參數(shù)資料
型號: ST72371
廠商: 意法半導體
英文描述: 8-Bit MCUs with 16K ROM/OTP/EPROM, 512 Bytes RAM, ADC, DAC (PWM), Timer, IIC and SCI(8位微控制器(8M))
中文描述: 8 - 16K的光碟/雙層/存儲器,512字節(jié)RAM,ADC和DAC的器(PWM),定時器,IIC和脊髓損傷(8位微控制器(8米)位MCU)
文件頁數(shù): 41/94頁
文件大?。?/td> 642K
代理商: ST72371
41/94
ST72371/ST72372
16-BIT TIMER
(Cont’d)
4.3.3.7 Pulse Width Modulation Mode
Pulse Width Modulation mode enables the gener-
ation of a signal with a frequency and pulse length
determined by the value of the OC1R and OC2R
registers.
The pulse width modulation mode uses the com-
plete Output Compare 1 function plus the OC2R
register.
Procedure
To use pulse width modulation mode:
1. Load the OC2R register with the value corre-
sponding to the period of the signal.
2. Load the OC1R register with the value corre-
sponding to the length of the pulse if (OLVL1=0
and OLVL2=1).
3. Select the following in the CR1 register:
– Using the OLVL1 bit, select the level to be ap-
plied to the OCMP1 pin after a successful
comparison with OC1R register.
– Using the OLVL2 bit, select the level to be ap-
plied to the OCMP1 pin after a successful
comparison with OC2R register.
4. Select the following in the CR2 register:
– Set OC1E bit: the OCMP1 pin is then dedicat-
ed to the output compare 1 function.
– Set the PWM bit.
– Select the timer clock (CC1-CC0) (seeTable
1).
If OLVL1=1 and OLVL2=0 the length of the pulse
is the difference between the OC2R and OC1R
registers.
The OC
i
R register value required for a specific tim-
ing application can be calculated using the follow-
ing formula:
Where:
– t = Desired output compare period (seconds)
– f
CPU
= Internal clock frequency (see Miscella-
neous register)
t
PRESC
= Timer clock prescaler (CC1-CC0
bits , see Table 1)
The Output Compare 2 event causes the counter
to be initialized to FFFCh (SeeFigure 10).
Note:
After a write instruction to the OCiHR regis-
ter, the output compare function is inhibited until
the OCiLR register is also written.
The ICF1 bit is set by hardware when the counter
reaches the OC2R value and can produce a timer
interrupt if the ICIE bit is set and the I bitis cleared.
Therefore the Input Capture 1 function is inhibited
but the Input Capture 2 is available.
The OCF1 and OCF2 bits cannot be set by hard-
ware in PWM mode therefore the Output Compare
interrupt is inhibited.
When the Pulse Width Modulation (PWM) and
One Pulse Mode (OPM) bits are both set, the
PWM mode is the only active one.
Figure 26. Pulse Width Modulation Mode Timing
OCiR Value =
t
*
f
CPU
t
PRESC
- 5
Counter
= OC1R
OCMP1 = OLVL2
Counter is reset
to FFFCh
Counter
= OC2R
OCMP1 = OLVL1
When
When
Pulse Width Modulation cycle
ICF1 bit is set
COUNTER
34E2
FFFC FFFD FFFE
2ED0 2ED1 2ED2
34E2
FFFC
OLVL2
OLVL2
OLVL1
OCMP1
compare2
compare1
compare2
Note:
OC1R=2ED0h, OC2R=34E2, OLVL1=0, OLVL2= 1
相關PDF資料
PDF描述
ST72372 8-Bit MCUs with 16K ROM/OTP/EPROM, 512 Bytes RAM, ADC, DAC (PWM), Timer, IIC and SCI(8位微控制器(8M))
ST72681 USB 2.0 HIGH-SPEED 8-BIT MCU FLASH DRIVE CONTROLLER
ST72753L4 8-BIT MCU FOR MONITORS WITH UP TO 32K ROM, 1K RAM, ADC, TIMER, SYNC, PWM/BRM, DDC/DMA & I2C
ST72753L5 8-BIT MCU FOR MONITORS WITH UP TO 32K ROM, 1K RAM, ADC, TIMER, SYNC, PWM/BRM, DDC/DMA & I2C
ST72753L6 8-BIT MCU FOR MONITORS WITH UP TO 32K ROM, 1K RAM, ADC, TIMER, SYNC, PWM/BRM, DDC/DMA & I2C
相關代理商/技術參數(shù)
參數(shù)描述
ST72371N4B1 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:8-BIT MCUs WITH 16K ROM/OTP/EPROM,512 BYTES RAM, ADC, DAC (PWM), TIMER, I2C AND SCI
ST72371N4B1/XXX 制造商:未知廠家 制造商全稱:未知廠家 功能描述:MICROCONTROLLER|8-BIT|ST72 CPU|CMOS|SDIP|56PIN|PLASTIC
ST72371N4T1 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:8-BIT MCUs WITH 16K ROM/OTP/EPROM,512 BYTES RAM, ADC, DAC (PWM), TIMER, I2C AND SCI
ST72372 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:8-BIT MCUs WITH 16K ROM/OTP/EPROM,512 BYTES RAM, ADC, DAC (PWM), TIMER, I2C AND SCI
ST72372J4B1 制造商:STMICROELECTRONICS 制造商全稱:STMicroelectronics 功能描述:8-BIT MCUs WITH 16K ROM/OTP/EPROM,512 BYTES RAM, ADC, DAC (PWM), TIMER, I2C AND SCI