SAB80C517A-N18 Siemens Semiconductor Group, SAB80C517A-N18 Datasheet - Page 12

• Manufacturer Part Number: SAB80C517A-N18
• Description: 8-Bit CMOS Single-Chip Microcontroller
• Manufacturer: Siemens Semiconductor Group

Pin Definitions and Functions (cont’d)
Symbol
XTAL2
XTAL1
P2.0 - P2.7 41 - 48
*
Semiconductor Group
I = Input
O = Output
P-LCC-84
39
40
Pin Number
P-MQFP-100-2
12
13
14 - 21
I/O
–
–
I/O
11
*)
Function
XTAL2
Input to the inverting oscillator amplifier and
input to the internal clock generator circuits.
XTAL1
Output of the inverting oscillator amplifier.
To drive the device from an external clock
source, XTAL2 should be driven, while
XTAL1 is left unconnected. There are no
requirements on the duty cycle of the
external clock signal, since the input to the
internal clocking circuitry is devided down
by a divide-by-two flip-flop. Minimum and
maximum high and low times as well as
rise/fall times specified in the AC
characteristics must be observed.
Port 2
is a bidirectional I/O port with internal pull-
up resistors. 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 in-puts. As inputs, port 2
pins being externally pulled low will source
current (I
because of the internal pull-up resistors.
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 resistors when
issuing1 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.
IL
SAB 80C517A/83C517A-5
, in the DC characteristics)
1994-05-01