80C186XL/80C188XL
80C186XL/80C188XL EXPRESS
80C186XL/80C188XL EXECUTION
TIMINGS
The Intel EXPRESS system offers enhancements to
the operational specifications of the 80C186XL mi-
croprocessor. EXPRESS products are designed to
meet the needs of those applications whose operat-
ing requirements exceed commercial standards.
A determination of program execution timing must
consider the bus cycles necessary to prefetch in-
structions as well as the number of execution unit
cycles necessary to execute instructions. The fol-
lowing instruction timings represent the minimum ex-
ecution time in clock cycles for each instruction. The
timings given are based on the following assump-
tions:
The 80C186XL EXPRESS program includes an ex-
tended temperature range. With the commercial
standard temperature range, operational character-
istics are guaranteed over the temperature range of
The opcode, along with any data or displacement
#
a
0 C to 70 C. With the extended temperature range
option, operational characteristics are guaranteed
§
§
required for execution of a particular instruction,
has been prefetched and resides in the queue at
the time it is needed.
b
a
over the range of 40 C to 85 C.
§
§
No wait states or bus HOLDs occur.
#
#
Package types and EXPRESS versions are identified
by a one or two-letter prefix to the part number. The
prefixes are listed in Table 10. All AC and DC specifi-
cations not mentioned in this section are the same
for both commercial and EXPRESS parts.
All word-data is located on even-address bound-
aries (80C186XL only).
All jumps and calls include the time required to fetch
the opcode of the next instruction at the destination
address.
Table 10. Prefix Identification
Package
Type
Temperature
Range
Prefix
All instructions which involve memory accesses can
require one or two additional clocks above the mini-
mum timings shown due to the asynchronous hand-
shake between the bus interface unit (BIU) and exe-
cution unit.
A
N
PGA
PLCC
LCC
Commercial
Commercial
Commercial
Commercial
Commercial
Extended
R
With a 16-bit BIU, the 80C186XL has sufficient bus
performance to ensure that an adequate number of
prefetched bytes will reside in the queue (6 bytes)
most of the time. Therefore, actual program execu-
tion time will not be substantially greater than that
derived from adding the instruction timings shown.
S
QFP
SB
TA
TN
TR
TS
SQFP
PGA
PLCC
LCC
Extended
Extended
The 80C188XL 8-bit BIU is limited in its performance
relative to the execution unit. A sufficient number of
prefetched bytes may not reside in the prefetch
queue (4 bytes) much of the time. Therefore, actual
program execution time will be substantially greater
than that derived from adding the instruction timings
shown.
QFP
Extended
41
ETC [ ETC ]
