參數(shù)資料
型號: MD80C51
廠商: Intel Corp.
英文描述: CHMOS SINGLE-CHIP 8-BIT MICROCONTROLLER
中文描述: CHMOS單片8位微控制器
文件頁數(shù): 5/16頁
文件大?。?/td> 229K
代理商: MD80C51
AUTOMOTIVE 80C31BH/80C51BH/87C51
Port 3 also serves the functions of various special
features of the MCS 51 microcontroller family, as
listed below:
Pin
Name
Alternate Function
P3.0
P3.1
P3.2
P3.3
P3.4
P3.5
P3.6
P3.7
RXD
TXD
INT0
INT1
T0
T1
WR
RD
Serial Input Line
Serial Output Line
External Interrupt 0
External Interrupt 1
Timer 0 External Input
Timer 1 External Input
External Data Memory Write Strobe
External Data Memory Read Strobe
Port 3 also receives some control signals for
EPROM programming and program verification.
RESET:
Reset input. A logic high on this pin for two
machine cycles while the oscillator is running resets
the device. An internal pulldown resistor permits a
power-on reset to be generated using only an exter-
nal capacitor to V
CC
.
ALE/PROG (EPROM Only):
Address Latch Enable
output signal for latching the low byte of the address
during accesses to external memory. This pin is also
the program pulse input (PROG) during EPROM pro-
gramming.
In normal operation ALE is emitted at a constant
rate of 1/6 the oscillator frequency, and may be
used for external timing or clocking purposes. Note,
however, that one ALE pulse is skipped during each
access to external Data Memory.
PSEN:
Program Store Enable is the Read strobe
to
External
Program
87C51/80C51BH is executing from Internal Program
Memory, PSEN is inactive (high). When the device is
executing code from External Program Memory,
PSEN is activated twice each machine cycle, except
that two PSEN activations are skipped during each
access to External Data Memory.
Memory.
When
the
EA/V
PP
:
External Access enable. EA must be
strapped
to
V
SS
in
87C51/80C51BH to fetch code from External Pro-
gram Memory locations starting at 0000H up to
0FFFFH.
[
Note, however, that if either of the Lock
Bits is programmed, the logic level at EA is internally
latched during reset.
]
(EPROM only.)
order
to
enable
the
EA must be strapped to V
CC
for internal program
execution.
V
PP
(EPROM Only):
This pin also receives the
12.75V programming supply voltage (V
PP
) during
EPROM programming.
270419–5
Figure 4. Using the On-Chip Oscillator
270419–6
Figure 5. External Clock Drive
XTAL1
: Input to the inverting oscillator amplifier and
input to the internal clock generating circuits.
XTAL2
: Output from the inverting oscillator amplifi-
er.
OSCILLATOR CHARACTERISTICS
XTAL1 and XTAL2 are the input and output, respec-
tively, of an inverting amplifier which can be config-
ured for use as an on-chip oscillator, as shown in
Figure 4.
To drive the device from an external clock source,
XTAL1 should be driven, while XTAL2 is left uncon-
nected, as shown in Figure 5. There are no require-
ments on the duty cycle of the external clock signal,
since the input to the internal clocking circuitry is
through a divide-by-two flip-flop, but minimum and
maximum high and low times specified on the Data-
sheet must be observed.
IDLE MODE
In Idle Mode, the CPU puts itself to sleep while all
the on-chip peripherals remain active. The mode is
invoked by software. The content of the on-chip
RAM and all the Special Functions Registers remain
unchanged during this mode. The Idle Mode can be
terminated by any enabled interrupt or by a hard-
ware reset.
It should be noted that when Idle is terminated by a
hardware reset, the device normally resumes pro-
gram execution, from where it left off, up to two ma-
chine cycles before the internal reset algorithm
takes control. On-chip hardware inhibits access to
5
相關(guān)PDF資料
PDF描述
MD8284N Clock Generator and Driver for 8066, 8088 Processors
MD8284N-1 Clock Generator and Driver for 8066, 8088 Processors
MD8284N-1B Clock Generator and Driver for 8066, 8088 Processors
MD8284NB Clock Generator and Driver for 8066, 8088 Processors
MD8286 OCTAL BUS TRANSCEIVER
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MD80C51BH 制造商:ROCHESTER 制造商全稱:ROCHESTER 功能描述:CMOS SINGLE - CHIP 8-BIT MICROCOMPUTER 64K program Memory Space
MD80C51FB 制造商:Rochester Electronics LLC 功能描述:
MD80C86 制造商:INTERSIL 制造商全稱:Intersil Corporation 功能描述:CMOS 16-Bit Microprocessor
MD80C862 制造商:Intel 功能描述:PROCESSOR:MICRO-PROCESSOR
MD80C86-2 制造商:INTERSIL 制造商全稱:Intersil Corporation 功能描述:CMOS 16-Bit Microprocessor