ISD4002 SERIES
Publication Release Date: September 2003
- 17 - Revision 1
Message Cueing
Message cueing (MC) allows the user to skip through messages, without knowing the actual physical
location of the messages. It will stop when an EOM marker is reached. Then, the internal address
counter will point to the next message. Also, it will enter into OVF condition when it reaches the end of
memory. In this mode, the messages are skipped 1,600 times faster than the normal playback
mode.
Power-Up Sequence
The ISD4002 will be ready for an operation after power-up command is sent and followed by the T
PUD
timing (25 ms for 8 KHz sampling rate). Refer to the AC timing table for other T
PUD
values with respect
to different sampling rates.
The following sequences are recommended for optimized Record and Playback operations.
Record Mode
1. Send POWERUP command.
2. Wait T
PUD
(power-up delay).
3. Send POWERUP command.
4. Wait 2 x T
PUD
(power-up delay).
5. a). Send SETREC command with address xx, or
b). Send REC command (recording from current location).
6. Send STOP command to stop recording.
7. Wait T
STOP/PAUSE.
For 5.a), the device will start recording at address xx and will generate an interrupt when an overflow
(end of memory array) is reached, if no STOP command is sent before that. Then, it will automatic
stop recording operation.
Playback Mode
1. Send POWERUP command
2. Wait T
PUD
(power-up delay)
3. a). Send SETPLAY command with address xx, or
b). Send PLAY command (playback from current location).
4. a). Send STOP command to halt the playback operation, or
b). Wait for playback operation to stop automatically, when an EOM or OVF is reached.
5. Wait T
STOP/PAUSE.
For 3.a), the device will start playback at address xx and it will generate an interrupt when an EOM or
OVF is reached. It will then stop playback operation.
