Description of the Command Codes
3-24
OUTRDY again three more times, sending a total of four nibbles
altogether (back to back) in this way. The four nibbles sent to the master
are 1, 8, 2, and 3 respectively. The 1 and 8 are interpreted as 18H (24
decimal) bytes needed to fill up the FM buffer initially. The 2 and 3 are
interpreted as 23, characterizing the FM data request to the master.
Most Significant
DATA LINES
DATA3
DATA2
DATA1
DATA0
0
0
0
1
First nibble sent
1
0
0
0
Second nibble sent
0
0
1
0
Third nibble sent
Least Significant
0
0
1
1
Fourth nibble sent
8) The MSP53C691 then pulls INRDY low again to indicate that it is ready
to receive FM data.
9) The master can now start sending FM data from a file in response to each
lowering of INRDY. Note that the DATA4 line must be high while sending
FM, indicating that FM data is being sent. For instance, to send the FM
data byte 0x38 to the MSP53C691, the master must put 0x13 on the data
bus in response to the lowering of INRDY. When the MSP53C691 is ready
to receive the next nibble, the master puts 0x18 on the data bus.
Most Significant
DATA LINES
DATA4
DATA3
DATA2
DATA1
DATA0
1
X
X
X
X
First nibble sent
1
X
X
X
X
Second through X nibbles sent
Least Significant
1
X
X
X
X
Last (24X2=48th) nibble sent
Note:
It is very important to note that the master must send the exact number of FM
data bytes initially requested by the MSP53C691 while filling up the buffer.
If the master has finished sending the exact number of FM data bytes
requested by the MSP53C691 to initially fill up the buffer, and the
MSP53C691 has pulled INRDY low to request more data or command, the
master can either send a command to perform any task (volume control,
toggle I/O, etc.) or CELP/MELP data.
Содержание MSP53C691
Страница 1: ...MSP53C691 Speech Synthesizer December 2000 MSDS Speech User s Guide SPSU020 ...
Страница 22: ...2 10 ...
Страница 96: ...C 6 ...