ATMEGA8HVD-4MX Atmel, ATMEGA8HVD-4MX Datasheet - Page 62

• Manufacturer Part Number: ATMEGA8HVD-4MX
• Description: MCU AVR 8K FLASH 2.1-8V 4MHZ QFN
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA8HVD-4MX

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 4MHz
• Peripherals: POR, WDT
• Number Of I /o: 5
• Program Memory Size: 8KB (4K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 256 x 8
• Ram Size: 512 x 8
• Voltage - Supply (vcc/vdd): 2 V ~ 2.4 V
• Data Converters: A/D 1x10b
• Oscillator Type: Internal
• Operating Temperature: -20°C ~ 85°C
• Package / Case: 18-MLF® Exposed Pad (Staggered Leads), DFN
• For Use With: ATSTK600 - DEV KIT FOR AVR/AVR32ATSTK500 - PROGRAMMER AVR STARTER KIT
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Connectivity: -

14.2
14.2.1
62
Low Voltage Ports as General Digital I/O
ATmega4HVD/8HVD
Configuring the Pin
Note that enabling the alternate function of some of the port pins does not affect the use of the
other pins in the port as general digital I/O.
The low voltage ports are bi-directional I/O ports with optional internal pull-ups.
shows a functional description of one I/O-port pin, here generically called Pxn.
Figure 14-2. General Low Voltage Digital I/O
Note:
Each port pin consists of three register bits: DDxn, PORTxn, and PINxn. As shown in
ter Description” on page
PORTxn bits at the PORTx I/O address, and the PINxn bits at the PINx I/O address.
The DDxn bit in the DDRx Register selects the direction of this pin. If DDxn is written logic one,
Pxn is configured as an output pin. If DDxn is written logic zero, Pxn is configured as an input
pin.
If PORTxn is written logic one when the pin is configured as an input pin, the pull-up resistor is
activated. To switch the pull-up resistor off, PORTxn has to be written logic zero or the pin has
to be configured as an output pin. The port pins are tri-stated when reset condition becomes
active, even if no clocks are running.
1. WRx, WPx, WDx, RRx, RPx, and RDx are common to all pins within the same port. clk
Pxn
SLEEP, and PUD are common to all ports.
PUD:
SLEEP:
clk
I/O
:
70, the DDxn bits are accessed at the DDRx I/O address, the
PULLUP DISABLE
SLEEP CONTROL
I/O CLOCK
SLEEP
(1)
SYNCHRONIZER
WDx:
RDx:
WRx:
RRx:
RPx:
WPx:
D
L
Q
Q
D
PINxn
WRITE DDRx
READ DDRx
WRITE PORTx
READ PORTx REGISTER
READ PORTx PIN
WRITE PINx REGISTER
Q
Q
RESET
RESET
PORTxn
Q
Q
Q
Q
DDxn
CLR
CLR
D
D
RRx
PUD
clk
WDx
RDx
RPx
1
0
I/O
WPx
WRx
8052B–AVR–09/08
Figure 14-2
”Regis-
I/O
,