C504 Datasheet, PDF (8/49 Pages) Siemens Semiconductor Group – 8-Bit CMOS Microcontroller

C504
Table 1
Pin Definitions and Functions (cont’d)
Symbol
P3.0-P3.7
Pin Number I/O
(P-MQFP-44) *)
5, 7-13
I/O
5
7
8
9
10
11
12
13
CTRAP
6
I
*) I = Input
O = Output
Function
Port 3
is an 8-bit bidirectional port. P3.0 (R×D) and P3.1 (T×D)
operate as defined for the C501. P3.2 to P3.7 contain the
external interrupt inputs, timer inputs, input and as an
additional optinal function four of the analog inputs of the
A/D-converter. Port 3 pins are assigned to be used as
analog inputs via the bits of SFR P3ANA.
P3.6/WR can be assigned as a third interrupt input. The
functions are assigned to the pins of port 3 as follows:
P3.0 / RxD
Receiver data input (asynch.) or data
input/output (synch.) of serial
interface
P3.1 / TxD
Transmitter data output (asynch.) or
clock output (synch.) of serial
interface
P3.2 / AN4 / INT0 Analog input channel 4 / external
interrupt 0 input / timer 0 gate control
input
P3.3 / AN5 / INT1 Analog input channel 5 / external
interrupt 1 input / timer 1 gate control
input
P3.4 / AN6 / T0 Analog input channel 6 / timer 0
counter input
P3.5 / AN7 / T1 Analog input channel 7 / timer 1
counter input
P3.6 / WR / INT2 WR control output; latches the data
byte from port 0 into the external data
memory /
external interrupt 2 input
P3.7 / RD
RD control output; enables the
external data memory
CCU Trap Input
With CTRAP = low the compare outputs of the CAPCOM
unit are switched to the logic level as defined in the COINI
register (if they are enabled by the bits in SFR TRCON).
CTRAP is an input pin with an internal pullup resistor. For
power saving reasons, the signal source which drives the
CTRAP input should be at high or floating level during
power-down mode.
Semiconductor Group
8