參數(shù)資料
型號: ST72651R4
英文描述: ST7 - LOW-POWER. FULL-SPEED USB 8-BIT MCU WITH 32K FLASH. 5K RAM. FLASH CARD I/F. TIMER. PWM. ADC. I2C
中文描述: ST7的-低功耗。全速USB 8位32K快閃微控制器。 5K內(nèi)存。閃存卡的I /樓計時器。脈寬調(diào)制。 ADC的。的I2C
文件頁數(shù): 161/166頁
文件大?。?/td> 2089K
代理商: ST72651R4
ST7265x
94/166
PWM/BRM GENERATOR (Cont’d)
BRM Generation
The BRM bits allow the addition of a pulse to wid-
en a standard PWM pulse for specific PWM cy-
cles. This has the effect of “fine-tuning” the PWM
Duty cycle (without modifying the base duty cycle),
thus, with the external filtering, providing additional
fine voltage steps.
The incremental pulses (with duration of TCPU) are
added to the beginning of the original PWM pulse.
The PWM intervals which are added to are speci-
fied in the 4-bit BRM register and are encoded as
shown in the following table. The BRM values
shown may be combined together to provide a
summation of the incremental pulse intervals
specified.
The pulse increment corresponds to the PWM res-
olution.
For example,if
– Data 18h is written to the PWM register
– Data 06h (00000110b) is written to the BRM reg-
ister
– with a 8MHz internal clock (125ns resolution)
Then 3.0
s-long pulse will be output at 8 s inter-
vals, except for cycles numbered 2,4,6,10,12,14,
where the pulse is broadened to 3.125
s.
Note. If 00h is written to both PWM and BRM reg-
isters, the generator output will remain at “0”. Con-
versely, if both registers hold data 3Fh and 0Fh,
respectively, the output will remain at “1” for all in-
tervals 1 to 15, but it will return to zero at interval 0
for an amount of time corresponding to the PWM
resolution (TCPU).
An output can be set to a continuous “1” level by
clearing the PWM and BRM values and setting
POL = “1” (inverted polarity) in the PWM register.
This allows a PWM/BRM channel to be used as an
additional I/O pin if the DAC function is not re-
quired.
Table 30. Bit BRM Added Pulse Intervals
(Interval #0 not selected).
Figure 55. BRM pulse addition (PWM > 0)
BRM 4 - Bit Data
Incremental Pulse Intervals
0000
none
0001
i = 8
0010
i = 4,12
0100
i = 2,6,10,14
1000
i = 1,3,5,7,9,11,13,15
T
CPU x 64
T
CPU x 64
T
CPU x 64
T
CPU x 64 increment
m = 1
m = 0
m = 2
T
CPU x 64
m = 15
相關(guān)PDF資料
PDF描述
ST72651R6 SODIMM MEMORY MODULE, 64MB, INDUSTRIAL TEMP
ST72651R6T1 ST7 - LOW-POWER. FULL-SPEED USB 8-BIT MCU WITH 32K FLASH. 5K RAM. FLASH CARD I/F. TIMER. PWM. ADC. I2C
ST72652R4T1 ST7 - LOW-POWER. FULL-SPEED USB 8-BIT MCU WITH 32K FLASH. 5K RAM. FLASH CARD I/F. TIMER. PWM. ADC. I2C
ST7271J1B1 8-BIT MICROCONTROLLER
ST7271N1B1 8-BIT MICROCONTROLLER
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
ST7265X-EVAL/MS 制造商:STMicroelectronics 功能描述:ST6 EVAL BD - Bulk
ST7265X-EVAL/PFD 制造商:STMicroelectronics 功能描述:USB FLASH EVAL - Bulk
ST7266 制造商:6940 功能描述:ST7266
ST7267C8T1L 制造商:STMicroelectronics 功能描述:
ST72681/R12 制造商:STMicroelectronics 功能描述:CONTROLLER FOR HIGH-PERFORMANCE BUS-POWERED USB 2.0 FLASH DR - Trays