8031AH_95 Datasheet, PDF (3/11 Pages) Intel Corporation – NMOS SINGLE-CHIP 8-BIT MICROCONTROLLERS

AUTOMOTIVE MICROCONTROLLER MCS 51
Resident in 8052 8032 only
Figure 2 MCS 51 Microcontroller Block Diagram
270499 – 2
PIN DESCRIPTIONS
V_CC
Supply voltage
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
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
3