![background image](http://html.mh-extra.com/html/texas-instruments/msp53c691/msp53c691_user-manual_1097147050.webp)
Description of the Command Codes
3-28
another phrase after receiving the four nibbles (0, 0, 5, and 4) from the
MSP53C691. After that, the master only needs to respond and send FM
data when requested by the slave. If there is no more FM data to send, the
master sends valid or dummy commands (0x00) in response to the
lowering of INRDY.
27) After finishing sending the last nibble of FM data in the FM file, the master
can send dummy data (0xFF) to the slave in response to each consecutive
lowering of INRDY by the MSP53C691 until the FM finishes playing.
28) When the MSP53C691 finishes playing FM, it pulls OUTRDY low.
29) The master must read the data from the bus. Note that only the lower four
bits of the bus are valid data. The OUTRDY goes low three more times af-
ter that, sending a total of four nibbles (0, 0, 5, and 3) if the playing of FM
was successful.
Note:
If the FM is finished while the MSP53C691 is still speaking a phrase in MELP/
CELP, then the MSP53C691 sends 0, 0, 5, and 3 to let the master know that
the playing of FM has ended and continues to pull INRDY low to receive the
MELP/CELP speech data. The master must continue to send the CELP/
MELP data to the MSP53C691.
30) When both the FM and the CELP/MELP files have ended, the
MSP53C691 sends four more nibbles (0, 0, 5, and 5) to the master to
indicate that the playing for mixed mode has ended.
31) After that INRDY goes low, indicating that the MSP53C691 is ready for a
new command.
Note:
The master cannot restart a new FM file after an FM file has finished playing
while a speech file is in progress. However, the master can issue a new com-
mand to speak in four-bit mixed mode after both the FM and the CELP/MELP
file has ended.
While playing FM and CELP in mixed mode, only a new CELP file can be re-
started. In a similar way, only a new MELP file can be restarted while playing
FM and MELP. A new MELP file cannot be restarted while playing FM and
CELP. A new CELP file cannot be restarted while playing FM and MELP.
3.5.4.6
Playing Sinewave in Test Mode
If the test mode to play a pure sine wave is selected, the MSP53C691 plays
a pure sine wave tone. The tone comes over the DAC pins of the MSP53C691.
If a 32-
Ω
speaker is directly connected to the output, a pure sine wave tone
can be heard. The following is a typical sequence of events for the test mode:
1) The MSP53C691 pulls INRDY low and waits for a command from the
master.
2) The master sends 0x4 as command header on the data bus. Note that by
writing 0x04 to the data bus ensures that the DATA4 line is also low, indi-
cating that the value on the data lines DATA0–DATA3 is a command.
Summary of Contents for MSP53C691
Page 1: ...MSP53C691 Speech Synthesizer December 2000 MSDS Speech User s Guide SPSU020 ...
Page 22: ...2 10 ...
Page 96: ...C 6 ...