f OCnxPCPWM = ----------------------------
ATmega128
the counter decrements. The P W M frequency for the output when using phase correct P W M can
be calculated by the following equation:
f clk_I/O
2 ? N ? TOP
The N variable represents the prescaler divider (1, 8, 64, 256, or 1024).
The extreme values for the OCRnx Register represents special cases when generating a P W M
waveform output in the phase correct P W M mode. If the OCRnx is set equal to BOTTOM the
output will be continuously low and if set equal to TOP the output will be continuously high for
non-inverted P W M mode. For inverted P W M the output will have the opposite logic values.
If OCnA is used to define the TOP value ( W GMn3:0 = 11) and COMnA1:0 = 1, the OCnA Output
will toggle with a 50% duty cycle.
Phase and Frequency
Correct PWM Mode
The phase and frequency correct Pulse Width Modulation, or phase and frequency correct P W M
mode ( W GMn3:0 = 8 or 9) provides a high resolution phase and frequency correct P W M wave-
R PFCPWM = ----------------------------------
form generation option. The phase and frequency correct P W M mode is, like the phase correct
P W M mode, based on a dual-slope operation. The counter counts repeatedly from BOTTOM
(0x0000) to TOP and then from TOP to BOTTOM. In non-inverting Compare Output mode, the
output compare (OCnx) is cleared on the compare match between TCNTn and OCRnx while
counting up, and set on the compare match while downcounting. In inverting Compare Output
mode, the operation is inverted. The dual-slope operation gives a lower maximum operation fre-
quency compared to the single-slope operation. However, due to the symmetric feature of the
dual-slope P W M modes, these modes are preferred for motor control applications.
The main difference between the phase correct, and the phase and frequency correct P W M
mode is the time the OCRnx Register is updated by the OCRnx buffer Register, (see Figure 53
and Figure 54 ).
The P W M resolution for the phase and frequency correct P W M mode can be defined by either
ICRn or OCRnA. The minimum resolution allowed is 2-bit (ICRn or OCRnA set to 0x0003), and
the maximum resolution is 16-bit (ICRn or OCRnA set to MAX). The P W M resolution in bits can
be calculated using the following equation:
log ( 2 )
In phase and frequency correct P W M mode the counter is incremented until the counter value
matches either the value in ICRn ( W GMn3:0 = 8), or the value in OCRnA ( W GMn3:0 = 9). The
counter has then reached the TOP and changes the count direction. The TCNTn value will be
equal to TOP for one timer clock cycle. The timing diagram for the phase correct and frequency
correct P W M mode is shown on Figure 54 . The figure shows phase and frequency correct P W M
mode when OCRnA or ICRn is used to define TOP. The TCNTn value is in the timing diagram
shown as a histogram for illustrating the dual-slope operation. The diagram includes non-
inverted and inverted P W M outputs. The small horizontal line marks on the TCNTn slopes repre-
sent compare matches between OCRnx and TCNTn. The OCnx interrupt flag will be set when a
compare match occurs.
128
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