C501_1 Datasheet, PDF (12/121 Pages) Siemens Semiconductor Group – 8-Bit Single-Chip Microcontroller

Introduction
C501
1.2 Pin Definitions and Functions
This section describes all external signals of the C501 with its function.
Table 1-1
Pin Definitions and Functions
Symbol
Pin Number
I/O*) Function
P-LCC-44 P-DIP-40 P-MQFP-44
P1.0 – P1.7 2–9
2
3
1–8
40–44,
I/O Port 1
1–3,
is a quasi-bidirectional I/O port with
internal pull-up resistors. Port 1 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 1 pins being externally pulled low will
source current (I_IL, in the DC character-
istics) because of the internal pull-up
resistors. Port 1 also contains the timer 2
pins as secondary function. The output
latch corresponding to a secondary
function must be pro-grammed to a one
(1) for that function to operate.
The secondary functions are assigned to
the pins of port 1, as follows:
1
40
P1.0 T2 Input to counter 2
2
41
P1.1 T2EX Capture - Reload trigger of
timer 2 / Up-Down count
*) I = Input
O = Output
Semiconductor Group
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