C511 Datasheet, PDF (9/43 Pages) Siemens Semiconductor Group – 8-Bit CMOS Microcontroller

C511 / C513
Table 3
Pin Definitions and Functions (cont’d)
Symbol
P3.0-P3.7
Pin Number I/O*) Function
P-LCC- P-MQFP-
44
44
11,
13-19
5, 7-13
I/O Port 3
is a bidirectional I/O port with internal pull-up resistors.
Port 3 pins that have 1s 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_IL, in the DC characteristics)
because of the 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:
11
5
13
7
14
8
15
9
16
10
17
11
18
12
19
13
XTAL2
20
14
P3.0 RXD
P3.1 TXD
P3.2
P3.3
P3.4
P3.5
P3.6
INT0
INT1
T0
T1
WR
P3.7 RD
Receiver data input (asynchronous)
or data input/output (synchronous)
of serial interface (USART) ¹⁾
Transmitter data output (USART) ¹⁾
(asynchronous) or clock output
(synchronous) of serial interface
Interrupt 0 input / timer 0 gate control
Interrupt 1 input / timer 1 gate control
Counter 0 input
Counter 1 input
Write control signal : latches the data
byte from port 0 into the external
data memory
Read control signal : enables the
external data memory to port 0
1) _{not available in the C511/511A}
– XTAL2
Output of the inverting oscillator amplifier.
*) I = Input
O = Output
Semiconductor Group
9