Texas Instruments TMS320C2XX - Manual (Page 394)

Receiver Operation
9-26
3) The remaining bits in the word are then shifted into the RSR, one by one
at the falling edge of each consecutive clock cycle.
4) After all bits have been received, if the FIFO buffer is not full, the contents
of the RSR are copied to the receive FIFO buffer. If the receive FIFO buffer
does become full, an interrupt (RINT) is sent to the CPU, and if overflow
has occurred, the overflow (OVF) bit of the SSPCR is set.
5) The process then repeats itself, except that there are no additional frame
sync pulses.
If a frame sync pulse occurs during reception, then reception is restarted and
the bits in the current word that were shifted into the RSR before the pulse are
lost.
If the FIFO buffer becomes full, no new words will be received into the buffer
until at least one word has been read from the buffer (through the SDTR). Once
the continuous reception is started, the port will always be reading in the values
on the DR pin. To stop continuous mode reception, reset the port.
Figure 9–9. Continuous Mode Reception
CLKR
FSR
DR
RINT
Word loaded
to buffer
from RSR
A15 A14 A13 A12 A11 A10 ... A0
LSB MSB
B15 B14 B13 B12
Word loaded
to buffer
from RSR
B11
MSB