C517A Datasheet, PDF (10/67 Pages) Siemens Semiconductor Group – 8-Bit CMOS Microcontroller

C517A
Table 2
Pin Definitions and Functions (cont’d)
Symbol
Pin Number I/O*) Function
P-MQFP-100
OWE
45
I
Oscillator Watchdog Enable
A high level on this pin enables the oscillator watchdog.
When left unconnected this pin is pulled high by a weak
internal pull-up resistor. The logic level at OWE should not
be changed during normal operation. When held at low
level the oscillator watchdog function is turned off. During
hardware power down the pullup resistor is switched off.
P6.0 - P6.7 46 - 50,
54 - 56
46
47
48
I/O Port 6
is a quasi-bidirectional I/O port with internal pull-up
resistors. Port 6 pins that have 1 s written to them are
pulled high by the internal pull-up resistors, and in that
state can be used as inputs. As inputs, port 6 pins being
externally pulled low will source current (I _IL, in the
DC characteristics) because of the internal pull-up
resistors.
Port 6 also contains the external A/D converter control pin
and the transmit and receive pins for the serial interface 1.
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 6,
as follows:
P6.0 ADST external A/D converter start pin
P6.1 RxD1 receiver data input of serial interface 1
P6.2 TxD1 transmitter data input of serial interface 1
P8.0 - P8.3 57 - 60
I
Port 8
is a 4-bit unidirectional input port. Port pins can be used for
digital input, if voltage levels meet the specified input high/
low voltages, and for the higher 4-bit of the multiplexed
analog inputs of the A/D converter, simultaneously.
P8.0 - P8.3 AIN8 - AIN11 analog input 8 - 14
RO
61
O Reset Output
This pin outputs the internally synchronized reset request
signal. This signal may be generated by an external
hardware reset, a watchdog timer reset or an oscillator
watchdog reset. The RO is active low.
*) I = Input
O = Output
Semiconductor Group
10
1997-10-01