Registers
1573
SPRUH82C – April 2013 – Revised September 2016
Copyright © 2013–2016, Texas Instruments Incorporated
Universal Parallel Port (uPP)
32.3.14 uPP DMA Channel I Descriptor 1 Register (UPID1)
The uPP DMA channel I descriptor 1 register (UPID1) programs the line count per window and byte count
per line for DMA Channel I. The line count (LNCNT) may be set to any number from 1 to 65 535 (FFFFh),
but must not be cleared to 0. The byte count (BCNT) may only be set to an even number. For a simple
transfer, LNCNT may be set to 1, and BCNT may be set to N >> 1, where N is the desired byte count of
the entire DMA transfer. Note that the lower bit is read-only and is always equal 0, so that N is an even
number. The UPID1 is shown in
and described in
.
Figure 32-29. uPP DMA Channel I Descriptor 1 Register (UPID1)
31
16
LNCNT
R/W-0
15
1
0
BCNTH
BCNT
R/W-0
R-0
LEGEND: R/W = Read/Write; R = Read only; -
n
= value after reset
Table 32-24. uPP DMA Channel I Descriptor 1 Register (UPID1) Field Descriptions
Bit
Field
Value
Description
31-16
LNCNT
1-FFFFh
Line Count. Sets the number of lines in the DMA Channel I window.
0
Invalid value
15-1
BCNTH
1-7FFFh
Byte Count MSBs. Sets the 15 most-significant bits of the number of bytes per line in the DMA
Channel I window.
0
Invalid value
0
BCNT
0
Byte Count LSB. Forces the number of bytes per line to an even value (multiple of 2 bytes).
32.3.15 uPP DMA Channel I Descriptor 2 Register (UPID2)
The uPP DMA channel I descriptor 2 register (UPID2) programs the offset address between lines within
the DMA Channel I window. Note that the 3 lower bits are read-only and always equal 0, so that the line
offset address is aligned to a multiple of 8 bytes, similar to the window address in UPID0. Writing a value
of 0 to UPID2 effectively repeats the same (first) line
UPID1.LNCNT
times. The UPID2 is shown in
and described in
.
Figure 32-30. uPP DMA Channel I Descriptor 2 Register (UPID2)
31
16
Reserved
R-0
15
3
2
0
LNOFFSETH
LNOFFSET
R/W-0
R-0
LEGEND: R/W = Read/Write; R = Read only; -
n
= value after reset
Table 32-25. uPP DMA Channel I Descriptor 2 Register (UPID2) Field Descriptions
Bit
Field
Value
Description
31-16
Reserved
0
Reserved
15-3
LNOFFSETH
0-1FFFh
Line Offset Address MSBs. Sets the 13 most-significant bits of the offset address (in bytes)
between lines in the DMA Channel I window. This is a signed 2s-complement value.
2-0
LNOFFSET
0
Line Offset Address LSBs. Forces the line offset address to align to a multiple of 8 bytes (64-bit
alignment).