TVP4020
Programmers Reference Manual
Programming Model
15
(minus 1) of the number of registers to update. To enable use of this
format, the P
ERMEDIA
register file has been organized so that registers
which are frequently loaded together have adjacent address tags. For
example, the 8 AreaStipplePattern registers can be loaded as follows:
AreaStipplePattern0, Count=7, Mode=1
row 0 bits
row 1 bits
...
row 7 bits
Indexed Format
P
ERMEDIA
address tags are 9 bit values. For the purposes of the Indexed
DMA Format they are organized into major groups and within each
group there are up to 16 tags. The low-order 4 bits of a tag give its offset
within the group. The high-order 5 bits give the major group number.
Appendix D Register Table, lists the individual registers with their Major
Group and Offset.
0
9
4
Major Group
Offset
8
Figure 3.2
Indexed Format
This format allows up to 16 registers within a group to be loaded while
still only specifying a single address tag description word.
address tag with Mask, Mode=2
value 1
...
value n
If the Mode of the address tag description word is set to indexed mode
then the high-order 16 bits are used as a mask to indicate which
registers within the group are to be used. The bottom 4 bits of the
address tag description word are unused. The group is specified by bits
4 to 8. Each bit in the mask is used to represent a unique tag within the
group. If a bit is set then the corresponding register will be loaded. The
number of bits set in the mask determines the number of data words that
should be following the tag description word in the DMA buffer. The data
is stored in order of increasing corresponding address tag. For example,
Содержание TVP4020 PERMEDIA 2
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