![Intel 8XC196NT Скачать руководство пользователя страница 331](http://html1.mh-extra.com/html/intel/8xc196nt/8xc196nt_user-manual_2072210331.webp)
8XC196NT USER’S MANUAL
14-12
Figure 14-5. BUSWIDTH Timing Diagram
The BUSWIDTH signal can be used in numerous applications. For example, a system could store
code in a 16-bit memory device and data in an 8-bit memory device. The BUSWIDTH signal
could be tied to the chip-select input of the 8-bit memory device (shown in Figure 14-13 on page
14-26). When BUSWIDTH is low, it enables 8-bit bus mode and selects the 8-bit memory device.
When BUSWIDTH is high, it enables 16-bit bus mode and deselects the 8-bit memory device.
14.4.1 Timing Requirements for BUSWIDTH
When using BUSWIDTH to dynamically change between 8-bit and 16-bit bus widths, setup and
hold timings must be met for proper operation (see Figure 14-5). Because a decoded, valid ad-
dress is used to generate the BUSWIDTH signal, the setup time is specified relative to the address
being valid. This specification, T
AVGV
, indicates how much time one has to decode the valid ad-
dress and generate a valid BUSWIDTH signal.
BUSWIDTH must be held valid until the minimum hold specification, T
CLGX
, has been met. Typ-
ically this hold time is 0 ns minimum after CLKOUT goes low. In all cases, refer to the data sheet
for current specifications for T
AVGV
and T
CLGX
.
NOTE
Earlier HMOS devices used a BUSWIDTH setup timing that was referenced to
the falling edge of ALE (T
LLGV
). This specification is not meaningful for
CMOS devices, which use an internal two-phase clock; it is included for
comparison only.
T
LLGV
Bus
XTAL1
BUSWIDTH
ALE
CLKOUT
T
AVGV
T
CLGX
(MIN)
Valid
A0164-02
Address
Data
Содержание 8XC196NT
Страница 1: ...8XC196NT Microcontroller User s Manual...
Страница 2: ...8XC196NT Microcontroller User s Manual June 1995 Order Number 272317 003...
Страница 22: ...1 Guide to This Manual...
Страница 23: ......
Страница 35: ......
Страница 36: ...2 Architectural Overview...
Страница 37: ......
Страница 49: ......
Страница 50: ...3 Programming Considerations...
Страница 51: ......
Страница 66: ...4 Memory Partitions...
Страница 67: ......
Страница 104: ...5 Standard and PTS Interrupts...
Страница 105: ......
Страница 147: ......
Страница 148: ...6 I O Ports...
Страница 149: ......
Страница 176: ...7 Serial I O SIO Port...
Страница 177: ......
Страница 194: ...8 Synchronous Serial I O SSIO Port...
Страница 195: ......
Страница 211: ......
Страница 212: ...9 Slave Port...
Страница 213: ......
Страница 231: ......
Страница 232: ...10 Event Processor Array EPA...
Страница 233: ......
Страница 270: ...11 Analog to digital Converter...
Страница 271: ......
Страница 291: ......
Страница 292: ...12 Minimum Hardware Considerations...
Страница 293: ......
Страница 306: ...13 Special Operating Modes...
Страница 307: ......
Страница 317: ......
Страница 318: ...14 Interfacing with External Memory...
Страница 319: ......
Страница 362: ...15 Programming the Nonvolatile Memory...
Страница 363: ......
Страница 408: ...A Instruction Set Reference...
Страница 409: ......
Страница 476: ...B Signal Descriptions...
Страница 477: ......
Страница 493: ......
Страница 494: ...C Registers...
Страница 495: ......
Страница 565: ......
Страница 566: ...Glossary...
Страница 567: ......
Страница 580: ...Index...
Страница 581: ......
Страница 597: ......