Hello Chaps,
                   I recently examined the rather impressive source code
wrote by Dan Mullally for the control of an ISD 3300 speech record/playback
IC, but being a total newcommer to microcontrollers I am rather confused
about the 3 Volt to 5 Volt interface requirements. Do both the ISD and the
PIC IC's operate from a 3 volt supply in this project or is there some level
shifting electronics required in-between ??. - perhaps this is the pull-up's
which Dan mentions, or are these pull-up's merely required in order to
satisfy the input requirements of the ISD3300 chip ??.
         Also does understand the operation of the message queueing feature
of the ISD3300 ?, my requirements are to record and playback several short
messages, (10-15 seconds) without having to determine the start and stop
address of each message. I have read most of the datasheets for the device
but I am still confused as to whether the INT pin of the ISD3300 must be
connected to the PIC for EOM detection, or whether the message cueueing
feature can be enabled in order to automatically skip to the next message in
the queue. - The ideal requirement for me would be to either pulse one of the
PIC's I/O lines once for message 1, twice for message 2 etc. or to send SPI
data to the ISD3300 requesting message 1, message 2 etc. The problem is that
I do not fully understand the operation and configuration of the message
queueing feature, - and what's all this about playback at 800 times the
normal speed but with muted audio output ??
      If anyone could possibly clarify any the above I would be very
greatful.

    Many Thanks Lee Hewitt (Manchestar ENGLAND)