Since it seems that several people on this list have used the
ISD4003 sound recorder chips, I thought I'd ask a few questions here.  I
believe I'm sending correct serial data to the chip, but it doesn't seem
to be doing much.

        I am sending 16 bit commands, least significant bit first.  The
sequence is

        1.  set -SS low
        2.  set or clear data bit as appropriate
        3.  set clock high
        4.  set clock low
        5.  set or clear data bit for next bit as appropriate, etc.
        6.  After all 16 bits sent, set -SS high.

        This is currently running on a Picmaster 16c74 emulator (to watch
the lines, the programming a 16c74 to actually drive the ISD chip at 3V),
though I'll move it to a 16c61 for production.  It's running with a 30
KHz clock, so I believe all timing stuff is being met.  I've watched the
lines change with the logic analyzer in the PicMaster, and stuff appears
proper.

        I'm currently sending the following commands:

        0x2000  power up
                wait at least 25 ms
        0xe004  set play pointer to address 0004
        0xf004  play

        I note on page 3 of the datasheet that the AUDOUT pin is "always
at 1.2 volts when the device is powered up."  I'm finding that it stays
at 0V, which indicates to me the above power up command is not being
interpreted correctly.
        Anyone see what's wrong?  I AM sending the bits in the right
order, right?


Thanks!

Harold



Harold Hallikainen
harold@hallikainen.com
Hallikainen & Friends, Inc.
See the FCC Rules at http://hallikainen.com/FccRules and comments filed
in LPFM proceeding at http://hallikainen.com/lpfm

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