PRELIMINARY ISD1700 SERIES
Publication Release Date: Nov 6, 2008
- 21 -
Revision 1.31
•
If messages are present, the record pointer points to the next available memory row following
the last message and the playback pointer points to the beginning of the last recorded
message.
The playback pointer is affected either by the
FWD
or
REC
operation. The record pointer is
updated to the next available memory row after each
REC
operation.
8.2.1
Record Operation
The
REC
controls recording operation. Once setting this pin Low, the device starts recording
from the next available row in memory and continues recording until either the
REC
returns
to High or the memory is full. The source of recording is from either MIC+/- or AnaIn, whereas
the active analog configuration path is determined by the desired operation and the state of
the
FT
. The
REC
is debounced internally. After recording, the record pointer will move to
the next available row from the last recorded message and the playback pointer will position
at the beginning of the newly recorded message.
However, it is important to perform an Erase operation on the desired location before any
recording proceeds. In addition, the power supply must remain On during the entire recording
process. If power is interrupted during recording process, the circular memory architecture will
be destroyed. As a result, next time when a push button operation starts, the LED will blink
seven times, which indicates that something unusual has occurred, and the device will fail to
perform the requested operation. Under such scenario, the only way to recover the chip to a
proper state is to perform a Global Erase operation.
Message recording indicators
:
The built-in message management technique associates special Sound Effects, SE1 and
SE2, within the recording process.
a) When
REC
goes Low:
•
If SE1 is not programmed, then the LED turns On immediately to indicate that a
recording is in progress.
•
If SE1 is programmed, device plays SE1 and blinks LED simultaneously. Then LED
turns On to show recording is in process. The LED blinking period of SE1 is
determined by the recorded duration of SE1 (T
SE1
). (Refer to AC timing parameter
and timing diagrams for details.)
b) When
REC
goes High or when the memory is full:
•
If SE2 is not programmed, then the LED turns Off immediately to indicate that the
recording halts.
•
If SE2 is programmed, device plays SE2 and flashes LED simultaneously. Then
LED turns Off to show recording stops. The LED blinking period of SE2 is
determined by the recorded duration of SE2 (T
SE2
).
Triggering of
REC
during a play, erase or forward operation is an illegal operation and will be
ignored.
8.2.2
Playback Operation
Two playback modes can be executed by
PLAY
, which is internally debounced.
