TrueSpeech® Co-Processor
PRELIMINARY/CONFIDENTIAL
Version: 1.18
Host-To-Host Compression Data Transfer [1] and [2]
Host starts compression process [1] by issuing compression C1 command, and waits for Status Ready in the
Hardware Status Register to be asserted.
CT8022 acknowledges start of compression with compression S1 response.
If the READY flag is set in status response S1:
Host transfers uncompressed data by writing the (240) uncompressed data words to the Software Control register and
waiting for STATUS READY to be set after each word written. Each time STATUS READY is set, the Host must
read the Software Status Register in order to clear STATUS READY. The actual value read from the Software
Status Register is the same as (echo of) the last data word written.
The compression C1 and S1 status response - READY flag are used to control subsequent uncompressed speech data
transfers[1] to the CT8022.
Once compression has been started, the Host transfers compressed data from the CT8022 [2] using the normal
record data transfer protocol (TFR Mode = 00 or 11).
The record protocol used to transfer compressed speech data frames from the CT8022 also supports the Buffer
Monitoring, Frame Create, Frame Delete, and Record Stop commands.
Host-to-Host compression can be terminated either using the Record Stop command or the Idle command. One of
these commands should be issued during the command-status sequence in place of the compression C1 command.
Compression READY Polling
Instead of using the compression S1 status READY response to determine if the CT8022 is ready to accept more
uncompressed speech data, the Host can poll the READY state using the following command:
command:
status:
5119H
0000H
0001H
if CT8022 is ready to accept more uncompressed data.
if CT8022 is not ready to accept more uncompressed data.
This command is only valid if compression mode is active.
The advantage this command offers over simple use of the compression C1-S1 command-status is that it allows the
Host to query the READY state without immediately committing to performing the data transfer. With the
compression C1-S1 command-status, if the READY bit in the S1 status response is set, the Host must immediately
transfer data.
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DSP GROUP, INC., 3120 SCOTT BOULEVARD CT8022A11AQC FW Revision 0118
SANTA CLARA, CA 95054 PH: 408 986 – 4300 FAX: 408 986 – 4490
All specifications are subject to change without prior notice.
ETC [ ETC ]
