Intel MCS 51 User Manual

8051, 8052 AND 80C51
HARDWARE DESCRIPTION
INTRODUCTION
This
chapter preaentsa comprehensivedescriptionof
the on-chiphardwarefeaturesof the MCS@-51micro-
controller. Includedin this descriptionare
● The port drivers and how they function both as
ports and, for Ports Oand 2, in bus operations
● The Timer/Counters
● The SerialInterface
● The Interrupt System
● Reset
. The ReducedPowerModesin the CHMOSdevices
● The EPROMversionsofthe 8051AH, 8052AHand
80C51BH
The devicesunder considerationare listedin Table 1.
As it becomesunwieldyto be constantlyreferring to
eachof thesedevicesbytheir individualnam~ wewill
adopt a convcmtionof referringto them genericallyas
8051sand 8052s,unlessa specificmemberofthe group
is beingreferredto, in whichcaseit willbe specifically
named. The “8051s”include the 8051AH, 80C51BH,
andtheir ROMlessand EPROMversions.The “8052s”
are the 8052AH,8032AHand 8752BH.
Figure 1showsa functionalblockdiagramofthe 8051s
and 8052s.
Table1.The
MCS-51 Family of Mien
[
Devioe ROMleaa EPROM
ROM
1
Name
I
Version Veraion Bytes
8051AH 8031AH
8751H, 8751BH 4K
8052AH 8032AH
8752BH 8K
80C51BH 80C31BH 87C51
4K
SpecialFunctionRegisters
ontroiiera
m
A map ofthe on-chipmemoryarea calledSFR(SpecialFunctionRegister)spaceis shownin Figure2.SFRSmarked
by parenthesesare residentin the 8052sbut not in the 8051s.
3-3

Intel MCS 51 Specifications

General

Brand	Intel
Model	MCS 51
Category	Microcontrollers
Language	English