The MCS 51 microcontroller products are optimized for control applications Byte-processing and numerical
operations on small data structures are facilitated by a variety of fast addressing modes for accessing the
internal RAM The instruction set provides a convenient menu of 8-bit arithmetic instructions including multiply
and divide instructions Extensive on-chip support is provided for one-bit variables as a separate data type
allowing direct bit manipulation and testing in control and logic systems that require Boolean processing
Device
8052AH
8051AH
8032AH
8031AH
Internal Memory
Program
8K x 8 ROM
4K x 8 ROM
none
none
Data
256 x 8 RAM
128 x 8 RAM
256 x 8 RAM
128 x 8 RAM
Timers
Event Counters
3 x 16-Bit
2 x 16-Bit
3 x 16-Bit
2 x 16-Bit
Interrupts
6
5
6
5
NOTICE
This datasheet contains information on products in full production Specifications within this datasheet
are subject to change without notice Verify with your local Intel sales office that you have the latest
datasheet before finalizing a design
Other brands and names are the property of their respective owners
Information in this document is provided in connection with Intel products Intel assumes no liability whatsoever including infringement of any patent or
copyright for sale and use of Intel products except as provided in Intel’s Terms and Conditions of Sale for such products Intel retains the right to make
changes to these specifications at any time without notice Microcomputer Products may have minor variations to this specification known as errata
COPYRIGHT
INTEL CORPORATION 1995
February 1995
Order Number 270499-006
AUTOMOTIVE MICROCONTROLLER MCS 51
the extended temperature range option operational
characteristics are guaranteed over the temperature
range of
b
40 C to
a
85 C ambient For the automo-
tive temperature range option operational charac-
teristics are guaranteed over the temperature range
of
b
40 C to
a
110 C ambient
The automotive extended and commercial temper-
ature versions of the MCS 51 microcontroller prod-
uct families are available with or without burn-in op-
tions
PRODUCT OPTIONS
Intel’s extended and automotive temperature range
products are designed to meet the needs of those
applications whose operating requirements exceed
commercial standards
With the commercial standard temperature range
operational characteristics are guaranteed over the
temperature range of 0 C to
a
70 C ambient With
270499 –1
Example
P 80A51AH indicates an automotive temperature range version of the 8051AH in a PDIP package with 4 Kbyte ROM
program memory
Figure 1 MCS 51 Microcontroller Product Family Nomenclature
Table 1 Temperature Options
Temperature
Classification
Extended
Automotive
Temperature
Designation
T
L
A
Operating
Temperature
C Ambient
b
40 to
a
85
b
40 to
a
85
b
40 to
a
110
Burn-In
Option
Standard
Extended
Standard
2
AUTOMOTIVE MICROCONTROLLER MCS 51
270499 –2
Resident in 8052 8032 only
Figure 2 MCS 51 Microcontroller Block Diagram
PIN DESCRIPTIONS
V
CC
Supply voltage
Port 0 pins that have 1s written to them float and in
that state can be used as high-impedance inputs
Port 0 is also the multiplexed low-order address and
data bus during accesses to external Program and
Data Memory In this application it uses strong inter-
nal pullups when emitting 1s and can source and
sink 8 LS TTL inputs
Port 0 also outputs the code bytes during program
verification of the ROM External pullups are re-
quired
V
SS
Circuit ground
Port 0
Port 0 is an 8-bit open drain bidirectional I O port As
an output port each pin can sink 8 LS TTL inputs
3
AUTOMOTIVE MICROCONTROLLER MCS 51
Diagrams are for pin reference only Package sizes are not to scale
270499 – 3
EPROM only
Pin (DIP)
Figure 3 MCS 51 Microcontroller Connections
Port 1
Port 1 is an 8-bit bidirectional I O port with internal
pullups The Port 1 output buffers can sink source 4
LS TTL inputs Port 1 pins that have 1s written to
them are pulled high by the internal pullups and in
that state can be used as inputs As inputs Port 1
pins that are externally pulled low will source current
(I
IL
on the datasheet) because of the internal pull-
ups
Port 1 also receives the low-order address bytes
during program verification of the ROM
In the 8032AH and 8052AH Port 1 pins P1 0 and
P1 1 also serve the T2 and T2EX functions respec-
tively
uses strong internal pullups when emitting 1s Dur-
ing accesses to external Data Memory that use 8-bit
addresses (MOVX Ri) Port 2 emits the contents of
the P2 Special Function Register
Port 2 also receives the high-order address bits dur-
ing program verification of the ROM
Port 3
Port 3 is an 8-bit bidirectional I O port with internal
pullups The Port 3 output buffers can sink source 4
LS TTL inputs Port 3 pins that have 1s written to
them are pulled high by the internal pullups and in
that state can be used as inputs As inputs Port 3
pins that are externally pulled low will source current
(I
IL
on the datasheet) because of the pullups
Port 3 also serves the functions of various special
features of the MCS 51 microcontroller family as
listed below
Port
Pin
P3 0
P3 1
P3 2
P3 3
P3 4
P3 5
P3 6
P3 7
Alternative Function
RXD (serial input port)
TXD (serial output port)
INT0 (external interrupt 0)
INT1 (external interrupt 1)
T0 (Timer 0 external input)
T1 (Timer 1 external input)
WR (external data memory write strobe)
RD (external data memory read strobe)
Port 2
Port 2 is an 8-bit bidirectional I O port with internal
pullups The Port 2 output buffers can sink source 4
LS TTL inputs Port 2 pins that have 1s written to
them are pulled high by the internal pullups and in
that state can be used as inputs As inputs Port 2
pins that are externally pulled low will source current
(I
IL
on the datasheet) because of the internal pull-
ups
Port 2 emits the high-order address byte during
fetches from external Program Memory and during
accesses to external Data Memory that use 16-bit
addresses (MOVX DPTR) In this application it
4
AUTOMOTIVE MICROCONTROLLER MCS 51
RESET
Reset input A high on this pin for two machine cy-
cles while the oscillator is running resets the device
XTAL1
Input to the inverting oscillator amplifier
ALE PROG
Address Latch Enable output pulse for latching the
low byte of the address during accesses to external
memory
In normal operation ALE is emitted at a constant
rate of
the oscillator frequency and may be used
for external timing or clocking purposes Note how-
ever that one ALE pulse is skipped during each ac-
cess to external Data Memory
XTAL2
Output from the inverting oscillator amplifier
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 Either a quartz crystal or ceramic resonator
may be used More detailed information concerning
the use of the on-chip oscillator is available in Appli-
cation Note AP-155 ‘‘Oscillators for Microcontrol-
lers ’’
To drive the device from an external clock source
XTAL1 should be grounded while XTAL2 is driven
as shown in Figure 5 There are no requirements 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 datasheet must
be observed
PSEN
Program Store Enable is the read strobe to external
Program Memory
When the device is executing code from external
Program Memory PSEN is activated twice each ma-
chine cycle except that two PSEN activations
are skipped during each access to external Data
Memory
EA V
PP
External Access enable EA must be strapped to V
SS
in order to enable any MCS 51 microcontroller de-
vice to fetch code from external Program memory
locations 0 to 0FFFH (0 to 1FFFH in the 8032AH
and 8052AH)
270499 –6
Figure 5 External Drive Configuration
270499 –5
C1 C2
e
30 pF
g
10 pF for Crystals
For Ceramic Resonators contact resonator manufacturer
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