9100A-017
7-9
high for two cycles (334 ns) to ensure that the data held on the
bus is valid. Using the TL/1
readword
command in the “stored”
mode will return the data read.
CRT Controller Read Cycle Vector File
GROUPS [40-21][20-13][1][2][3][4][5][7][8][6][12-9]
DISPLAY HEX,HEX,BIN
! A19 - A0 D7-D0 I I M M A R I I UNUSED
! O O E E E E O O
! R W M M N S R C
! - - W R E D L
! - - T Y K
!
! START OF READ CYCLE read addr $3D5
1 $003D5 $XX 1 1 1 1 0 0 X X XXXX
2 $003D5 $XX 0 1 1 1 0 0 X X XXXX
3 $003D5 $XX 0 1 1 1 0 0 X X XXXX
4 $003D5 $XX 0 1 1 1 0 0 X X XXXX
5 $003D5 $XX 0 1 1 1 0 0 X X XXXX
CAPTURE
6 $003D5 $XX 1 1 1 1 0 0 X X XXXX
STOP
VIDEO RAM BUS CYCLES
7.8.
Another pair of bus cycles must be determined for accessing the
video RAM. The access time of the RAM is much greater than
that of the CRT Controller and, because the RAM is shared
between the controller and bus accesses, the IORDY line is used
with the WAIT line of the module to provide synchronization.
In the Video RAM Write Cycle Vector File that follows, vector 1
sets addresses A19 through A0 and data D7 through D0. Vector
2 holds the address and data while MEMW goes low. Upon
receipt of MEMW and the correct address, IORDY goes low.
The module then waits until the UUT acknowledges the write by
returning the IORDY line high, which satisfies the WAIT
condition, and vector driving continues. Vector 3 maintains the
address and data for hold time.
Video RAM Write Cycle Vector File
GROUPS [40-21][20-13][1}[2][3][4][5J[7][8][6][12-9]
DISPLAY HEX,HEX,BIN
! A19 - A0 D7-D0 I I M M A R I I UNUSED
! O O E E E E O O
! R W M M N S R C
! - - W R E D L
! - - T Y K
!
! WRITE CYCLE address $B8000, data $41
1 $B8000 $41 1 1 1 1 0 0 X X XXXX
Summary of Contents for 9100A Series
Page 6: ...vi ...
Page 8: ...viii ...
Page 10: ...x ...
Page 14: ...9100A 017 1 4 ...
Page 24: ...9100A 017 3 6 ...
Page 44: ...9100A 017 5 4 ...
Page 58: ...9100A 017 6 14 ...
Page 83: ...A 1 Appendix A New TL 1 Commands ...
Page 84: ...9100A 017 A 2 ...
Page 87: ...clockfreq 3 For More Information The Overview Of TL 1 section of the Programmer s Manual ...
Page 88: ...clockfreq 4 ...
Page 91: ...drivepoll 3 For More Information The Overview Of TL 1 section of the Programmer s Manual ...
Page 92: ...drivepoll 4 ...
Page 104: ...vectordrive 4 ...
Page 107: ...vectorload 3 For More Information The Overview Of TL 1 section of the Programmer s Manual ...
Page 108: ...vectorload 4 ...
Page 116: ...9100A 017 C 2 ...
Page 117: ...9100A 017 C 3 ...
Page 118: ...9100A 017 C 4 ...