ATA8742 ATMEL Corporation, ATA8742 Datasheet - Page 87

• Manufacturer Part Number: ATA8742
• Manufacturer: ATMEL Corporation

19.4
19.4.1
19.4.2
19.4.3
19.4.4
19.4.5
19.4.6
9151A–INDCO–07/09
Register Description
MCUCR – MCU Control Register
PORTA – Port A Data Register
DDRA – Port A Data Direction Register
PINA – Port A Input Pins Address
PORTB – Port B Data Register
DDRB – Port B Data Direction Register
• Bits 7, 2– Res: Reserved Bits
These bits are reserved bits in the ATtiny24/44/84 and will always read as zero.
• 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 73
Bit
Read/Write
Initial Value
Bit
0x1B (0x3B)
Read/Write
Initial Value
Bit
0x1A (0x3A)
Read/Write
Initial Value
Bit
0x19 (0x39)
Read/Write
Initial Value
Bit
0x18 (0x38)
Read/Write
Initial Value
Bit
0x17 (0x37)
Read/Write
Initial Value
PORTA7
PINA7
DDA7
R/W
R/W
R/W
R
7
–
0
R
R
7
0
7
0
7
0
7
0
7
0
–
–
PORTA6
PINA6
DDA6
PUD
R/W
R/W
R/W
R/W
R
R
6
0
6
0
6
0
6
0
6
–
0
6
–
0
for more details about this feature.
PORTA5
PINA5
DDA5
R/W
R/W
R/W
N/A
R/W
R
R
5
0
5
0
5
0
SE
5
0
5
5
0
PORTA4
PINA4
DDA4
R/W
R/W
R/W
N/A
R
R
4
0
4
0
4
4
0
4
0
SM1
R/W
4
0
PORTB3
PORTA3
DDA3
PINA3
DDB3
R/W
R/W
R/W
R/W
R/W
N/A
3
0
3
0
3
0
3
0
3
SM0
R/W
3
0
PORTB2
PORTA2
PINA2
DDA2
DDB2
R/W
R/W
R/W
R/W
R/W
N/A
2
0
2
0
2
0
2
0
2
R
2
–
0
PORTB1
PORTA1
DDA1
PINA1
DDB1
R/W
R/W
R/W
R/W
R/W
ISC01
N/A
1
0
1
0
1
0
1
0
1
R
1
0
ATA8742
PORTB0
PORTA0
PINA0
DDB0
DDA0
ISC00
R/W
R/W
R/W
R/W
R/W
N/A
0
0
0
0
0
0
R
0
0
0
0
0
MCUCR
PORTB
PORTA
DDRB
DDRB
PINB
“Con-
87