CT8022 Datasheet, PDF (77/194 Pages) List of Unclassifed Manufacturers – VOIP/VON G.723.1, G279AB TRUESPEECH CO-PROCESSOR

Version: 1.18
PRELIMINARY/CONFIDENTIAL
TrueSpeech® Co-Processor
The Host processor also needs to supervise the operation of the DMA controller and arrange for the re-filling of the
DMA buffer during playback (e.g. read from disk). When the DMA controller reaches the end of the DMA buffer,
the Host must re-fill the data (read from disk). The Host can arrange to receive an EOT interrupt from the DMA
controller or can periodically poll the DMA’s internal transfer count register to determine the status of the DMA.
Terminating Playback
1. Host disables DMA requests from the CT8022 by writing 0000H to the Hardware Control Register.
2. Host writes IDLE = 0000H command or STOP PLAYBACK = 5220H command to the Software Control
Register.
3. CT8022 terminates playback and clears TX Ready if set (in Hardware Status Register).
4. CT8022 writes status response to Software Status Register.
5. Host waits for STATUS READY indication in the Hardware Status Register, then reads the CT8022 response
from the Software Status Register. This clears the STATUS READY bit.
Note: After writing the Idle or Stop Playback command to terminate playback, the Host/DMA should not
attempt to access the Host Transmit Data Buffer Access Port even if the TX Ready bit is set.
Example 4: TrueSpeech 8.5 Playback using CT8005/CT8015 protocol via Software Control and Status Registers.
This example shows how to perform TrueSpeech 8.5 playback with TFR Mode = 00 using the CT8015 compatible
protocol. Data is transferred via the Software Control and Status Registers. The Host processor performs all data
transfers. The example shown uses the CT8015 Poll Sync Mode.
1. CT8022 is in IDLE or PLAYBACK state.
2. Host checks for CONTROL READY state in Hardware Status Register.
3. Host selects TrueSpeech 8.5 playback by writing the Select TrueSpeech Playback Rate command = 5230H to
the Software Control Register.
4. CT8022 responds via the Software Status Register
5. Host waits for STATUS READY indication in the Hardware Status Register, then reads the CT8022 response
from the Software Status Register. This clears the STATUS READY bit.
6. Host selects Poll Sync Mode for playback using the command 5202H.
7. CT8022 responds via the Software Status Register.
8. Host waits for STATUS READY indication in the Hardware Status Register, then reads the CT8022 response
from the Software Status Register. This clears the STATUS READY bit.
9. Host writes Playback C1 command = 2C00H (TrueSpeech 8.5) to the Software Control Register.
10. CT8022 activates playback mode and performs internal synchronizations (1-2 frame delay) .
11. CT8022 responds with Playback status S1 = 2C00H after a delay of up to 2 speech frame periods.
12. Host waits for STATUS READY indication in the Hardware Status Register, then reads the CT8022 response
from the Software Status Register. This clears the STATUS READY bit.
13. Host sends Playback C2 command = 2000H.
14. CT8022 responds with Playback S2 status = 2000H.
15. Host waits for STATUS READY indication in the Hardware Status Register, then reads the CT8022
response from the Software Status Register. This clears the STATUS READY bit.
16. Host sends Playback C3 with the number of (16 bit) words it wishes to transfer = 2010H. For
TrueSpeech 8.5 the requested transfer count should be 16 = 10H.
17. CT8022 checks number of words it is able ready to transfer.
18. CT8022 responds with Playback S3 = 2000H or 2010H. If number of words is not zero DATAFLAG/
signal is asserted to indicate the beginning of data transfer.
19. Host waits for STATUS READY indication in the Hardware Status Register, then reads the CT8022
response from the Software Status Register. This clears the STATUS READY bit.
20. If number of words to transfer is zero (S3 = 2000H), Host goes back to step 13.
21. Optional: Host waits for DATAFLAG/ signal to be asserted
22. Host writes 16-bit data word to Software Control Register
23. CT8022 responds by echoing the 16-bit data word in Software Status Register
CT8022A11AQC FW Revision 0118
DSP GROUP, INC., 3120 SCOTT BOULEVARD
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All specifications are subject to change without prior notice.