YSS920B
Note 3) Various status signal output pins
By setting the IOSEL and the OPSEL, the following status signals will be output from each pin:
IOPORT16-----
OVF
IOPORT17-----
END
IOPORT18-----
SDBCKO (64fs clock)
IOPORT19-----
SDWCKO (fs clock)
OVF
If overflow occurs in the operation result of the DSP, OVF is set to H.
The H interval is from the occurrence of the overflow to the output start of the next PCM
sample from the SDO interface. When the next PCM sample output starts, OVF is reset to L.
This pin is used for DSP programming and debugging.
END is set to H when the DSP program counter is active. It is set to L when all processes
have been finished and the program counter stops. When the program is operating correctly,
the pin is always set to L once per sample. If it is not, this indicates that the program has not
finished correctly to the end. This pin is used for DSP programming and debugging.
END
SDBCKO
This pin outputs 64fs clock synchronized to the SDO output signal. This clock can be used as
a 64fs clock for the devices in subsequent stages. The polarity of the SDBCKO clock can be
selected by setting BCKOP of the SDO register.
SDWCKO
This pin outputs fs clock synchronized to the SDO output signal. This clock can be used as an
fs clock for the devices in subsequent stages. The polarity of the SDWCKO clock can be
selected by setting WCKOP of the SDO register.
Each pin of IOPORT 19-0 is pulled up with 80-kΩ (Typ) resistors. The structure of the LSI is shown below:
Structure of the LSI
IPORT
OPSEL
IOPORT
OPORT
Zero detection
or status signal
IOSEL
Note 4) When the pins are set to input mode, set a branch condition directly to each pin.
When the pins are set to output mode, IOPORT output can be used as the branch condition.
9
YAMAHA [ YAMAHA CORPORATION ]
