Description of the Command Codes
3-33
MSP53C691 Software Description
DATA LINES
DATA4
DATA3
DATA2
DATA1
DATA0
0
X
X
X
X
4) After receiving the level 1 command, the MSP53C691 pulls INRDY low
and then goes to the requested level of sleep.
Note:
When the master is ready to wake up the MSP53C691, it must send a dummy
byte to the MSP53C691 to respond to the INRDY low.
The wakeup time from light sleep is the lowest. The MSP53C691 takes more
time to wake up from mid and deep sleep because ramp-up and stabilization
of the clock is required in mid and deep sleep.
The device draws less than 10
µ
A of current In deep sleep.
3.5.9
Command Header 9—Receive FM Data
The command header 9 is used in mixed mode to send the requested amount
of FM data to the MSP53C691. For detailed description of the command, see
the
Playing Mixed Mode in Four-Bit Mode section.
3.5.10 Command Header A—Perform Speed Shift or Pitch Shift
This command changes the speed or the pitch of a file being played in MELP.
The speed or pitch shift gives a very interesting flavor to the audio quality of
MELP. See Appendix D,
Speed and Pitch Shifting in 6xx MELP. The sequence
of events to perform pitch and speed shift is as follows:
1) The MSP53C691 pulls INRDY low, requesting for command or speech
data while playing MELP.
2) The master sends the command header 0xA to indicate the pitch or speed
shift.
DATA LINES
DATA4
DATA3
DATA2
DATA1
DATA0
0
1
0
1
0
3) After receiving the command header, the MSP53C691 pulls INRDY low
again requesting a level 1 parameter from the master. The master must
send the level 1 parameter to the MSP53C691: 0 for slowing down MELP,
1 for speeding up MELP, or 2 for pitch shifting.
Summary of Contents for MSP53C691
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