Rainbow Electronics AT90LS8535 - Manual (Page 85)

85
AT90S/LS8535
1041H–11/01
Alternate Functions of Port C When the AS2 bit in ASSR is set (one) to enable asynchronous clocking of
Timer/Counter2, pins PC6 and PC7 are disconnected from the port. In this mode, a
crystal oscillator is connected to the pins and the pins cannot be used as I/O pins.
Port C Schematics Note that all port pins are synchronized. The synchronization latch is, however, not
shown in the figure.
Figure 58. Port C Schematic Diagram (Pins PC0 - PC5)
Figure 59. Port C Schematic Diagram (Pins PC6)
DA
TA
B
U
S
D
D
Q
Q
RESET
RESET
C
C
WD
WP
RD
MOS
PULL-
UP
PCn
R
R
WP:
WD:
RL:
RP:
RD:
n: WRITE PORTC
WRITE DDRC
READ PORTC LATCH
READ PORTC PIN
READ DDRC
0-5
DDCn
PORTCn
RL
RP
DA
TA
B
U
S
D
D
Q
Q
RESET
RESET
C
C
WD
WP
RD
MOS
PULL-
UP
PC6
R
R
WP:
WD:
RL:
RP:
RD:
AS2: WRITE PORTC
WRITE DDRC
READ PORTC LATCH
READ PORTC PIN
READ DDRC
ASYNCH SELECT T/C2
DDC6
PORTC6
RL
RP
AS2
T/C2 OSC
AMP INPUT