at43usb355 ATMEL Corporation, at43usb355 Datasheet - Page 72

• Manufacturer Part Number: at43usb355
• Description: At43usb355 Full-speed Usb Microcontroller With Embedded Hub, Adc And Pwm
• Manufacturer: ATMEL Corporation

Port F
72
AT43USB355
In the AT43USB355 Port F[1:3] is a 3-bit bi-directional I/O. Its output buffers can sink or source
2 mA Three I/O memory address locations are allocated for the Port F, one each for the Data
Register (PORTF), $06($26), Data Direction Register (DDRF), $05($25) and the Port F Input
Pins (PIND), $04($24). The Port F Input Pins address is read only, while the Data Register
and the Data Direction Register are read/write.
PF1 to PF3 pins have individually selectable pull-up resistors. When pins PPF1 to PF3 are
used as inputs and are externally pulled low, they will source current if the internal pull-up
resistors are activated.
In the SRAM version of the chip, the AT43USB355E, Port F is used for program memory
downloading immediately after power-on reset. After downloading is completed, PF0 is driven
high, while PF[1:3] becomes available as GPIO. In both versions of the chip, PF3 can be pro-
grammed as ICP, Timer/Counter 1 Input Capture.
Port F Data Register – PORTF
Port F Data Direction Register – DDRF
Port F Input Pins Address – PINF
The Port F Input Pins address (PINF) is not a register, and this address enables access to the
physical value on each Port F pin. When reading PORTF, the Port F Data Latch is read, and
when reading PINF, the logical values present on the pins are read.
Initial Value
Initial Value
Read/Write
Initial Value
Read/Write
Read/Write
$06 ($26)
$05 ($25)
$04 ($24)
Bit
Bit
Bit
N/A
R
R
R
7
–
0
7
–
0
7
–
N/A
R
R
6
–
0
6
–
0
6
–
R
N/A
R
R
5
–
0
5
–
0
R
5
–
N/A
R
4
–
0
4
–
R
0
R
4
–
PORTF3
PINF3
DDF3
R/W
R/W
N/A
R
3
0
3
0
3
PORTF2
PINF2
DDF2
R/W
R/W
N/A
2
R
2
0
2
0
PORTF1
PINF1
DDF1
R/W
R/W
N/A
R
1
0
1
0
1
N/A
2603G–USB–04/06
R
R
R
0
–
0
0
–
0
0
–
DDRF
PINF
PORTF