SAB80C515-16-N SIEMENS [Siemens Semiconductor Group], SAB80C515-16-N Datasheet - Page 23

• Manufacturer Part Number: SAB80C515-16-N
• Description: 8-Bit CMOS Single-Chip Microcontroller
• Manufacturer: SIEMENS [Siemens Semiconductor Group]

I/O Ports
The SAB 80C515 has six 8-bit I/O ports and one 8-bit input port. Port 0 is an open-drain
bidirectional I/O port, while ports 1 to 5 are quasi-bidirectional I/O ports with internal pullup
resistors. That means, when configured as inputs, ports 1 to 5 will be pulled high and will source
current when externally pulled low. Port 0 will float when configured as input.
Port 0 and port 2 can be used to expand the program and data memory externally. During an
access to external memory, port 0 emits the low-order address byte and reads/writes the data
byte, while port 2 emits the high-order address byte. In this function, port 0 is not an open-drain
port, but uses a strong internal pullup FET. Ports 1 and 3 are provided for several alternate
functions, as listed below:
Port
P1.0
P1.1
P1.2
P1.3
P1.4
P1.5
P1.6
P1.7
P3.0
P3.1
P3.2
P3.3
P3.4
P3.5
P3.6
P3.7
The SAB 80C515 has dual-purpose input port. As the ANx lines in the SAB 80515 (NMOS
version), the eight port lines at port 6 can be used as analog inputs. But if the input voltages at
port 6 meet the specified digital input levels (V
input port. Reading the special function register P6 allows the user to input the digital values
currently applied to the port pins. It is not necessary to select these modes by software; the
voltages applied at port 6 pins can be converted to digital values using the A/D converter and
at the same time the pins can be read via SFR P6.
It must be noted, however, that the results in port P6 bits will be indeterminate if the levels at
the corresponding pins are not within their respective V
not possible to use port P6 as output lines. Special function register P6 is located at address
0DB
Semiconductor Group
H
.
Symbol
INT3/CC0
INT4/CC1
INT5/CC2
INT6/CC3
INT2
T2EX
CLKOUT
T2
R D
T D
INT0
INT1
T0
T1
WR
RD
Function
External interrupt 3 input, compare 0 output, capture 0 input
External interrupt 4 input, compare 1 output, capture 1 input
External interrupt 5 input, compare 2 output, capture 2 input
External interrupt 6 input, compare 3 output, capture 3 input
External interrupt 2 input
Timer 2 external reload trigger input
System clock output
Timer 2 external count or gate input
Serial port’s receiver data input (asynchronous) or data input/output
(synchronous)
Serial port’s transmitter data output (asynchronous) or clock output
(synchronous)
External interrupt 0 input, timer 0 gate control
External interrupt 1 input, timer 1 gate control
Timer 0 external counter input
Timer 1 external counter input
External data memory write strobe
External data memory read strobe
22
IL
an d V
IH
IL
), the port can also be used as digital
/ V
IH
specifications. Furthermore, it is
SAB 80C515/80C535