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14-37
INTERFACING WITH EXTERNAL MEMORY
Figure 14-23. Mode 1 System Bus Timing
14.8.4 Mode 2, Long Read/Write with Early Address
Mode 2 (Figure 14-24) is similar to mode 1 in that RD#, WR#, and ALE begin ½ T
OSC
earlier in
the bus cycle and the widths of RD# and WR# are 1 T
OSC
longer than in mode 3. It differs from
mode 1 in that the address is also placed onto the bus ½ T
OSC
earlier in the bus cycle. The T
RLDV
timing is 1 T
OSC
longer, the T
AVDV
timing is ½ T
OSC
longer, and T
RHDZ
is ½ T
OSC
shorter in mode 2
than in mode 3. This mode trades a longer T
AVDV
for a shorter T
RHDZ
.
XTAL 1
CLKOUT
T
CLCL
T
LHLH
T
RHLH
T
RLRH
T
LLRL
T
LHLL
T
RLDV
T
RHDZ
T
LLAX
T
AVLL
T
AVDV
T
LLWL
T
WLWH
Address Out
Data Out
T
QVWH
T
WHQX
T
OSC
T
CLLL
Data In D15:0
T
CHLH
Address
T
XHCH
T
CHCL
Bus Write
AD15:0
8- and 16-bit
Bus Mode
T
WHBX
, T
RHBX
T
WHAX
, T
RHAX
T
WHIX
, T
RHIX
AD15:8
INST
BHE Valid
INST Valid
T
RLAZ
ALE/ADV#
RD#
AD15:8 Valid 8-bit Bus Mode
BHE#
WR#
Bus Read
AD15:0
8- and16-bit
Bus Mode
A3098-01
Summary of Contents for 8XC196NT
Page 1: ...8XC196NT Microcontroller User s Manual...
Page 2: ...8XC196NT Microcontroller User s Manual June 1995 Order Number 272317 003...
Page 22: ...1 Guide to This Manual...
Page 23: ......
Page 35: ......
Page 36: ...2 Architectural Overview...
Page 37: ......
Page 49: ......
Page 50: ...3 Programming Considerations...
Page 51: ......
Page 66: ...4 Memory Partitions...
Page 67: ......
Page 104: ...5 Standard and PTS Interrupts...
Page 105: ......
Page 147: ......
Page 148: ...6 I O Ports...
Page 149: ......
Page 176: ...7 Serial I O SIO Port...
Page 177: ......
Page 194: ...8 Synchronous Serial I O SSIO Port...
Page 195: ......
Page 211: ......
Page 212: ...9 Slave Port...
Page 213: ......
Page 231: ......
Page 232: ...10 Event Processor Array EPA...
Page 233: ......
Page 270: ...11 Analog to digital Converter...
Page 271: ......
Page 291: ......
Page 292: ...12 Minimum Hardware Considerations...
Page 293: ......
Page 306: ...13 Special Operating Modes...
Page 307: ......
Page 317: ......
Page 318: ...14 Interfacing with External Memory...
Page 319: ......
Page 362: ...15 Programming the Nonvolatile Memory...
Page 363: ......
Page 408: ...A Instruction Set Reference...
Page 409: ......
Page 476: ...B Signal Descriptions...
Page 477: ......
Page 493: ......
Page 494: ...C Registers...
Page 495: ......
Page 565: ......
Page 566: ...Glossary...
Page 567: ......
Page 580: ...Index...
Page 581: ......
Page 597: ......