ATMEGA645A-AU Atmel, ATMEGA645A-AU Datasheet - Page 178

• Manufacturer Part Number: ATMEGA645A-AU
• Description: IC MCU AVR 64K FLASH 64TQFP
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA645A-AU

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: SPI, UART/USART, USI
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 54
• 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: 64-TQFP
• Processor Series: ATmega
• Core: AVR
• Data Bus Width: 8 bit
• Data Ram Size: 4 KB
• Interface Type: SPI, USART
• Maximum Clock Frequency: 16 MHz
• Number Of Programmable I/os: 54
• Number Of Timers: 3
• Operating Supply Voltage: 3.3 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Operating Temperature Range: - 40 C to + 85 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

178
ATmega165A/165PA/325A/325PA/3250A/3250PA/645A/645P/645
show a transmit function that handles 9-bit characters. For the assembly code, the data to be
sent is assumed to be stored in registers R17:R16.
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.
Assembly Code Example
C Code Example
USART_Transmit:
void USART_Transmit( unsigned int data )
{
}
; Wait for empty transmit buffer
sbis UCSR0A,UDRE0
rjmp USART_Transmit
; Copy 9th bit from r17 to TXB80
cbi
sbrc r17,0
sbi
; Put LSB data (r16) into buffer, sends the data
sts
ret
/* Wait for empty transmit buffer */
while ( !( UCSR0A & (1<<UDRE0))) )
/* Copy 9th bit to TXB8n */
UCSR0B &= ~(1<<TXB80);
if ( data & 0x0100 )
/* Put data into buffer, sends the data */
UDR0 = data;
1. These transmit functions are written to be general functions. They can be optimized if the con-
2.
UCSR0B |= (1<<TXB80);
See ”About Code Examples” on page 9.
tents of the UCSRnB is static. For example, only the TXB8n bit of the UCSRnB Register is
used after initialization.
UCSR0B,TXB80
UCSR0B,TXB80
UDR0,r16
;
(1)(2)
(1)(2)
8285B–AVR–03/11