
C515C
Semiconductor Group
12
1997-07-01
HWPD
69
I
Hardware Power Down
A low level on this pin for the duration of one machine 
cycle while the oscillator is running resets the C515C.
A low level for a longer period will force the part to power 
down mode with the pins floating.
P4.0-P4.7
72-74, 76-80
72
73
74
76
77
78
79
80
I/O
Port 4
is an 8-bit quasi-bidirectional I/O port with internal pull-up 
resistors. Port 4 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 4 pins being 
externally pulled low will source current (
I
IL
, in the DC 
characteristics) because of the internal pull-up resistors.
P4 also contains the external A/D converter control pin, 
the SSC pins, the CAN controller input/output lines, and 
the external interrupt 8 input. The output latch 
corresponding to a secondary functionmust be 
programmed to a one (1) for that function to operate. 
The alternate functions are assigned to port 4 as follows:
P4.0
ADST
External A/D converter start pin
P4.1
SCLK
SSC Master Clock Output / 
SSC Slave Clock Input
P4.2
SRI
SSC Receive Input
P4.3
STO
SSC Transmit Output
P4.4
SLS
Slave Select Input
P4.5
INT8
External interrupt 8 input
P4.6
TXDC
Transmitter output of the CAN controller
P4.7
RXDC
Receiver input of the CAN controller
PE/SWD
75
I
Power saving mode
enable
 / 
Start watchdog timer
A low level on this pin allows the software to enter the 
power down, idle and slow down mode. In case the low 
level is also seen during reset, the watchdog timer 
function is off on default.
Use of the software controlled power saving modes is 
blocked, when this pin is held on high level. A high level 
during reset performs an automatic start of the watchdog 
timer immediately after reset. When left unconnected this 
pin is pulled high by a weak internal pull-up resistor.
*) I = Input
O = Output
Table 1 
Pin Definitions and Functions  (cont’d)
Symbol
Pin Number
I/O*)
Function
P-MQFP-80