Texas Instruments MSP53C691, User Manual, Page: 29 / 112

Command Codes
3-7
MSP53C691 Software Description
Table 3–1. Command Codes (Continued)
Adjust the Volume
6 1 none none Level 1 (lowest volume)
6 2 none none Level 2
6 3 none none Level 3
6 4 none none Level 4
6 5 none none Level 5
6 6 none none Level 6 (highest volume)
Command
Header
Parameters
Level 1 Level 2
Return
Values
Description
Return Status of Data Buffers
7 1 None N
1
N
2
N
3
N
4
Returns the number of bytes required to fill up the
CELP/MELP buffer
7 2 None N
1
N
2
N
3
N
4
Returns the number of bytes required to fill up the FM
buffer
Initiate Sleep Mode
8 1 None None Light sleep (see Table 2–3 of SPSU014)
8 2 None None Mid sleep (see Table 2–3 of SPSU014)
8 3 None None Deep sleep (see Table 2–3 of SPSU014)
Wake-up from sleep mode can be performed by putting
dummy data in the bus and pulsing STROBE
Receive FM Data
9 N None None Receive FM data
N = number of FM bytes the master is going to send
Perform Speed/Pitch Shift
A 0 N
1
N
2
N
3
N
4
None Slow down MELP
A 1 N
1
N
2
N
3
N
4
None Speed up MELP
A 2 N
1
N
2
N
3
N
4
None Pitch shift in MELP
A 3 None None Reserved (TI test code)
Oscillator Control
B 1 None None Crystal mode
B 2 None None Resistor trim mode
Note: Each nibble is sent to the master with DATA4 bit set to 0, indicating that it is a command.
N—Represents one nibble.
N1N2N3N4—Represents four nibbles, with N1 being the first nibble sent and N4 being the 4th nibble sent.
The numbers in the box represent the actual value of the nibble sent to the MSP53C691.