參數PWM設置在PIC24FJ64GA002

Question

我工作的項目，我需要顯示不同的顏色上的RGB領導。我使用pwm在LED上驅動不同的顏色。我的PIC是PIC24FJ64GA004，現在我正在使用它。這個項目的基本概念是使用開關來控制顏色。在RGB

顏色的LED將根據今年天，一個月可以。爲此，我使用帶切換功能的7段數字計算日期和月份。

問題此刻正下面的代碼。我正在嘗試通過以下設置更改PWM值。但不是改變它，它給我一些奇怪的東西。 我需要你的幫助。你能幫我解決這個問題嗎？

for(counter=0x0000;counter<=0x4571;counter++){ 
//*****Timer2 starting from here*****// 
PR2     = 0x4571; // Initialize PR2 with 0x4571 = 17777 as PWM cycle 
IFS0bits.T2IF  = 0;  // Clear Output Compare interrupt flag 
IEC0bits.T2IE  = 1;  // Enable Output Compare interrupts 
T2CONbits.TON  = 1;  // Start Timer2 with assumed settings 
//**********************************// 
//*****For RED LED OC1 choosed with timer 2*****// 
OC1CONbits.OCM  = 0;  // Output compare channel is disabled 
OC1R    = 0x0000 ; // Initialize Compare Register1 with 50% duty cycle 
OC1RS    = counter; // Initialize Secondary Compare Register1 with 50% duty cycle 
OC1CONbits.OCSIDL = 0;  // Output capture will continue to operate in CPU Idle mode 
OC1CONbits.OCFLT = 0;  // No PWM Fault condition has occurred (this bit is only used when OCM<2:0> = 111) 
OC1CONbits.OCTSEL = 0;  // Timer2 is the clock source for output Compare 
OC1CONbits.OCM  = 0x6;  // PWM mode on OC, Fault pin disabled 

//*****For Green Led OC2 and OC3 Choosed with timer2 as well*****// 

OC2CONbits.OCM  = 0;  // Output compare channel is disabled 
OC2R    =0x0000;  // Initialize Compare Register1 with 50% duty cycle 
OC2RS    =counter; // Initialize Secondary Compare Register1 with 50% duty cycle 
OC2CONbits.OCSIDL = 0;  // Output capture will continue to operate in CPU Idle mode 
OC2CONbits.OCFLT = 0;  // No PWM Fault condition has occurred (this bit is only used when OCM<2:0> = 111) 
OC2CONbits.OCTSEL = 0;  // Timer2 is the clock source for output Compare 
OC2CONbits.OCM  = 0x6;  // PWM mode on OC, Fault pin disabled 


//*****For Blue Led OC2 and OC3 Choosed with timer2 as well*****// 
OC3CONbits.OCM  = 0;  // Output compare channel is disabled 
OC3R    = 0x0000;   // Initialize Compare Register1 with 50% duty cycle 
OC3RS    = counter; // Initialize Secondary Compare Register1 with 50% duty cycle 
OC3CONbits.OCSIDL = 0;  // Output capture will continue to operate in CPU Idle mode 
OC3CONbits.OCFLT = 0;  // No PWM Fault condition has occurred (this bit is only used when OCM<2:0> = 111) 
OC3CONbits.OCTSEL = 0;  // Timer2 is the clock source for output Compare 
OC3CONbits.OCM  = 0x6;  // PWM mode on OC, Fault pin disabled 

    } 

但此代碼的工作好了。我也提出了不同的價值觀。它工作正常。

//*****For RED LED OC1 choosed with timer 2*****// 
OC1CONbits.OCM  = 0;  // Output compare channel is disabled 
OC1R    = 0x22B8; // Initialize Compare Register1 with 50% duty cycle 
OC1RS    = 0x22B8; // Initialize Secondary Compare Register1 with 50% duty cycle 
OC1CONbits.OCSIDL = 0;  // Output capture will continue to operate in CPU Idle mode 
OC1CONbits.OCFLT = 0;  // No PWM Fault condition has occurred (this bit is only used when OCM<2:0> = 111) 
OC1CONbits.OCTSEL = 0;  // Timer2 is the clock source for output Compare 
OC1CONbits.OCM  = 0x6;  // PWM mode on OC, Fault pin disabled 

//*****For Green Led OC2 and OC3 Choosed with timer2 as well*****// 

OC2CONbits.OCM  = 0;  // Output compare channel is disabled 
OC2R    =0x22B8; // Initialize Compare Register1 with 50% duty cycle 
OC2RS    =0x22B8;//0x22B8; // Initialize Secondary Compare Register1 with 50% duty cycle 
OC2CONbits.OCSIDL = 0;  // Output capture will continue to operate in CPU Idle mode 
OC2CONbits.OCFLT = 0;  // No PWM Fault condition has occurred (this bit is only used when OCM<2:0> = 111) 
OC2CONbits.OCTSEL = 0;  // Timer2 is the clock source for output Compare 
OC2CONbits.OCM  = 0x6;  // PWM mode on OC, Fault pin disabled 


//*****For Blue Led OC2 and OC3 Choosed with timer2 as well*****// 
OC3CONbits.OCM  = 0;  // Output compare channel is disabled 
OC3R    = 0x22B8; // Initialize Compare Register1 with 50% duty cycle 
OC3RS    = 0x22B8; // Initialize Secondary Compare Register1 with 50% duty cycle 
OC3CONbits.OCSIDL = 0;  // Output capture will continue to operate in CPU Idle mode 
OC3CONbits.OCFLT = 0;  // No PWM Fault condition has occurred (this bit is only used when OCM<2:0> = 111) 
OC3CONbits.OCTSEL = 0;  // Timer2 is the clock source for output Compare 
OC3CONbits.OCM  = 0x6;  // PWM mode on OC, Fault pin disabled 

//*****Timer1 starting from here*****// 
PR1     = 65535; // Initialize PR2 cycle 
T1CONbits.TCKPS  = 2;  // Setting pre-scaler to 1/64 
IFS0bits.T1IF  = 0;  // Clear Output Compare interrupt flag 
IEC0bits.T1IE  = 1;  // Enable Output Compare interrupts 
T1CONbits.TON  = 1;  // Start Timer1 with assumed settings 
//*****Timer2 starting from here*****// 
PR2     = 0x4571; // Initialize PR2 with 0x4571 = 17777 as PWM cycle 
IFS0bits.T2IF  = 0;  // Clear Output Compare interrupt flag 
IEC0bits.T2IE  = 1;  // Enable Output Compare interrupts 
T2CONbits.TON  = 1;  // Start Timer2 with assumed settings 
//**********************************// 

Answer 1

您每次都在更新PWM週期。

這是非常不可能的櫃檯有時間到期，因此，你不斷進行復位它有機會去「做」一個PWM週期之前。

在循環結束後，你需要等待（至少一個）您的PWM已經過期。

的另一種方式可能是建立在你的循環希望下一個值，並有一箇中斷服務程序拷貝到PWM寄存器時，計時器到期。發生這種情況後，您可以設置下一個值:)您需要注意如何在主循環和ISR之間傳輸值，因爲它們實際上是不同的「線程」上下文。