
D6385A
A
System Functions
All of the speech processing tasks are done by the DSP Speech Subsystem. This allows the use of a very low cost
microcontroller to be used for basic control of the system. The Host need only send high level commands to perform
functions such as Record Message or Delete Message and the operation will be performed by the DSP subsystem which
will report the status of the operation to the Host. All memory interface and management will be taken care of by the
DSP requiring the Host to only handle high level system functions. A summary of the functions performed by the DSP
Speech Subsystem and Host Controller are shown in Figure 3, below.
n
Speech Recording
n
Speech Playback
n
Memory / Message Management
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DTMF and Tone Genertion
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DTMF Detection
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Call Process Detection
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Time / Date Stamping
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Voice Prompts
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Phone Number Storage
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SpeakerPhone Functions
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Slave CODEC Operation
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Control the System
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Read Buttons
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Control Displays / Switches
Host Controller
DSP Speech Subsystem
Figure 3. System Functions
Simple Hardware Interface
The hardware interface between the D6385A and the Host Controller is a simple one requiring only an 8 bit parallel
port and 4 handshake lines. The Host writes high level Commands to the D6385A and the D6385A will respond with
Status information. Once a Command is issued the D6385A will use the ACK pin to indicate that the Status is
available to be read. The hardware interface between the D6385A and Host is shown in Figure 4 below.
HSTD0-7
HSTR
HSTW
HI/LO
ACK
Port 0
RD
WR
HI/LO
INT
8051
D6385A-11
8
Figure 4. D6385A / Host Interface