ATMEGA644PV-20AU Atmel, ATMEGA644PV-20AU Datasheet - Page 179
![IC MCU AVR 64K FLASH 44-TQFP](/photos/6/70/67042/313-44-tqfp_sml.jpg)
ATMEGA644PV-20AU
Manufacturer Part Number
ATMEGA644PV-20AU
Description
IC MCU AVR 64K FLASH 44-TQFP
Manufacturer
Atmel
Series
AVR® ATmegar
Specifications of ATMEGA644PV-20AU
Core Processor
AVR
Core Size
8-Bit
Speed
20MHz
Connectivity
I²C, SPI, UART/USART
Peripherals
Brown-out Detect/Reset, POR, PWM, WDT
Number Of I /o
32
Program Memory Size
64KB (32K x 16)
Program Memory Type
FLASH
Eeprom Size
2K x 8
Ram Size
4K x 8
Voltage - Supply (vcc/vdd)
1.8 V ~ 5.5 V
Data Converters
A/D 8x10b
Oscillator Type
Internal
Operating Temperature
-40°C ~ 85°C
Package / Case
44-TQFP, 44-VQFP
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
- Current page: 179 of 439
- Download datasheet (10Mb)
16.7.3
8011O–AVR–07/10
Transmitter Flags and Interrupts
Notes:
The ninth bit can be used for indicating an address frame when using multi processor communi-
cation mode or for other protocol handling as for example synchronization.
The USART Transmitter has two flags that indicate its state: USART Data Register Empty
(UDREn) and Transmit Complete (TXCn). Both flags can be used for generating interrupts.
The Data Register Empty (UDREn) Flag indicates whether the transmit buffer is ready to receive
new data. This bit is set when the transmit buffer is empty, and cleared when the transmit buffer
contains data to be transmitted that has not yet been moved into the Shift Register. For compat-
ibility with future devices, always write this bit to zero when writing the UCSRnA Register.
When the Data Register Empty Interrupt Enable (UDRIEn) bit in UCSRnB is written to one, the
USART Data Register Empty Interrupt will be executed as long as UDREn is set (provided that
global interrupts are enabled). UDREn is cleared by writing UDRn. When interrupt-driven data
Assembly Code Example
C Code Example
USART_Transmit:
void USART_Transmit( unsigned int data )
{
}
; Wait for empty transmit buffer
sbis UCSRnA,UDREn
rjmp USART_Transmit
; Copy 9th bit from r17 to TXB8
cbi
sbrc r17,0
sbi
; Put LSB data (r16) into buffer, sends the data
out
ret
/* Wait for empty transmit buffer */
while ( !( UCSRnA & (1<<UDREn))) )
/* Copy 9th bit to TXB8 */
UCSRnB &= ~(1<<TXB8);
if ( data & 0x0100 )
/* Put data into buffer, sends the data */
UDRn = data;
1. These transmit functions are written to be general functions. They can be optimized if the con-
2. See “About Code Examples” on page 8.
UCSRnB |= (1<<TXB8);
tents of the UCSRnB is static. For example, only the TXB8 bit of the UCSRnB Register is used
after initialization.
UCSRnB,TXB8
UCSRnB,TXB8
UDRn,r16
;
(1)(2)
(1)(2)
ATmega164P/324P/644P
179
Related parts for ATMEGA644PV-20AU
Image
Part Number
Description
Manufacturer
Datasheet
Request
R
![ATmega644P](/images/manufacturer_photos/0/0/79/atmel_corporation_tmb.jpg)
Part Number:
Description:
Manufacturer:
Atmel Corporation
Datasheet:
![ATmega644P Automotive](/images/manufacturer_photos/0/0/79/atmel_corporation_tmb.jpg)
Part Number:
Description:
Manufacturer:
Atmel Corporation
Datasheet:
![ATMEGA644P-20AU](/photos/6/70/67042/313-44-tqfp_tmb.jpg)
Part Number:
Description:
IC MCU AVR 64K FLASH 44-TQFP
Manufacturer:
Atmel
Datasheet:
![ATMEGA644P-20MU](/photos/12/13/121316/313-44-qfn_tmb.jpg)
Part Number:
Description:
IC MCU AVR 64K FLASH 44-QFN
Manufacturer:
Atmel
Datasheet:
![ATMEGA644P-20AQ](/photos/6/70/67042/313-44-tqfp_tmb.jpg)
Part Number:
Description:
MCU AVR 64K FLASH 20MHZ 44-TQFP
Manufacturer:
Atmel
Datasheet:
![ATMEGA644P-A15MZ](/photos/12/13/121316/313-44-qfn_tmb.jpg)
Part Number:
Description:
MCU AVR 64KB FLASH 16MHZ 44QFN
Manufacturer:
Atmel
Datasheet:
![ATMEGA644P-20PU](/photos/6/70/67049/453-40-dip_tmb.jpg)
Part Number:
Description:
IC MCU AVR 64K FLASH 40-DIP
Manufacturer:
Atmel
Datasheet:
![ATMEGA644P-20AUR](/images/manufacturer_photos/0/0/78/atmel_tmb.jpg)
Part Number:
Description:
MCU AVR 64K FLASH 20MHZ 44TQFP
Manufacturer:
Atmel
Datasheet:
![ATMEGA644P-20MUR](/images/manufacturer_photos/0/0/78/atmel_tmb.jpg)
Part Number:
Description:
MCU AVR 64K FLASH 20MHZ 44QFN
Manufacturer:
Atmel
Datasheet:
![ATMEGA644P-20MQ](/photos/12/13/121316/313-44-qfn_tmb.jpg)
Part Number:
Description:
MCU AVR 64K FLASH 20MHZ 44-QFN
Manufacturer:
Atmel
Datasheet:
![ATMEGA644P-20PQ](/photos/6/70/67049/453-40-dip_tmb.jpg)
Part Number:
Description:
MCU AVR 64K FLASH 20MHZ 40-PDIP
Manufacturer:
Atmel
Datasheet: