The only thing I see is that you are using a device address of 1. This should work if you tied the A0 pin high, and the A1 and A2 pins low.

    Dave
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2006-11-15 13:26
    Where did you get the FRAM?
    I have been hoping to try them out.

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    "If you want more fiber, eat the package.· Not enough?· Eat the manual."········
    ···················· Tropical regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan
  • nick bernardnick bernard Posts: 329
    edited 2006-11-15 14:20
    actually i have 2 frams on 1 i2c network addressed 0 and 1
    mouser. they have a few readily available.

    arg so i have a hardware problem!

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    engineer, fireman, bowler, father, WoW addict [noparse];)[/noparse]
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2006-11-15 14:32
    If you have a Propeller, the I2C driver is included as an object and will easily confirm that the FRAMs are okay.

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    "If you want more fiber, eat the package.· Not enough?· Eat the manual."········
    ···················· Tropical regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan
  • nick bernardnick bernard Posts: 329
    edited 2006-11-16 14:02
    i have a demo board but the frams are soic-8.

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  • Dave HeinDave Hein Posts: 6,347
    edited 2006-11-16 14:55
    Nick,

    Does FRAM 0 work OK? Can you remove one of the FRAM chips and verify whether the other works by itself? Does your circuit look like the one in the spec sheet where you have external 1.8K pull-up resistors on the clock and data lines? It would be useful if you could post your circuit diagram.

    Dave
  • LoopyBytelooseLoopyByteloose Posts: 12,537
    edited 2006-11-16 15:59
    Are you having touble with getting an interface?

    I have purchased SOIC-20 adapter boards·and cut them in half with a small hacksaw.· Then I finish the sides with emery paper.· The result is two boards to adapt SOIC-8 to 0.1pin spacing.

    This worked out nicely from me because the SOIC-8 devices are light sensors and I could not do the 'dead bug' trick.· In the 'dead bug'·trick, you turn the Soic-8 upside-down and solder each lead to an empty 8 Pin DIP socket with some 30 guage wire wrap wire.

    I am beginning to not fear surface mount.· I even was able to bridge a 0.1uf capacitor between Vss and Vdd·on the halved adapter boards.

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    "If you want more fiber, eat the package.· Not enough?· Eat the manual."········
    ···················· Tropical regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan
  • nick bernardnick bernard Posts: 329
    edited 2006-11-27 19:23
    here's my *.sch and *.pcb cropped into a *.jpg

    i'm using 2.2k pullups

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    jank.JPG
    963 x 797 - 159K
    jank.JPG 158.6K
  • nick bernardnick bernard Posts: 329
    edited 2006-11-28 14:54
    woo woo,
    i found the problem. it was hardware related.
    i assembled another pcb with a hotplate reflow & solder paste and it works fine
    tyvm guys!

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    engineer, fireman, bowler, father, WoW addict [noparse];)[/noparse]
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