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Registers
1576
SPRUH82C – April 2013 – Revised September 2016
Copyright © 2013–2016, Texas Instruments Incorporated
Universal Parallel Port (uPP)
32.3.19 uPP DMA Channel Q Descriptor 0 Register (UPQD0)
The uPP DMA channel Q descriptor 0 register (UPQD0) programs the starting address of the data buffer,
or window, for DMA Channel Q. The address can be programmed by simply writing a 32-bit value to the
entire register. Note that the 3 lower bits are read-only and always equal to 0, so that data buffers must be
properly aligned in memory. The UPQD0 is shown in
and described in
Figure 32-34. uPP DMA Channel Q Descriptor 0 Register (UPQD0)
31
16
ADDRH
R/W-0
15
3
2
0
ADDRH
ADDR
R/W-0
R-0
LEGEND: R/W = Read/Write; R = Read only; -
n
= value after reset
Table 32-29. uPP DMA Channel Q Descriptor 0 Register (UPQD0) Field Descriptions
Bit
Field
Value
Description
31-3
ADDRH
0-1FFF FFFFh
Window Address MSBs. Sets the 29 most-significant bits of starting address for DMA Channel
Q window.
2-0
ADDR
0
Window Address LSBs. Forces window address to align to multiple of 8 bytes (64-bit buffer
alignment).
32.3.20 uPP DMA Channel Q Descriptor 1 Register (UPQD1)
The uPP DMA channel Q descriptor 1 register (UPQD1) programs the line count per window and byte
count per line for DMA Channel Q. 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 UPQD1 is shown in
and described in
Figure 32-35. uPP DMA Channel Q Descriptor 1 Register (UPQD1)
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 32-30. uPP DMA Channel Q Descriptor 1 Register (UPQD1) Field Descriptions
Bit
Field
Value
Description
31-16
LNCNT
1-FFFFh
Line Count. Sets the number of lines in the DMA Channel Q 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 Q 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).