参数资料
型号: MR80C86/B
厂商: INTERSIL CORP
元件分类: 微控制器/微处理器
英文描述: 16-BIT, 5 MHz, MICROPROCESSOR, CQCC44
封装: CERAMIC, LCC-44
文件页数: 34/36页
文件大小: 693K
代理商: MR80C86/B
147
RQ/GT0
RQ/GT1
31, 30
I/O
REQUEST/GRANT: pins are used by other local bus masters to force the processor to release
the local bus at the end of the processor’s current bus cycle. Each pin is bidirectional with
RQ/GTO having higher priority than RQ/GT1. RQ/GT has an internal pull-up bus hold device so
it may be left unconnected. The request/grant sequence is as follows (see RQ/GT Sequence
Timing)
1. A pulse of 1 CLK wide from another local bus master indicates a local bus request (“hold”)
to the 80C86 (pulse 1).
2. During a T4 or TI clock cycle, a pulse 1 CLK wide from the 80C86 to the requesting master
(pulse 2) indicates that the 80C86 has allowed the local bus to float and that it will enter the
“grant sequence” state at the next CLK. The CPU’s bus interface unit is disconnected logi-
cally from the local bus during “grant sequence”.
3. A pulse 1 CLK wide from the requesting master indicates to the 80C86 (pulse 3) that the
“hold” request is about to end and that the 80C86 can reclaim the local bus at the next CLK.
The CPU then enters T4 (or TI if no bus cycles pending).
Each Master-Master exchange of the local bus is a sequence of 3 pulses. There must be one
idle CLK cycle after each bus exchange. Pulses are active low.
If the request is made while the CPU is performing a memory cycle, it will release the local
bus during T4 of the cycle when all the following conditions are met:
1. Request occurs on or before T2.
2. Current cycle is not the low byte of a word (on an odd address).
3. Current cycle is not the first acknowledge of an interrupt acknowledge sequence.
4. A locked instruction is not currently executing.
If the local bus is idle when the request is made the two possible events will follow:
1. Local bus will be released during the next cycle.
2. A memory cycle will start within three clocks. Now the four rules for a currently active memory
cycle apply with condition number 1 already satisfied.
LOCK
29
O
LOCK: output indicates that other system bus masters are not to gain control of the system bus
while LOCK is active LOW. The LOCK signal is activated by the “LOCK” prefix instruction and
remains active until the completion of the next instruction. This signal is active LOW, and is held
at a high impedance logic one state during “grant sequence”. In MAX mode, LOCK is automat-
ically generated during T2 of the first INTA cycle and removed during T2 of the second INTA
cycle.
QS1, QSO
24, 25
O
QUEUE STATUS: The queue status is valid during the CLK cycle after which the queue opera-
tion is performed.
QS1 and QS0 provide status to allow external tracking of the internal 80C86 instruction queue.
Note that QS1, QS0 never become high impedance.
Maximum Mode System (Continued)
The following pin function descriptions are for the 80C86 system in maximum mode (i.e., MN/MX - GND). Only the pin functions which are
unique to maximum mode are described below.
SYMBOL
PIN
NUMBER
TYPE
DESCRIPTION
QSI
QSO
00
No Operation
0
1
First byte of op code from queue
1
0
Empty the queue
1
Subsequent byte from queue
80C86
相关PDF资料
PDF描述
M41ST85WMH6 1 TIMER(S), REAL TIME CLOCK, PDSO28
MB90522PFV 16-BIT, MROM, 16 MHz, MICROCONTROLLER, PQFP120
ML63193-XXXTC 4-BIT, MROM, 2 MHz, MICROCONTROLLER, PQFP144
MB90F549GSPFF 16-BIT, FLASH, 16 MHz, MICROCONTROLLER, PQFP100
MPD78C12ALA-XXX 8-BIT, MROM, 15 MHz, MICROCONTROLLER, PQCC68
相关代理商/技术参数
参数描述
MR80C88 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:CMOS 8/16-Bit Microprocessor
MR80C88-2 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:CMOS 8/16-Bit Microprocessor
MR80C88-2B 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:CMOS 8/16-Bit Microprocessor
MR80C88B 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:CMOS 8/16-Bit Microprocessor
MR811 制造商:Motorola Inc 功能描述: