attiny261a-xu ATMEL Corporation, attiny261a-xu Datasheet - Page 67

• Manufacturer Part Number: attiny261a-xu
• Description: 8-bit Avr Microcontroller With 2/4/8k Bytes In-system Programmable Flash
• Manufacturer: ATMEL Corporation

10.3
10.3.1
10.3.2
10.3.3
8197B–AVR–01/10
Register Description
MCUCR – MCU Control Register
PORTA – Port A Data Register
DDRA – Port A Data Direction Register
Table 10-8.
Note:
• Bit 6 – PUD: Pull-up Disable
When this bit is written to one, the pull-ups in the I/O ports are disabled even if the DDxn and
PORTxn Registers are configured to enable the pull-ups ({DDxn, PORTxn} = 0b01). See
figuring the Pin” on page 54
Bit
0x35 (0x55)
Read/Write
Initial Value
Bit
0x1B (0x3B)
Read/Write
Initial Value
Bit
0x1A (0x3A)
Read/Write
Initial Value
Signal
Name
PUOE
PUOV
DDOE
DDOV
PVOE
PVOV
PTOE
DIEOE
DIEOV
DI
AIO
1. INTRC means that one of the internal oscillators is selected (by the CKSEL fuses), EXTCK
means that external clock is selected (by the CKSEL fuses).
PB3/OC1B/
PCINT11
0
0
0
0
OC1B Enable
OC1B
0
PCINT11 • PCIE
0
PCINT11
7
BODS
R/W
0
7
PORTA7
R/W
0
7
DDA7
R/W
0
Overriding Signals for Alternate Functions in PB3:PB0
6
PUD
R/W
0
6
PORTA6
R/W
0
6
DDA6
R/W
0
for more details about this feature.
PB2/SCK/USCK/SCL/O
C1B/PCINT10
0
0
USI_TWO_WIRE •
USIPOS
(USI_SCL_HOLD +
PORTB2) • DDB2 •
USIPOS
OC1B Enable + USIPOS
• USI_TWO_WIRE •
DDB2
OC1B
USITC • USIPOS
PCINT10 • PCIE +
USISIE • USIPOS
0
USCK/SCL/PCINT10
5
PORTA5
R/W
0
5
DDA5
R/W
0
5
SE
R/W
0
4
PORTA4
R/W
0
4
DDA4
R/W
0
4
SM1
R/W
0
3
PORTA3
R/W
0
3
DDA3
R/W
0
3
SM0
R/W
0
PB1/MISO/DO/OC1A/
PCINT9
0
0
0
0
OC1A Enable +
USIPOS •
USI_THREE_WIRE
OC1A + (DO •
USIPOS)
0
PCINT9 • PCIE
0
PCINT9
2
PORTA2
R/W
0
2
DDA2
R/W
0
2
BODSE
R/W
0
1
PORTA1
R/W
0
1
DDA1
R/W
0
1
ISC01
R
0
PB0/MOSI/DI/SDA/
OC1A/PCINT8
0
0
USI_TWO_WIRE •
USIPOS
(SDA + PORTB0) •
DDB0 • USIPOS
OC1A Enable +
(USI_TWO_WIRE •
DDB0 • USIPOS)
OC1A
0
PCINT8 • PCIE +
(USISIE • USIPOS)
0
DI/SDA/PCINT8
0
PORTA0
R/W
0
0
DDA0
R/W
0
0
ISC00
R
0
MCUCR
PORTA
DDRA
“Con-
67