atmega103 ATMEL Corporation, atmega103 Datasheet - Page 98

• Manufacturer Part Number: atmega103
• Description: Atmega103 8-bit With 128k Bytes Of In-system Programmable Flash
• Manufacturer: ATMEL Corporation

Port E
98
ATmega103(L)
Figure 65. Port D Schematic Diagram (Pins PD6 and PD7)
Port E is an 8-bit bi-directional I/O port with internal pull-up resistors.
Three I/O memory address locations are allocated for the Port E, one each for the Data
Register – PORTE, $03($23), Data Direction Register – DDRE, $02($22) and the Port E
Input Pins – PINE, $01($21). The Port E Input Pins address is read-only, while the Data
Register and the Data Direction Register are read/write.
The Port E output buffers can sink 20 mA. As inputs, Port E pins that are externally
pulled low will source current if the pull-up resistors are activated.
All Port E pins have alternate functions as shown in Table 33.
Table 33. Port E Pin Alternate Functions
When the pins are used for the alternate function, the DDRE and PORTE Registers
have to be set according to the alternate function description.
Port Pin
PE0
PE1
PE2
PE3
PE4
PE5
PE6
PE7
PDn
Alternate Function
PDI/RXD (Programming Data Input or UART Receive Pin)
PDO/TXD (Programming Data Output or UART Transmit Pin)
AC+ (Analog Comparator Positive Input)
AC- (Analog Comparator Negative Input)
INT4 (External Interrupt4 Input)
INT5 (External Interrupt5 Input)
INT6 (External Interrupt6 Input)
INT7 (External Interrupt7 Input)
MOS
PULL-
UP
WP:
WD:
RL:
RP:
RD:
n:
m:
WRITE PORTD
WRITE DDRD
READ PORTD LATCH
READ PORTD PIN
READ DDRD
6, 7
1, 2
CSm2
SENSE CONTROL
CSm1
RL
RP
CSm0
Q
Q
PORTDn
RESET
RESET
DDDn
RD
WD
WP
R
C
R
C
TIMERm CLOCK
SOURCE MUX
D
D
0945I–AVR–02/07