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Single-Chip Voice Recording & Playback Device for Multiple 40- to 60-Second Messages

message segment. The entire previous message is then

overwritten by the new message, regardless of the duration

of the new message. Transitions on any other message trig-

ger pin or the /RE pin during the record operation are ignored

until after the device enters standby mode.

Functional Description of Playback in Random Access

Mode

On power up, the device is ready to record or playback, in

any of the enabled message segments. To playback, /CE

must be set low to enable the device and /RE must be set

high to disable recording & enable playback. You initiate play-

back by applying a high to low edge on the message trigger

pin that representing the message segment you intend to

playback. Playback will continue until the end of the message

is reached. If a high to low edge occurs on the same mes-

sage trigger pin during playback, playback of the current

message stops immediately.

If a different message trigger pin pulses during playback,

playback of the current message stops immediately (indi-

cated by one beep) and playback of the new message seg-

ment begins. A delay equal to 8,400 cycles of the sample

clock will be encountered before the device starts playing the

new message.

If a message trigger pin is held low, the selected message is

played back repeatedly as long as the trigger pin stays low. A

period of silence, of a duration equal to 8,400 cycles of the

sampling clock, will be inserted during looping as an indicator

to the user of the transition between the end and the begin-

ning of the message.

Tape Mode

Tape mode manages messages sequentially much like tradi-

tional cassette tape recorders. Within tape mode two options

exist, auto rewind and normal. Auto rewind mode configures

the device to automatically rewind to the beginning of the

message immediately following recording or playback of the

message. In tape mode, using either option, messages must

be recorded or played back sequentially, much like a tradi-

tional cassette tape recorder.

Function Description Recording in Tape Mode using the

On power up, the device is ready to record or play back, start-

ing at the first address in the memory array. To record, /CE

must be set low to enable the device and /RE must be set low

to enable recording. A falling edge of the /M1_Message pin

initiates voice recording (indicated by one beep). A subse-

quent rising edge of the /M1_Message pin during recording

stops the recording (also indicated by one beep). If the

/M1_Message pin is held low beyond the end of the available

memory, recording will stop automatically (indicated by two

beeps). The device will then assert a logic low on the

/M7_END pin for a duration equal to 1600 cycles of the sam-

ple clock, regardless of the state of the /M1_Message pin.

The device returns to standby mode when the /M1_Message

pin goes high again.

After recording is finished the device will automatically rewind

to the beginning of the most recently recorded message and

wait for the next user input. The auto rewind function is con-

venient because it allows the user to immediately playback

and review the message without the need to rewind. How-

ever, caution must be practiced because a subsequent

record operation will overwrite the last recorded message

unless the user remembers to pulse the /M2_Next pin in

order to increment the device past the current message.

A subsequent falling edge on the /M1_Message pin starts a

new record operation, overwriting the previously existing

message. You can preserve the previously recorded mes-

sage by using the /M2_Next input to initiate recording in the

next available message segment. To perform this function,

the /M2_Next pin must be pulled low for at least 400 cycles of

the sample clock.

The auto rewind mode allows the user to record over the pre-

vious message simply by initiating a record sequence without

first toggling the /M2_Next pin. To record over any other mes-

sage however requires a different sequence. You must pulse

the /CE pin low once to rewind the device to the beginning of

the voice memory.The /M2_Next pin must then be pulsed low

for the specified number of times to move to the start of the

message you wish to overwrite. Upon arriving at the desired

message a record sequence can be initiated to overwrite the

previously recorded material. After you overwrite the mes-

sage it becomes the last available message and all previ-

ously recorded messages following this message become

inaccessible. If during a record operation all the available

memory is used the device will stop recording automatically,

(double beep) and set the /M7_END pin low for a duration

equal to 1600 cycles of the sample clock. Playback can be

initiated on this last message, but pulsing the /M2_Next pin

will put the device into an “overflow state”.

Once the device enters an overflow state any subsequent

pulsing of /M1_Message or /M2_Next will only result in a dou-

ble beep and setting of the /M7_END pin low for a duration

equal to 400 cycles of the sample clock. To proceed from this

state the user must rewind the device to the beginning of the

memory array. This can be accomplished by toggling the /CE

pin low or cycling power. All inputs, except the /CE pin, are

ignored during recording.

APR9600

APLUS

Normal Option