- 您现在的位置：买卖IC网 > Sheet目录3769 > ATMEGA8515-16JUR (Atmel)MCU AVR 8KB FLASH 16MHZ 44PLCC
112
ATmega8515(L)
2512K–AVR–01/10
are enabled, the interrupt handler routine can be used for updating the TOP and com-
pare values.
When changing the TOP value the program must ensure that the new TOP value is
higher or equal to the value of all of the compare registers. If the TOP value is lower
than any of the compare registers, a Compare Match will never occur between the
TCNT1 and the OCR1x. Note that when using fixed TOP values the unused bits are
masked to zero when any of the OCR1x Registers are written.
The procedure for updating ICR1 differs from updating OCR1A when used for defining
the TOP value. The ICR1 Register is not double buffered. This means that if ICR1 is
changed to a low value when the counter is running with none or a low prescaler value,
there is a risk that the new ICR1 value written is lower than the current value of TCNT1.
The result will then be that the counter will miss the Compare Match at the TOP value.
The counter will then have to count to the MAX value (0xFFFF) and wrap around start-
ing at 0x0000 before the Compare Match can occur. The OCR1A Register however, is
double buffered. This feature allows the OCR1A I/O location to be written anytime.
When the OCR1A I/O location is written the value written will be put into the OCR1A
Buffer Register. The OCR1A Compare Register will then be updated with the value in
the Buffer Register at the next timer clock cycle the TCNT1 matches TOP. The update is
done at the same timer clock cycle as the TCNT1 is cleared and the TOV1 Flag is set.
Using the ICR1 Register for defining TOP works well when using fixed TOP values. By
using ICR1, the OCR1A Register is free to be used for generating a PWM output on
OC1A. However, if the base PWM frequency is actively changed (by changing the TOP
value), using the OCR1A as TOP is clearly a better choice due to its double buffer
feature.
In fast PWM mode, the compare units allow generation of PWM waveforms on the
OC1x pins. Setting the COM1x1:0 bits to 2 will produce a non-inverted PWM and an
inverted PWM output can be generated by setting the COM1x1:0 to 3 (See Table on
page 119). The actual OC1x value will only be visible on the port pin if the data direction
for the port pin is set as output (DDR_OC1x). The PWM waveform is generated by set-
ting (or clearing) the OC1x Register at the Compare Match between OCR1x and
TCNT1, and clearing (or setting) the OC1x Register at the timer clock cycle the counter
is cleared (changes from TOP to BOTTOM).
The PWM frequency for the output can be calculated by the following equation:
The N variable represents the prescaler divider (1, 8, 64, 256, or 1024).
The extreme values for the OCR1x Register represents special cases when generating
a PWM waveform output in the fast PWM mode. If the OCR1x is set equal to BOTTOM
(0x0000) the output will be a narrow spike for each TOP+1 timer clock cycle. Setting the
OCR1x equal to TOP will result in a constant high or low output (depending on the polar-
ity of the output set by the COM1x1:0 bits.)
A frequency (with 50% duty cycle) waveform output in fast PWM mode can be achieved
by setting OC1A to toggle its logical level on each Compare Match (COM1A1:0 = 1).
This applies only if OCR1A is used to define the TOP value (WGM1 = 15). The wave-
form generated will have a maximum frequency of f
OC1A = fclk_I/O/2 when OCR1A is set to
zero (0x0000). This feature is similar to the OC1A toggle in CTC mode, except the dou-
ble buffer feature of the output compare unit is enabled in the fast PWM mode.
f
OCnxPWM
f
clk_I/O
N
1
TOP
+
()
-----------------------------------
=
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