ATmega64A
13.3.1
Alternate Functions of Port A
The Port A has an alternate function as the address low byte and data lines for the External
Memory Interface.
Table 13-3. Port A Pins Alternate Functions
Port Pin
PA7
Alternate Function
AD7 (External memory interface address and data bit 7)
AD6 (External memory interface address and data bit 6)
AD5 (External memory interface address and data bit 5)
AD4 (External memory interface address and data bit 4)
AD3 (External memory interface address and data bit 3)
AD2 (External memory interface address and data bit 2)
AD1 (External memory interface address and data bit 1)
AD0 (External memory interface address and data bit 0)
PA6
PA5
PA4
PA3
PA2
PA1
PA0
Table 13-4 and Table 13-5 relates the alternate functions of Port A to the overriding signals
shown in Figure 13-5 on page 73.
Table 13-4. Overriding Signals for Alternate Functions in PA7:PA4
Signal
Name
PUOE
PUOV
PA7/AD7
PA6/AD6
PA5/AD5
PA4/AD4
SRE
SRE
SRE
SRE
~(WR | ADA(1)) •
PORTA7 • PUD
~(WR | ADA) •
PORTA6 • PUD
~(WR | ADA) •
PORTA5 • PUD
~(WR | ADA) •
PORTA4 • PUD
DDOE
DDOV
PVOE
PVOV
SRE
WR | ADA
SRE
SRE
WR | ADA
SRE
SRE
WR | ADA
SRE
SRE
WR | ADA
SRE
A7 • ADA | D7 OUTPUT
• WR
A6 • ADA | D6
OUTPUT • WR
A5 • ADA | D5
OUTPUT • WR
A4 • ADA | D4
OUTPUT • WR
0
0
0
0
DIEOE
DIEOV
DI
0
D7 INPUT
–
0
D6 INPUT
–
0
D5 INPUT
–
0
D4 INPUT
–
AIO
75
8160C–AVR–07/09
ATMEL [ ATMEL ]
