參數(shù)資料
型號(hào): MC68HC05BD7P
廠商: MOTOROLA INC
元件分類: 微控制器/微處理器
英文描述: 8-BIT, MROM, 2.1 MHz, MICROCONTROLLER, PDIP40
封裝: DIP-40
文件頁數(shù): 42/85頁
文件大?。?/td> 302K
代理商: MC68HC05BD7P
SECTION 8: PULSE WIDTH MODULATION
MOTOROLA
Page 37
MC68HC05BD7 Rev. 2.0
GENERAL RELEASE SPECIFICATION
PRELIMINARY
SECTION 8
PULSE WIDTH MODULATION
There are 16 PWM channels. Channel 0 to channel 7 are dedicated PWM channels with
5V open-drain option. Channel 8 to channel 15 are shared with ports C under the control
of the corresponding configuration register. The channel 8 and channel 9 are 12V open-
drain outputs.
8.1
Operation of 8-Bit PWM
Each 8-Bit PWM channel is composed of an 8-bit register which contains a 5-bit PWM in
MSB portion and a 3-bit binary rate multiplier (BRM) in LSB portion. There are 16 data
registers as shown in Figure 8-1 located from $20 to $2F. The value programmed in the 5-
bit PWM portion will determine the pulse length of the output. The clock to the 5-bit PWM
portion is the MCU clock and the repetition rate of the output is hence 62.5 KHz at 2 MHz
MCU clock.
The 3-bit BRM will generate a number of narrow pulses which are equally distributed
among an 8-PWM-cycle frame. The number of pulses generated is equal to the number
programmed in the 3-bit BRM portion. An example of the waveform is shown in Figure 8-2.
Combining the 5-bit PWM together with the 3-bit BRM, the average duty cycle at the output
will be (M+N/8)/32, where M is the content of the 5-bit PWM portion, and N is the content
of the 3-bit BRM portion. Using this mechanism, a true 8-bit resolution PWM type DAC with
reasonably high repetition rate can be obtained.
Figure 8-1: PWM Data Register
The value of each PWM Data Register is continuously compared with the content of an
internal counter to determine the state of each PWM channel output pin. Double buffering
is not used in this PWM design.
0PWM3
0PWM1
0PWM4
0
7
0BRM1
0BRM2
0PWM0
0000000
6543210
0PWM2
W
R
PWMR
$20-$2F
reset
0BRM0
相關(guān)PDF資料
PDF描述
MC68HC705BD7B 8-BIT, OTPROM, 2.1 MHz, MICROCONTROLLER, PDIP42
MC68HC05C0B 8-BIT, 4 MHz, MICROCONTROLLER, PDIP42
MC68HC05C0P 8-BIT, 4 MHz, MICROCONTROLLER, PDIP40
MC68HC05C0FN 8-BIT, 4 MHz, MICROCONTROLLER, PQCC44
MC68HC05C12AFN 8-BIT, MROM, 2.1 MHz, MICROCONTROLLER, PQCC44
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MC68HC05C0CP 制造商:Motorola Inc 功能描述:
MC68HC05C12 制造商:FREESCALE 制造商全稱:Freescale Semiconductor, Inc 功能描述:HCMOS MICROCONTROLLER UNITS
MC68HC05C12B 制造商:FREESCALE 制造商全稱:Freescale Semiconductor, Inc 功能描述:HCMOS MICROCONTROLLER UNITS
MC68HC05C12CP 制造商:FREESCALE 制造商全稱:Freescale Semiconductor, Inc 功能描述:HCMOS MICROCONTROLLER UNITS
MC68HC05C12P 制造商:FREESCALE 制造商全稱:Freescale Semiconductor, Inc 功能描述:HCMOS MICROCONTROLLER UNITS