ATmega128
Parity Checker
The parity checker is active when the high USART Parity mode (UPM1) bit is set. Type of parity
check to be performed (odd or even) is selected by the UPM0 bit. W hen enabled, the parity
checker calculates the parity of the data bits in incoming frames and compares the result with
the parity bit from the serial frame. The result of the check is stored in the receive buffer together
with the received data and stop bits. The Parity Error (UPE) flag can then be read by software to
check if the frame had a Parity Error.
The UPE bit is set if the next character that can be read from the receive buffer had a parIty
Error when received and the parity checking was enabled at that point (UPM1 = 1). This bit is
valid until the Receive buffer (UDR) is read.
Disabling the Receiver In contrast to the Transmitter, disabling of the Receiver will be immediate. Data from ongoing
receptions will therefore be lost. W hen disabled (i.e., the RXEN is set to zero) the receiver will no
longer override the normal function of the RxD port pin. The receiver buffer FIFO will be flushed
when the receiver is disabled. Remaining data in the buffer will be lost
Flushing the Receive
Buffer
The receiver buffer FIFO will be flushed when the receiver is disabled, i.e. the buffer will be emp-
tied of its contents. Unread data will be lost. If the buffer has to be flushed during normal
operation, due to for instance an error condition, read the UDR I/O location until the RXC flag is
cleared. The following code example shows how to flush the receive buffer.
Assembly Code Example (1)
USART_Flush:
sbis UCSRA, RXC
ret
in
r16, UDR
rjmp USART_Flush
C Code Example (1)
void USART_Flush( void )
{
unsigned char dummy;
while ( UCSRA & (1<<RXC) ) dummy = UDR;
}
Note:
1. “About Code Examples” on page 8 .
The USART includes a clock recovery and a data recovery unit for handling asynchronous
data reception. The clock recovery logic is used for synchronizing the internally generated
baud rate clock to the incoming asynchronous serial frames at the RxD pin. The data recovery
logic samples and low pass filters each incoming bit, thereby improving the noise immunity of
the receiver. The asynchronous reception operational range depends on the accuracy of the
internal baud rate clock, the rate of the incoming frames, and the frame size in number of bits.
183
2467X–AVR–06/11
相关PDF资料
ATMEGA64RZAPV-10AU BUNDLE ATMEGA644P/AT86RF230 TQFP
ATP101-TL-H MOSFET P-CH 30V 25A ATPAK
ATP102-TL-H MOSFET P-CH 30V 40A ATPAK
ATP103-TL-H MOSFET P-CH 30V 55A ATPAK
ATP104-TL-H MOSFET P-CH 30V 75A ATPAK
ATP106-TL-H MOSFET P-CH 40V 30A ATPAK
ATP107-TL-H MOSFET P-CH 40V 50A ATPAK
ATP108-TL-H MOSFET P-CH 40V 70A ATPAK
相关代理商/技术参数
ATMEGA128RFA1-ZUR SL514 制造商:Atmel Corporation 功能描述:
ATMEGA128RFA1-ZUR00 制造商:Atmel Corporation 功能描述:2.4GHZ 802.15.4 128K SOC REVF 制造商:Atmel Corporation 功能描述:2.4GHZ 802.15.4 128K SOC REVF T&R - Bulk 制造商:Atmel from Components Direct 功能描述:ATMEL ATMEGA128RFA1-ZUR00 MICROCONTROLLERS (MCU) 制造商:Atmel 功能描述:Atmel ATMEGA128RFA1-ZUR00 Microcontrollers (MCU) 制造商:Atmel Corporation 功能描述:MCU AVR 2.4GHZ 128K FLASH 64VQFN 制造商:Atmel Corporation 功能描述:2.4GHZ 802.15.4 128K SOC Revision F 制造商:Atmel 功能描述:2.4GHZ 802.15.4 128K SOC REVF
ATMEGA128RFR2-ZF 功能描述:IC RF TXRX+MCU 802.15.4 64-VFQFN 制造商:microchip technology 系列:- 包装:托盘 零件状态:在售 类型:TxRx + MCU 射频系列/标准:802.15.4 协议:Zigbee? 调制:DSSS, O-QPSK 频率:2.4GHz 数据速率(最大值):2Mbps 功率 - 输出:3.5dBm 灵敏度:-100dBm 存储容量:128kB 闪存,4kB EEPROM,16kB SRAM 串行接口:I2C,JTAG,SPI,USART GPIO:35 电压 - 电源:1.8 V ~ 3.6 V 电流 - 接收:5mA ~ 12.5mA 电流 - 传输:8mA ~ 14.5mA 工作温度:-40°C ~ 125°C 封装/外壳:64-VFQFN 裸露焊盘 标准包装:260
ATMEGA128RFR2-ZU 制造商:Atmel Corporation 功能描述:2.4GHZ 802.15.4 128K SOC IND 85C - Bulk
ATMEGA128RFR2-ZUR 制造商:Atmel Corporation 功能描述:2.4GHZ 802.15.4 128K SOC 85C T&R - Tape and Reel
ATMEGA128RZAV-8AU 功能描述:射频微控制器 - MCU AVR Z-Link Bundle RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:Si100x 数据总线宽度:8 bit 最大时钟频率:24 MHz 程序存储器大小:64 KB 数据 RAM 大小:4 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 85 C 封装 / 箱体:LGA-42 安装风格:SMD/SMT 封装:Tube
ATMEGA128RZAV-8MU 功能描述:射频微控制器 - MCU AVR Z-Link Bundle RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:Si100x 数据总线宽度:8 bit 最大时钟频率:24 MHz 程序存储器大小:64 KB 数据 RAM 大小:4 KB 片上 ADC:Yes 工作电源电压:1.8 V to 3.6 V 工作温度范围:- 40 C to + 85 C 封装 / 箱体:LGA-42 安装风格:SMD/SMT 封装:Tube