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PIC16F1827T-E/SS 数据手册 - Microchip（微芯）
制造商:
Microchip（微芯）
封装:
SSOP-20
描述:
18 /20/ 28引脚闪存单片机采用纳瓦XLP技术 18/20/28-Pin Flash Microcontrollers with nanoWatt XLP Technology
Pictures:
3D模型
符号图
焊盘图
引脚图
产品图
页面导航:
引脚图在P6P11P12P13P14P131P204P206P213P322Hot
典型应用电路图在P137P323
原理图在P10P16P52P63P73P97P131P135P139P154P158P164
封装尺寸在P384
标记信息在P383
封装信息在P383P385P386P390P391
功能描述在P315
技术参数、封装参数在P54P58P84P98P102P135P140P146P150P153P167P168
应用领域在P47P54P55P215P222
电气规格在P54P58P84P98P135P140P146P150P153P167P169P175
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PIC16F1827T-E/SS数据手册
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2011 Microchip Technology Inc. DS41391D-page 209
PIC16(L)F1826/27
24.3.2 SETUP FOR PWM OPERATION
The following steps should be taken when configuring
the CCP module for standard PWM operation:
1. Disable the CCPx pin output driver by setting the
associated TRIS bit.
2. Load the PRx register with the PWM period
value.
3. Configure the CCP module for the PWM mode
by loading the CCPxCON register with the
appropriate values.
4. Load the CCPRxL register and the DCxBx bits
of the CCPxCON register, with the PWM duty
cycle value.
5. Configure and start Timer2/4/6:
•Select the Timer2/4/6 resource to be used
for PWM generation by setting the
CxTSEL<1:0> bits in the CCPTMRS
register.
•Clear the TMRxIF interrupt flag bit of the
PIRx register. See Note below.
•Configure the TxCKPS bits of the TxCON
register with the Timer prescale value.
•Enable the Timer by setting the TMRxON bit
of the TxCON register.
6. Enable PWM output pin:
•Wait until the Timer overflows and the TMRxIF
bit of the PIRx register is set. See Note
below.
•Enable the CCPx pin output driver by clearing
the associated TRIS bit.
24.3.3 TIMER2/4/6 TIMER RESOURCE
The PWM standard mode makes use of one of the 8-bit
Timer2/4/6 timer resources to specify the PWM period.
Configuring the CxTSEL<1:0> bits in the CCPTMRS
register selects which Timer2/4/6 timer is used.
24.3.4 PWM PERIOD
The PWM period is specified by the PRx register of
Timer2/4/6. The PWM period can be calculated using
the formula of Equation 24-1.
EQUATION 24-1: PWM PERIOD
When TMRx is equal to PRx, the following three events
occur on the next increment cycle:
• TMRx is cleared
• The CCPx pin is set. (Exception: If the PWM duty
cycle = 0%, the pin will not be set.)
• The PWM duty cycle is latched from CCPRxL into
CCPRxH.
24.3.5 PWM DUTY CYCLE
The PWM duty cycle is specified by writing a 10-bit
value to multiple registers: CCPRxL register and
DCxB<1:0> bits of the CCPxCON register. The
CCPRxL contains the eight MSbs and the DCxB<1:0>
bits of the CCPxCON register contain the two LSbs.
CCPRxL and DCxB<1:0> bits of the CCPxCON
register can be written to at any time. The duty cycle
value is not latched into CCPRxH until after the period
completes (i.e., a match between PRx and TMRx
registers occurs). While using the PWM, the CCPRxH
register is read-only.
Equation 24-2 is used to calculate the PWM pulse
width.
Equation 24-3 is used to calculate the PWM duty cycle
ratio.
EQUATION 24-2: PULSE WIDTH
EQUATION 24-3: DUTY CYCLE RATIO
The CCPRxH register and a 2-bit internal latch are
used to double buffer the PWM duty cycle. This double
buffering is essential for glitchless PWM operation.
The 8-bit timer TMRx register is concatenated with either
the 2-bit internal system clock (F
OSC), or 2 bits of the
prescaler, to create the 10-bit time base. The system
clock is used if the Timer2/4/6 prescaler is set to 1:1.
When the 10-bit time base matches the CCPRxH and
2-bit latch, then the CCPx pin is cleared (see
Figure 24-4).
Note: In order to send a complete duty cycle and
period on the first PWM output, the above
steps must be included in the setup
sequence. If it is not critical to start with a
complete PWM signal on the first output,
then step 6 may be ignored.
PWM Period PRx1+4TOSC =
(TMRx Prescale Value)
Note 1: T
OSC = 1/FOSC
Note: The Timer postscaler (see Section 22.1
“Timer2/4/6 Operation”) is not used in the
determination of the PWM frequency.
Pulse Width CCPRxL:CCPxCON<5:4>
=
TOSC
(TMRx Prescale Value)
Duty Cycle Ratio
CCPRxL:CCPxCON<5:4>
4 PRx 1+
-----------------------------------------------------------------------=
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