TPU 3035, TPU 3040
PRELIMINARY DATA SHEET
4.14. Subpage Manager
subpage
pointer
Page Table
Any page in cycle can have a number of subpages, iden-
tifiedbysubcode. Innormalmodethesubpagemanager
will acquire only one subpage of every requested page.
This subpage can be any if subcode FFFF is requested
oritwillbeselectedaccordingtotherequestedsubcode.
page 100
subcode 0003
page pointer
AfteraPAGE_REQUESTcommandwithsubcodeF0xx,
the subpage manager will acquire all subpages of the
requested page. The subpages will be chained in the
same order as they are transmitted, i.e. every new sub-
code will be added at the end of chain. The page table
entry points to the subpage which was transmitted first
after the page request. The READ_PAGE_INFO com-
mand will reply the page table pointer and the actual
number of subpages in chain.
subpage
pointer
page 100
subcode 0001
AfteraPAGE_REQUESTcommandwithsubcodeF1xx,
thesubpagemanagerwillacquireallsubpagesofthere-
quested page but will allocate only a limited amount of
memory to store these subpages. The parameter “page
subcode low” will define the length (in number of sub-
pages) of a ring buffer in page memory which will hold
the recently received subpages. In this case, the
READ_PAGE_INFO command will return an index
pointing to the most recently updated subpage in chain,
together with the subcode of this page.
0000
page 100
subcode 0002
Fig. 4–12: Subpage Organisation
The DISPLAY_PAGE_REQUEST command searches
and displays a page according to the requested display
subcode. The search starts from page table and contin-
ues through the subpage chain if there is any. A rolling
header will be displayed if the requested subpage can-
not be found in memory.
ArequesteddisplaysubcodeFFFF(don’tcaresubcode)
will only search and display the first subpage in chain,
thus there is no rolling subpage anymore. A DIS-
PLAY_PAGE_REQUEST command with subcode F0xx
(follow subcode) will search and display the last re-
ceived subpage in chain, thus it is possible to request all
subpages in background while still showing rolling sub-
pages in display.
48
MICRONAS INTERMETALL
MICRONAS [ MICRONAS ]
