- 您现在的位置：买卖IC网 > Sheet目录3769 > ATMEGA8515-16JUR (Atmel)MCU AVR 8KB FLASH 16MHZ 44PLCC
137
ATmega8515(L)
2512K–AVR–01/10
AVR USART vs. AVR UART –
Compatibility
The USART is fully compatible with the AVR UART regarding:
Bit locations inside all USART Registers
Baud Rate Generation
Transmitter Operation
Transmit Buffer Functionality
Receiver Operation
However, the receive buffering has two improvements that will affect the compatibility in
some special cases:
A second Buffer Register has been added. The two Buffer Registers operate as a
circular FIFO buffer. Therefore the UDR must only be read once for each incoming
data. More important is the fact that the Error Flags (FE and DOR) and the ninth
data bit (RXB8) are buffered with the data in the receive buffer. Therefore the status
bits must always be read before the UDR Register is read. Otherwise the error
status will be lost since the buffer state is lost.
The Receiver Shift Register can now act as a third buffer level. This is done by
allowing the received data to remain in the serial Shift Register (see Figure 64) if the
Buffer Registers are full, until a new start bit is detected. The USART is therefore
more resistant to Data OverRun (DOR) error conditions.
The following control bits have changed name, but have same functionality and register
location:
CHR9 is changed to UCSZ2
OR is changed to DOR
Clock Generation
The clock generation logic generates the base clock for the Transmitter and Receiver.
The USART supports four modes of clock operation: Normal asynchronous, Double
Speed asynchronous, Master synchronous and Slave synchronous mode. The UMSEL
bit in USART Control and Status Register C (UCSRC) selects between asynchronous
and synchronous operation. Double Speed (asynchronous mode only) is controlled by
the U2X found in the UCSRA Register. When using Synchronous mode (UMSEL = 1),
the Data Direction Register for the XCK pin (DDR_XCK) controls whether the clock
source is internal (Master mode) or external (Slave mode). The XCK pin is only active
when using Synchronous mode.
Figure 65 shows a block diagram of the clock generation logic.
Figure 65. Clock Generation Logic, Block Diagram
Prescaling
Down-counter
/2
UBRR
/4
/2
fosc
UBRR+1
Sync
Register
OSC
XCK
Pin
txclk
U2X
UMSEL
DDR_XCK
0
1
0
1
xcki
xcko
DDR_XCK
rxclk
0
1
0
Edge
Detector
UCPOL
发布紧急采购，3分钟左右您将得到回复。
相关PDF资料
PCA9555D/G-T
IC I/O EXPANDER I2C 16B 24SOIC
ATMEGA48-15AZV
MCU AVR 4K FLASH 15MHZ 32-TQFP
ATMEGA48-15AZ
MCU AVR 4K FLASH 15MHZ 32-TQFP
MIC74BQS
IC I/O EXPANDER I2C 8B 16QSOP
EXPANDIO-USB-PT-FS
IC I/O EXPANDER USB 32B 44TQFP
MAX7300ATL+
IC I/O EXPANDER 2WIRE 40TQFN
MAX7300ATL+T
IC I/O EXPANDER 2WIRE 40TQFN
MAX7300AAX+T
IC I/O EXPANDER I2C 28B 36SSOP
相关代理商/技术参数
ATmega8515-16MC
功能描述:8位微控制器 -MCU AVR 8K FLASH 512B EE SPI/UART/TWI 5V RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 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 + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT
ATmega8515-16MI
功能描述:8位微控制器 -MCU AVR 8K FLASH 512B EE SPI/UART/TWI 5V RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 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 + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT
ATMEGA8515-16MJ
功能描述:IC MCU AVR 8K 5V 16MHZ 44-QFN RoHS:是 类别:集成电路 (IC) >> 嵌入式 - 微控制器， 系列:AVR® ATmega 标准包装:9 系列:87C 核心处理器:8051 芯体尺寸:8-位 速度:40/20MHz 连通性:UART/USART 外围设备:POR，WDT 输入/输出数:32 程序存储器容量:32KB（32K x 8） 程序存储器类型:OTP EEPROM 大小:- RAM 容量:256 x 8 电压 - 电源 (Vcc/Vdd):4.5 V ~ 5.5 V 数据转换器:- 振荡器型:内部 工作温度:0°C ~ 70°C 封装/外壳:40-DIP（0.600"，15.24mm） 包装:管件
ATmega8515-16MU
功能描述:8位微控制器 -MCU AVR 8K FLASH 512B EE SPI/UART/TWI 5V RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 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 + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT
ATMEGA8515-16MUR
功能描述:8位微控制器 -MCU AVR 8KB FLSH 512B EE 512B SRAM-16MHz, IND RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 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 + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT
ATMEGA8515-16PC
功能描述:8位微控制器 -MCU AVR 8K FLASH 512B EE SPI/UART/TWI 5V RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 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 + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT
ATmega8515-16PI
功能描述:8位微控制器 -MCU AVR 8K FLASH 512B EE SPI/UART/TWI 5V RoHS:否 制造商:Silicon Labs 核心:8051 处理器系列:C8051F39x 数据总线宽度:8 bit 最大时钟频率:50 MHz 程序存储器大小:16 KB 数据 RAM 大小:1 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 + 105 C 封装 / 箱体:QFN-20 安装风格:SMD/SMT
ATMEGA8515-16PJ
功能描述:IC MCU AVR 8K 5V 16MHZ 40-DIP RoHS:是 类别:集成电路 (IC) >> 嵌入式 - 微控制器， 系列:AVR® ATmega 标准包装:9 系列:87C 核心处理器:8051 芯体尺寸:8-位 速度:40/20MHz 连通性:UART/USART 外围设备:POR，WDT 输入/输出数:32 程序存储器容量:32KB（32K x 8） 程序存储器类型:OTP EEPROM 大小:- RAM 容量:256 x 8 电压 - 电源 (Vcc/Vdd):4.5 V ~ 5.5 V 数据转换器:- 振荡器型:内部 工作温度:0°C ~ 70°C 封装/外壳:40-DIP（0.600"，15.24mm） 包装:管件