vendredi 15 juillet 2011

Updates .. ! .. not that much ..

After a while (7 months) I started again this project.
I tried to remove all transistor and put in place the 74125 ICs (don't have 74126) but getting strange problems.

I get a kind of 1.4 V DC offset on the input of the buffers (strange), which interfer with the CTL1 and CTL8 input (to the arduino). Just thinking of bypass the buffer for the inputs or get new 74hc126 ICs.
The ones i'm using are very very old (15 year old or more) and when i look at the datasheet the spec of the IC are very "shitty" for example with a typical Power of 4.5V the high output typical voltage 3.4 V.

I also updated my Open logic Sniffer but it still difficult to understand exactly the signals on the S&S.
To really understand the Bus data, need to find a procedure to force a speak without adding something on the S&S screen. (BTW i'm currently using a Speak and Read because i've got strange results with the Speak and spell due to to many experimentations)

next step : order new 74HC126 and test bypass buffer for input before i receive the package.

3 commentaires:

  1. HI there!
    I'm very interested by this project.

    Maybe you have it:
    Original paper from L. Dighera can be found here

    an very interesting source of information:

    and the TMS5220 Speech Chip datasheet from TI:
    (thanks to

    and also some way to explore:

  2. thanks for you interest,
    I've already read the paper from L. Dighera (all my work is based on this one)
    I've already seen the you tube video, but actually i don't planned to create my own sample yet.

    Many thanks for the datasheet (i've one but not complete) and the other link seems to be very interesting, i will investigate theses.

    Will keep you informed ..
    By the way, i've received my 74hc126 but didn't get the time to use them yet ..

  3. Any chance you can release the arduino code source? I'd love to give it a shot!