Rainbow Electronics Atmega169L - Manual (Page 237)

237
ATmega169V/L
2514A–AVR–08/02
Figure 109. General Port Pin Schematic Diagram
Scanning the RESET Pin The RESET pin accepts 5V active low logic for standard reset operation, and 12V active
high logic for High Voltage Parallel programming. An observe-only cell as shown in Fig-
ure 110 is inserted both for the 5V reset signal; RSTT, and the 12V reset signal;
RSTHV.
Figure 110. Observe-only Cell
CLK
RPx
RRx
WPx
RDx
WDx
PUD
SYNCHRONIZER
WDx: WRITE DDRx
WPx: WRITE PORTx
RRx: READ PORTx REGISTER
RPx: READ PORTx PIN
PUD: PULLUP DISABLE
CLK : I/O CLOCK
RDx: READ DDRx
D
L
Q
Q
RESET
RESET
Q
Q D
Q
Q D
CLR
PORTxn
Q
Q D
CLR
DDxn
PINxn
DA
T
A
B
U
S
SLEEP
SLEEP: SLEEP CONTROL
Pxn
I/O
I/O
See Boundary-scan
Description for Details!
PUExn
OCxn
ODxn
IDxn
PUExn: PULLUP ENABLE for pin Pxn
OCxn: OUTPUT CONTROL for pin Pxn
ODxn: OUTPUT DATA to pin Pxn
IDxn: INPUT DATA from pin Pxn
0
1
D Q
From
Previous
Cell
ClockDR
ShiftDR
To
Next
Cell
From System Pin To System Logic
FF1