Rainbow Electronics ATtiny2313 - Manual (Page 52)

52
ATtiny2313
2543A–AVR–08/03
Alternate Port Functions Most port pins have alternate functions in addition to being general digital I/Os. Figure
25 shows how the port pin control signals from the simplified Figure 22 can be overrid-
den by alternate functions. The overriding signals may not be present in all port pins, but
the figure serves as a generic description applicable to all port pins in the AVR micro-
controller family.
Figure 25. Alternate Port Functions (1)
Note: 1. WRx, WPx, WDx, RRx, RPx, and RDx are common to all pins within the same port.
clk
I/O
, SLEEP, and PUD are common to all ports. All other signals are unique for each
pin.
Table 24 summarizes the function of the overriding signals. The pin and port indexes
from Figure 25 are not shown in the succeeding tables. The overriding signals are gen-
erated internally in the modules having the alternate function.
clk
RPx
RRx
WRx
RDx
WDx
PUD
SYNCHRONIZER
WDx: WRITE DDRx
WRx: WRITE PORTx
RRx: READ PORTx REGISTER
RPx: READ PORTx PIN
PUD: PULLUP DISABLE
clk
I/O
: I/O CLOCK
RDx: READ DDRx
D
L
Q
Q
SET
CLR
0
1
0
1
0
1
DIxn
AIOxn
DIEOExn
PVOVxn
PVOExn
DDOVxn
DDOExn
PUOExn
PUOVxn
PUOExn: Pxn PULL-UP OVERRIDE ENABLE
PUOVxn: Pxn PULL-UP OVERRIDE VALUE
DDOExn: Pxn DATA DIRECTION OVERRIDE ENABLE
DDOVxn: Pxn DATA DIRECTION OVERRIDE VALUE
PVOExn: Pxn PORT VALUE OVERRIDE ENABLE
PVOVxn: Pxn PORT VALUE OVERRIDE VALUE
DIxn: DIGITAL INPUT PIN n ON PORTx
AIOxn: ANALOG INPUT/OUTPUT PIN n ON PORTx
RESET
RESET
Q
Q D
CLR
Q
Q D
CLR
Q
Q D
CLR
PINxn
PORTxn
DDxn
D
ATA
B
U
S
0
1
DIEOVxn
SLEEP
DIEOExn: Pxn DIGITAL INPUT-ENABLE OVERRIDE ENABLE
DIEOVxn:
Pxn DIGITAL INPUT-ENABLE OVERRIDE VALUE
SLEEP: SLEEP CONTROL
Pxn
I/O
0
1
PTOExn
WPx
PTOExn: Pxn, PORT TOGGLE OVERRIDE ENABLE
WPx: WRITE PINx