Data Packing Using Frame Length and Word Length
Data Packing Examples
11-2
SPRU592E
11.1 Data Packing Using Frame Length and Word Length
The frame length and word length can be manipulated to effectively pack data.
For example, consider a situation where four 8-bit words are transferred in a
single-phase frame as shown in Figure 11
1. In this case:
-
(R/X)PHASE = 0: Single-phase frame
-
(R/X)FRLEN1 = 0000011b: 4-word frame
-
(R/X)WDLEN1 = 000b: 8-bit words
Four 8-bit data words are transferred to and from the McBSP by the CPU or
by the DMA controller. Thus, four reads from DRR1 and four writes to DXR1
are necessary for each frame.
Figure 11
−
1.Four 8-Bit Data Words Transferred To/From the McBSP
RSR1 to
RBR1 copy
RBR1 copy
RSR1 to
RSR1 to
RBR1 copy
RBR1 copy
RSR1 to
DXR1 to XSR1
copy
DXR1 to XSR1
copy
DXR1 to XSR1
copy
DXR1 to XSR1
copy
Word 1
Word 2
Word 3
Word 4
CLKR
FSR
DR
CLKX
FSX
DX
This data can also be treated as a single-phase frame consisting of one 32-bit
data word, as shown in Figure 11
2. In this case:
-
(R/X)PHASE = 0: Single-phase frame
-
(R/X)FRLEN1 = 0000000b: 1-word frame
-
(R/X)WDLEN1 = 101b: 32-bit word
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 ...
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