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AT90S8414
Preliminary
4-59
THE PORT A DATA REGISTER - PORTA
Bit
7
6
5
4
3
2
1
0
$1B
PORTA7
PORTA6
PORTA5
PORTA4
PORTA3
PORTA2
PORTA1
PORTA0
PORTA
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Initial value
0
0
0
0
0
0
0
0
THE PORT A DATA DIRECTION REGISTER - DDRA
Bit
7
6
5
4
3
2
1
0
$1A
DDA7
DDA6
DDA5
DDA4
DDA3
DDA2
DDA1
DDA0
DDRA
Read/Write
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Initial value
0
0
0
0
0
0
0
0
THE PORT A INPUT PINS ADDRESS - PINA
Bit
7
6
5
4
3
2
1
0
$19
PINA7
PINA6
PINA5
PINA4
PINA3
PINA2
PINA1
PINA0
PINA
Read/Write
R
R
R
R
R
R
R
R
Initial value
Hi-Z
Hi-Z
Hi-Z
Hi-Z
Hi-Z
Hi-Z
Hi-Z
Hi-Z
The Port A Input Pins address - PINA - is not a register, and this address enables access to the physical value on each
Port A pin. When reading PORTA the PORTA Data Latch is read, and when reading PINA, the logical values present on
the pins are read.
PORTA AS GENERAL DIGITAL I/O
All 8 bits in PORT A are equal when used as digital I/O pins.
PAn, General I/O pin: The DDAn bit in the DDRA register selects the direction of this pin, if DDAn is set (one), PAn is
configured as an output pin. If DDAn is cleared (zero), PAn is configured as an input pin. If PORTAn is set (one) when
the pin configured as an input pin, the MOS pull up resistor is activated. To switch the pull up resistor off, the PORTAn
has to be cleared (zero) or the pin has to be configured as an output pin.
Table 16: DDAn Effects on PORT A Pins
DDAn
PORTAn
I/O
Pull up
Comment
0
0
Input
No
Tri-state (Hi-Z)
0
1
Input
Yes
PAn will source current (IIL) if ext. pulled low.
1
0
Output
No
Push-Pull Zero Output
1
1
Output
No
Push-Pull One Output
n: 7,6…0, pin number.
Содержание AT90S8414
Страница 4: ...4 4 AT90S8414 Preliminary...
Страница 6: ...4 6 AT90S8414 Preliminary Block Diagram Figure 1 The AT90S8414 Block Diagram...
Страница 65: ...AT90S8414 Preliminary 4 65 Figure 50 PORTB Schematic Diagram Pin PB5 Figure 51 PORTB Schematic Diagram Pin PB6...
Страница 68: ...4 68 AT90S8414 Preliminary Figure 53 PORTC Schematic Diagram Pins PC0 PC7...
Страница 87: ...AT90S8414 Preliminary 4 87...