SMJ34020A_06 Datasheet, PDF (30/97 Pages) Texas Instruments – GRAPHICS SYSTEM PROCESSOR

SMJ34020A
GRAPHICS SYSTEM PROCESSOR
SGUS011D − APRIL 1991 − REVISED SEPTEMBER 2004
cycle timing examples (continued)
The local memory read-modify-write cycle (Figure 12) is used when inserting a field into memory that crosses
byte boundaries. This cycle is actually performed as a read access followed by a page-mode write cycle.
Standard Memory Write Cycle
Address Subcycle
Data Transfer
Subcycle
Page-Mode Write
Data Transfer
Subcycle
Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4† Q1 Q2 Q3 Q4 Q1
LCLCK1
LCLCK2
GI
LAD (SMJ34020A)
Address
Data Out
LAD (Memory)
Data
CAMD
RCA
Row
Column
ALTCH
RAS
CAS
WE
TR/ QE
SF
DDIN
DDOUT
LRDY
PGMD
SIZE16
BUSFLT
R0
R1
† _{See clock stretch, page 21.}
Figure 12. Local-Memory Read-Modify-Write Cycle Timing
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