Texas Instruments TMS320C6201 Reference Manual page 367

11.3.8 Receive Data Justification and Sign Extension: RJUST
Table 11–12. Effect of RJUST Values With 12-Bit Example Data ABCh
11.3.9 32-Bit Bit Reversal: (R/X)WDREVRS
RJUST in the SPCR selects whether data in the RBR is right- or left-justified
(with respect to the MSB) in the DRR. If right justification is selected, RJUST
further selects whether the data is sign-extended or zero-filled. Table 11–12
summarizes the effect that various values of RJUST have on an example
12-bit receive data value ABCh.
RJUST value Justification
00 Right
01 Right
10 Left
11 Reserved
The 32-bit bit reversal feature is only available for the 'C6211/C6711 device.
Normally all transfers are sent and received with the MSB first. However, if you
set the RWDREVRS field to 1 in the RCR, or the XWDREVRS field to 1 in the
XCR, the bit ordering of the 32-bit elements is reversed (LSB first) before being
received by or sent from the serial port. The (R/X)WDLEN(1/2) fields in the
(R/X)CR should be set to 101b to indicate 32-bit elements. Otherwise the
operation is undefined.
Data Transmission and Reception
Extension
Zero-fill MSBs
Sign-extend MSBs
Zero-fill LSBs
Reserved
Multichannel Buffered Serial Ports
Value in DRR
0000 0ABCh
FFFF FABCh
ABC0 0000h
Reserved
11-49