SAH-C515 SIEMENS [Siemens Semiconductor Group], SAH-C515 Datasheet - Page 13

• Manufacturer Part Number: SAH-C515
• Description: 8-Bit CMOS Microcontroller
• Manufacturer: SIEMENS [Siemens Semiconductor Group]

Table 1-1
Pin Definitions and Functions (cont’d)
Symbol
P3.0-P3.7
Semiconductor Group
*) I = Input
O = Output
21-28
21
22
23
24
25
26
27
28
Number
P-LCC-
Pin
68
15-22
15
16
17
18
19
20
21
22
P-MQFP-
Number
Pin
80
I/O*) Function
I/O
Port 3
is an 8-bit quasi-bidirectional I/O port with internal
pullup resistors. Port 3 pins that have 1's written to
them are pulled high by the internal pullup resistors,
and in that state can be used as inputs. As inputs,
port 3 pins being externally pulled low will source
current ( I
internal pullup resistors. Port 3 also contains the
interrupt, timer, serial port and external memory
strobe pins that are used by various options. The
output latch corresponding to a secondary function
must be programmed to a one (1) for that function to
operate. The secondary functions are assigned to
the pins of port 3 as follows:
P3.0 / RxD
data
interface
P3.1 / TxD
interface
P3.2 / INT0
P3.3 / INT1
P3.4 / T0
P3.5 / T1
P3.6 / WR
byte
P3.7 / RD
1-7
IL
, in the DC characteristics) because of the
Receiver data input (asynch.) or
input/output (synch.) of serial
Transmitter data output (asynch.) or
clock output (synch.) of serial
External interrupt 0 input /
timer 0 gate control input
External interrupt 1 input /
timer 1 gate control input
Timer 0 counter input
Timer 1 counter input
WR control output; latches the data
from port 0 into the external data
memory
RD control output; enables the
external data memory
Introduction
C515