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D6571E

EASYTAD™ Chip for an All- Digital Telephone Answering Machine with Flash Memory Interface

Unspecified 

D6571E Data Sheet

sending the Idle mode status word. The D6571E

assigns the next available message number to a newly

recorded message. The first message will be assigned

the number “0”, the second message will be assigned

the number “1”, and so on, up to “127”.

Record mode can be terminated by sending a Record

command with non-zero “Tail Cut” factor (TCF). The

D6571E stops recording and automatically deletes the

last n*TCF seconds from memory. The value of the TCF

is 0.160 seconds for 8000 Hz sampling rate and 0.178

seconds for 7200 Hz sampling rate. The D6571E then

returns to Idle mode. For PCM recording the value of

the TCF is 0.240 seconds and 0.266 seconds for 8 KHz

and 7.2 KHz sampling rate respectively.

Host can pause recording by sending Record command

with REC MODE = 10. The D6571E will stay in Record

mode, monitor line but won’t store data into flash. The

Host can send Record command with REC MODE = 00

to continue recording or terminate recording by Idle or

Tail Cut command.

If the Flash memory has become full, the Memory Full

bit (bit 7) in the status word is set. The D6571E stops

recording, remains in Record mode, and continues to

perform line monitoring.

During Record mode, the HOST can instruct the D6571E

to generate a tone from the predefined tone table. The

HOST should issue a Record command with the “T” bit

(bit 9) set to “1”, Tone Gain (bits 8-5) and “Tone Index”

(bits 4-0). Tone generation will end if “Tone Index” is

“00000” along with the “T” bit set to “1”. For more

details about tone generation, see Tone Generation

command.

In Record mode, the input signal is “Looped Back” and

transmitted through the output of the CODEC. This can

be used for call screening or other purposes. If the

“Loop Back” is not necessary, the HOST can disable

this function by setting the “LB DIS” bit (bit 5) in the

first record command to “1”. The “LB DIS” bit should

usually be set to “1” if the tone generation function

during Record is used.

Host can suspend recording (Record command with

REC MODE = 01). The D6571E will terminate recording

and go to Idle mode. The Host can instruct the D6571E

to perform another operation (other than Record), for

example, CID, Tone Generation, etc. Note that message

playback, voice prompt playback, and new message

recording is not available during record suspend.

Then Host may instruct the D6571E to resume recording

of the message that has been suspended. Alternatively

the Host can close the suspended message and then

start new message recording.

The Host may instruct the D6571E to change

compression rate, enable/disable Gap Coding and

Loopback (REC MODE = 11 and TONE GEN = 1). New

mode will be set in the bits NEW BIT RATE (bits 8 - 6),

LB DIS (bit 5), and GAP (bit 4).

Host can also instruct the D6571E to report current

offset in the message being recorded (REC MODE = 11

and TON GEN = 0).

A message will not be stored in the Flash memory if the

actual message length is less than 1 second. After

performing the tail cut function, or if the message length

is less than 1 second, the Garbage Collection

Recommended bit will be set (1) in the status of the

Read Memory Status command.

In case of “cold start” the Record will not be activated,

the D6571E remains in Idle mode and returns Idle status.

Playback

In playback mode, the D6571E performs message

playback and line monitoring. In the first playback

command, the HOST instructs the D6571E which

message to play, and at what FLEXISPEECH speed.

The message number is defined in bits 0-6 and can be

from 0 to 127. The FLEXISPEECH speed is defined in

bits 7-9. To play a message at normal speed, the FLEXI

speed should be “000”. Other playback speeds, from 0.5

to 2.0 (50% - 200%) of the normal speed can be selected

according to the following table:

Bit 9

0

0

0

0

1

1

1

1

FLEXI SPEED

Bit 8

0

0

1

1

0

0

1

1

Bit 7

0

1

0

1

0

1

0

1

SPEED OF

PLAYBACK

1.0

0.5

0.7

1.0

1.3

1.5

1.75

2.0

The second playback command instructs the D6571E to

play back the message from the predefined offset

location. This offset information is defined in units of

DS6571E.2

DSP GROUP, INC., 3120 SCOTT BOULEVARD

14

SANTA CLARA, CA 95054 PH: 408 986-4300 FAX: 408 986-4490

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