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Command Codes
3-5
MSP53C691 Software Description
Returned Values
Description
0x0055
Returned when the MSP53C691 successfully plays a speech file. In mix mode,
0x0055 is returned when the MSP53C691 has finished playing both the FM and
the speech file.
0x0054
Returned in mix mode when the MSP53C691 has successfully finished playing
a speech file and is waiting to start a new file or for the FM to finish playing.
0x0053
Returned in mix mode when the MSP53C691 has successfully finished playing
an FM file and is waiting for the speech file to finish playing.
0x9999
Returned when an error is encountered. This error is returned when either:
•
An invalid command header or and invalid level 1 or level 2 parameter is
issued by the master.
•
An invalid port address to be written to or to be read from is specified.
•
An invalid file format is encountered while playing multiple files In mix mode.
0x1234
Returned when there is an error recognizing the header byte in the speech file
or the stack is overflowed
0x0N23
Returned (in mix mode or while speaking FM only) when the FM buffer becomes
nearly empty and FM data is needed to fill up the FM buffer. N denotes the num-
ber of FM bytes needed to fill up the FM buffer.
CAUTION
The MSP53C691 waits until all of the four nibbles have been sent to the
microcontroller. If the microcontroller delays in reading the data from the
MSP53C691, the speech operation can be interrupted. Therefore, the
microcontroller must read the data as soon as the OUTRDY goes low.
3.4
Command Codes
The valid command codes are described in Table 3–1 and paragraph 3.5.
Command codes include the command header (one nibble), level 1
parameters (one or two nibbles), and, sometimes, level 2 (four nibbles)
parameters. As shown in Table 3–1, there are occasions when values are
returned to the slave as a result of the command that is initiated. These return
values are always four nibbles in size and are sent over the DATA0–DATA3
data lines.
In four-bit mode, the commands (command header and level 1 and level 2
parameters) are sent to the MSP53C691 four bits (a nibble) at a time with
DATA4 set to 0 for every transmitted nibble. In four-bit mode, commands can
be sent while speaking a phrase, but in eight-bit mode commands can only be
sent between speaking phrases. After receiving the command to speak in 8-bit
mode, the slave expects speech data in 8–bits. No other command can be sent
to the slave during speaking. The slave goes to the 4-bit mode to receive
Summary of Contents for MSP53C691
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