Setting PWM Output

[daryl2]

Posted on March 09, 2008 at 23:44

Setting PWM Output

[daryl2]

Posted on March 07, 2008 at 06:54

Hi,

I am trying to generate PWM output using the STR750 MCU. Below are my settings. Somehow I am not able to get any PWM signals out. Anyone has any idea why this is so? Please enlighten me. Thank you very much // PWM, TIM0, TIM1 and TIM2 clock has been enabled PWM_InitTypeDef PWM_InitStructure; /* Configure P1.06 as alternate function (PWM_OC2) */ GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; GPIO_InitStructure.GPIO_Pin = GPIO_Pin_6; GPIO_Init(GPIO1, &GPIO_InitStructure); // PWM configuration PWM_InitStructure.PWM_Mode = PWM_Mode_PWM; PWM_InitStructure.PWM_Prescaler = 0x00; // TIM_CLK: 60 MHz PWM_InitStructure.PWM_CounterMode = PWM_CounterMode_Up; PWM_InitStructure.PWM_Period = 0x7530; // PWM frequency : ~2KHz PWM_InitStructure.PWM_Channel = PWM_Channel_2; PWM_InitStructure.PWM_Pulse2 = 0x3A98; // Duty cycle: 50% PWM_InitStructure.PWM_Polarity2 = PWM_Polarity2_Low; PWM_InitStructure.PWM_Polarity2N = PWM_Polarity2_Low; PWM_InitStructure.PWM_Complementary = PWM_Complementary_Disable; PWM_InitStructure.PWM_OCState = PWM_OCState_Disable; PWM_InitStructure.PWM_OCNState = PWM_OCNState_Enable; PWM_InitStructure.PWM_DeadTime = 0; PWM_Init(&PWM_InitStructure); PWM_Cmd(ENABLE);

[jpeacock2]

Posted on March 07, 2008 at 13:03

Do you have the PWM peripheral clock enabled?

MRCC_PeripheralClockConfig(MRCC_Peripheral_PWM, ENABLE); This is how I use the PWM channels:

Code:

/* PWM is configured to generate a 3Khz pulse with CK_TIM = 60MHz: * update frequency = CK_TIM/(Prescaler+1)(Period+1) = 300 Hz * The blower motor(s) require a PWM signal with a frequency of 150hz to 400hz. * A 100% duty cycle is on full, while a 0% duty cycle is completely off. */ PWM_DeInit(); /* reset PWM */ /* Configure blowers as PWM* outputs */ GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; GPIO_InitStructure.GPIO_Pin = GPIO_Pin_4 | GPIO_Pin_6 | GPIO_Pin_8; GPIO_Init(GPIO1, &GPIO_InitStructure); /* blower motors */ MRCC_PeripheralClockConfig(MRCC_Peripheral_PWM, ENABLE); /* PWM clock source enable */ /* PWM Channel 1 configuration: main ball blower */ PWM_InitStructure.PWM_Mode = PWM_Mode_PWM; PWM_InitStructure.PWM_Prescaler = 19999; // prescale by 60Mhz/20000 = 3Khz PWM_InitStructure.PWM_CounterMode = PWM_CounterMode_Up; PWM_InitStructure.PWM_Period = BLO_OFF - 1; // divide 3Khz /10 = 300Hz PWM_InitStructure.PWM_Complementary = PWM_Complementary_Enable; // enable inverted output pins PWM_InitStructure.PWM_Channel = PWM_Channel_1; PWM_InitStructure.PWM_Pulse1 = BLO_OFF; // startup motor off PWM_InitStructure.PWM_DTRAccess = PWM_DTRAccess_Disable; PWM_InitStructure.PWM_Polarity1N = PWM_Polarity1N_Low; // PWM1N active lo (invert to FET) PWM_InitStructure.PWM_RepetitionCounter = 0x05; PWM_Init(&PWM_InitStructure); /* PWM Channel 2 configuration: eject ball blower */ PWM_InitStructure.PWM_Channel = PWM_Channel_2; PWM_InitStructure.PWM_Pulse2 = BLO_OFF; // startup motor off PWM_InitStructure.PWM_Polarity2N = PWM_Polarity2N_Low; // PWM2N active lo PWM_Init(&PWM_InitStructure); /* PWM Channel 3 configuration: unused */ PWM_InitStructure.PWM_Channel = PWM_Channel_3; PWM_InitStructure.PWM_Pulse3 = BLO_OFF; // startup motor off PWM_InitStructure.PWM_Polarity3N = PWM_Polarity3N_Low; // PWM3N active lo // no dead time, no emergency stop PWM_InitStructure.PWM_DTRAccess = PWM_DTRAccess_Enable; PWM_InitStructure.PWM_Emergency = PWM_Emergency_Disable; PWM_InitStructure.PWM_DeadTime = 0x00; PWM_InitStructure.PWM_LOCKLevel = PWM_LOCKLevel_3; PWM_InitStructure.PWM_OSSIState = PWM_OSSIState_Enable; PWM_Init(&PWM_InitStructure); /* Enable PWM Main Outputs */ PWM_CtrlPWMOutputs(ENABLE); /* Enable PWM counter */ PWM_Cmd(ENABLE); To set the duty cycle takes one line: PWM_SetPulse(PWM_Channel_1, value0to99);

[daryl2]

Posted on March 09, 2008 at 23:44

thanks jakbird. Managed to solve my problem. My code did not run PWM_CtrlPWMOutputs(ENABLE).