AT90S8515

Manufacturer Part NumberAT90S8515
Description8-bit microcontroller with 8K bytes in-system programmable flash, 2.7-6.0V
ManufacturerATMEL Corporation
AT90S8515 datasheet
 
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Page 73/112:

Port D Data Register PORTD

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Port D Data Register – PORTD
Port D Data Direction Register
– DDRD
Port D Input Pins Address –
PIND
Port D as General Digital I/O
Alternate Functions of Port D
0841G–09/01
Bit
7
6
5
$12 ($32)
PORTD7
PORTD6
PORTD5
Read/Write
R/W
R/W
R/W
Initial Value
0
0
0
Bit
7
6
5
$11 ($31)
DDD7
DDD6
DDD5
Read/Write
R/W
R/W
R/W
Initial Value
0
0
0
Bit
7
6
5
$10 ($30)
PIND7
PIND6
PIND5
Read/Write
R
R
R
Initial Value
N/A
N/A
N/A
The Port D Input Pins address (PIND) is not a register; this address enables access to
the physical value on each Port D pin. When reading PORTD, the Port D Data Latch is
read and when reading PIND, the logical values present on the pins are read.
PDn, general I/O pin: The DDDn bit in the DDRD register selects the direction of this pin.
If DDDn is set (one), PDn is configured as an output pin. If DDDn is cleared (zero), PDn
is configured as an input pin. If PDn is set (one) when configured as an input pin, the
MOS pull-up resistor is activated. To switch the pull-up resistor off the PDn has to be
cleared (zero) or the pin has to be configured as an output pin. The Port D pins are tri-
stated when a reset condition becomes active, even if the clock is not active.
Table 24. DDDn Bits on Port D Pins
DDDn
PORTDn
I/O
0
0
Input
0
1
Input
1
0
Output
1
1
Output
Note:
n: 7,6…0, pin number.
• RD – Port D, Bit 7
RD is the external data memory read control strobe. See “Interface to External SRAM”
on page 60 for detailed information.
• WR – Port D, Bit 6
WR is the external data memory write control strobe. See “Interface to External SRAM”
on page 60 for detailed information.
• OC1A – Port D, Bit 5
OC1A: Output compare match output. The PD5 pin can serve as an external output
when the Timer/Counter1 compare matches. The PD5 pin has to be configured as an
output (DDD5 set [one]) to serve this function. See the Timer/Counter1 description for
further details and how to enable the output. The OC1A pin is also the output pin for the
PWM mode timer function.
AT90S8515
4
3
2
1
PORTD4
PORTD3
PORTD2
PORTD1
R/W
R/W
R/W
R/W
0
0
0
0
4
3
2
1
DDD4
DDD3
DDD2
DDD1
R/W
R/W
R/W
R/W
0
0
0
0
4
3
2
1
PIND4
PIND3
PIND2
PIND1
R
R
R
R
N/A
N/A
N/A
N/A
Pull-up
Comment
No
Tri-state (high-Z)
Yes
PDn will source current if ext. pulled low.
No
Push-pull Zero Output
No
Push-pull One Output
0
PORTD0
PORTD
R/W
0
0
DDD0
DDRD
R/W
0
0
PIND0
PIND
R
N/A
73