C508_01 Datasheet, PDF (16/267 Pages) Infineon Technologies AG – 8-Bit CMOS Microcontroller

C508
Introduction
Table 1-1 Pin Definitions and Functions (cont’d)
Symbol
Pin Numbers
I/O¹⁾ Function
P-MQFP-64 P-SDIP-64
P2.0-P2.7 54 - 47
62 - 55
I/O Port 2
is an 8-bit quasi-bidirectional I/O port with internal
pull-up transistors. Port 2 pins that have 1’s written
to them are pulled high by the internal pull-up
resistors, and in that state can be used as inputs. As
inputs, Port 2 pins being externally pulled low will
source current (I_IL, in the DC characteristics)
because of the internal pull-up transistors.
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
uses strong internal pull-up transistors when issuing
1’s. During accesses to external data memory that
use 8-bit addresses (MOVX @Ri), Port 2 issues the
contents of the P2 special function register and uses
only the internal pull-up transistors.
As I/O functions, Port 2 pins also have LED drive
capability of up to 10 mA sinking current per pin.
XTAL1 42
50
I XTAL1
Input to the inverting oscillator amplifier and input to
the internal clock generator circuits.
To drive the device from an external clock source,
XTAL1 should be driven, while XTAL2 is left
unconnected.
Minimum and maximum high and low times as well
as rise/fall times specified in the AC characteristics
must be observed.
XTAL2 41
49
O XTAL2
Output of the inverting oscillator amplifier.
P4.0-P4.7 5 - 12
13 - 20
I Port 4
is an 8-bit uni-directional input port to the A/D
converter. Port 4 pins can be used for digital input,
if voltage levels simultaneously meet the
specifications for high/low input voltages and for the
eight multiplexed analog inputs.
User’s Manual
1-8
2001-05