Setting the Receive Sign-Extension and Justification Mode
Receiver Configuration
7-20
SPRU592E
7.14 Setting the Receive Sign-Extension and Justification Mode
received by the McBSP is sign extended and how it is justified.
Figure 7
−
14. Register Bits Used to Set the Receive Sign-Extension and Justification Mode
SPCR1
15
14
13 12
0
RJUST
R/W-00
Legend:
R = Read; W = Write; -
n
= Value after reset
Table 7
−
15. Register Bits Used to Set the Receive Sign-Extension and Justification Mode
Register
Bit
Name
Function
SPCR1
14-13 RJUST
Receive Sign-Extension and Justification Mode
RJUST = 00
Right justify data and zero fill MSBs in DRR[1,2]
RJUST = 01
Right justify data and sign extend it into the MSBs in
DRR[1,2]
RJUST = 10
Left justify data and zero fill LSBs in DRR[1,2]
RJUST = 11
Reserved
7.14.1 About the Sign Extension and the Justification
RJUST in SPCR1 selects whether data in RBR[1,2] is right- or left-justified
(with respect to the MSB) in DRR[1,2] and how unused bits in DRR[1,2] are
filled—with zeros or with sign bits.
17 show the effects of various RJUST values. The
first table shows the effect on an example 12-bit receive-data value 0xABC.
The second table shows the effect on an example 20-bit receive-data value
0xABCDE.
Table 7
−
16. Example: Use of RJUST Field With 12-Bit Data Value 0xABC
RJUST
Justification
Extension
Value in
DRR2
Value in
DRR1
00b
Right
Zero fill MSBs
0000h
0ABCh
01b
Right
Sign extend data into
MSBs
FFFFh
FABCh
10b
Left
Zero fill LSBs
0000h
ABC0h
11b
Reserved
Reserved
Reserved
Reserved
Summary of Contents for TMS320VC5509
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Page 43: ...McBSP Operation 2 20 SPRU592E This page is intentionally left blank ...
Page 105: ...SPI Operation Using the Clock Stop Mode 6 16 SPRU592E This page is intentionally left blank ...
Page 187: ...Transmitter Configuration 8 40 SPRU592E This page is intentionally left blank ...
Page 191: ...General Purpose I O on the McBSP Pins 9 4 SPRU592E This page is intentionally left blank ...
Page 201: ...Emulation Power and Reset Considerations 10 10 SPRU592E ...
Page 207: ...Data Packing Examples 11 6 SPRU592E This page is intentionally left blank ...
Page 273: ...McBSP Register Worksheet 13 14 SPRU592E This page is intentionally left blank ...