ATMEGA64A-MNR Atmel, ATMEGA64A-MNR Datasheet - Page 184

• Manufacturer Part Number: ATMEGA64A-MNR
• Description: IC MCU AVR 64K FLASH 8QFN
• Manufacturer: Atmel
• Series: AVR® ATmegar

Specifications of ATMEGA64A-MNR

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: I²C, SPI, UART/USART
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 53
• 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): 2.7 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: *
• Core: AVR8
• Data Bus Width: 8 bit
• Data Ram Size: 2 KB
• Interface Type: SPI, UART, I2C
• Maximum Clock Frequency: 16 MHz
• Number Of Programmable I/os: 53
• Operating Supply Voltage: 2.7 V to 5.5 V
• Maximum Operating Temperature: + 105 C
• Mounting Style: SMD/SMT
• Operating Temperature Range: - 40 C to + 85 C
• Processor To Be Evaluated: ATMEGA64A
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

20.7.2
8160C–AVR–07/09
Receiving Frames with 9 Data Bits
The following code example shows a simple USART receive function based on polling of the
Receive Complete n (RXCn) flag. When using frames with less than eight bits the most signifi-
cant bits of the data read from the UDRn will be masked to zero. The USART has to be initialized
before the function can be used.
Note:
The function simply waits for data to be present in the receive buffer by checking the RXCn flag,
before reading the buffer and returning the value.
If 9-bit characters are used (UCSZn=7) the ninth bit must be read from the RXB8n bit in
UCSRnB before reading the low bits from the UDR. This rule applies to the FEn, DORn, and
UPE status flags as well. Read status from UCSRnA, then data from UDRn. Reading the UDRn
I/O location will change the state of the receive buffer FIFO and consequently the TXB8n, FEn,
DORn, and UPEn bits, which all are stored in the FIFO, will change. The following code example
shows a simple USART receive function that handles both nine bit characters and the status
bits.
Assembly Code Example
C Code Example
USART_Receive:
unsigned char USART_Receive( void )
{
}
; Wait for data to be received
sbis UCSRnA, RXCn
rjmp USART_Receive
; Get and return received data from buffer
in
ret
/* Wait for data to be received */
while ( !(UCSRnA & (1<<RXCn)) )
/* Get and return received data from buffer */
return UDRn;
1. See “About Code Examples” on page 8.
r16, UDRn
;
(1)
(1)
ATmega64A
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