PWM Library

PWM library

The General-Purpose Timer module is available with a number of ARM MCUs. mikroBasic PRO for ARM provides a library which simplifies using of the PWM mode of General-Purpose Timer Module.

Important :

PWM library routines require you to specify the module you want to use. To select the desired PWM module, simply change the letter x in the routine prototype for a number from 0 to 7.
Number of PWM modules differs from chip to chip. Please, read the appropriate datasheet before utilizing this library.
For Stellaris MCUs with dedicated PORT functions, prior to PWM module initialization, user must set appropriate pins as output. Please, see GPIO_Config routine.

PWM_CCPx_Init

Prototype

' for Stellaris MCUs with dedicated PORT functions :

sub function PWM_CCPx_Init(dim freq_hz as longword) as longword

' for Stellaris MCUs with alternative PORT functions on GPIO pins :

sub function PWM_CCPx_Init(dim freq_hz as longword, dim module as ^const Module_Struct) : longword

Description

Initializes the PWM module for Stellaris Cortex M3 MCUs.

Parameters

freq_hz: PWM frequency in Hz (refer to device datasheet for correct values in respect with Fosc).

module: appropriate module pinout, see the following table :

CCP Module Pinouts for Stellaris Cortex M3
CCP0	_GPIO_MODULE_CCP0_B0	_GPIO_MODULE_CCP0_B2	_GPIO_MODULE_CCP0_B5	_GPIO_MODULE_CCP0_C6	_GPIO_MODULE_CCP0_C7
	_GPIO_MODULE_CCP0_D3	_GPIO_MODULE_CCP0_D4	_GPIO_MODULE_CCP0_F4	_GPIO_MODULE_CCP0_J2	_GPIO_MODULE_CCP0_J7
CCP1	_GPIO_MODULE_CCP1_A6	_GPIO_MODULE_CCP1_B1	_GPIO_MODULE_CCP1_B6	_GPIO_MODULE_CCP1_C4	_GPIO_MODULE_CCP1_C5
	_GPIO_MODULE_CCP1_D7	_GPIO_MODULE_CCP1_E3	_GPIO_MODULE_CCP1_F6	_GPIO_MODULE_CCP1_J6
CCP2	_GPIO_MODULE_CCP2_B1	_GPIO_MODULE_CCP2_B5	_GPIO_MODULE_CCP2_C4	_GPIO_MODULE_CCP2_D1	_GPIO_MODULE_CCP2_D5	_GPIO_MODULE_CCP2_E1
	_GPIO_MODULE_CCP2_E2	_GPIO_MODULE_CCP2_E4	_GPIO_MODULE_CCP2_F5	_GPIO_MODULE_CCP2_J5
CCP3	_GPIO_MODULE_CCP3_A7	_GPIO_MODULE_CCP3_B2	_GPIO_MODULE_CCP3_C5	_GPIO_MODULE_CCP3_C6	_GPIO_MODULE_CCP3_D4	_GPIO_MODULE_CCP3_E0
	_GPIO_MODULE_CCP3_E4	_GPIO_MODULE_CCP3_F1	_GPIO_MODULE_CCP3_G4
CCP4	_GPIO_MODULE_CCP4_A7	_GPIO_MODULE_CCP4_C4	_GPIO_MODULE_CCP4_C7	_GPIO_MODULE_CCP4_D5	_GPIO_MODULE_CCP4_E2	_GPIO_MODULE_CCP4_F7	_GPIO_MODULE_CCP4_J4
CCP5	_GPIO_MODULE_CCP5_B5	_GPIO_MODULE_CCP5_B6	_GPIO_MODULE_CCP5_C4	_GPIO_MODULE_CCP5_D2	_GPIO_MODULE_CCP5_E5	_GPIO_MODULE_CCP5_G7	_GPIO_MODULE_CCP5_G5
CCP6	_GPIO_MODULE_CCP6_B5	_GPIO_MODULE_CCP6_D0	_GPIO_MODULE_CCP6_D2	_GPIO_MODULE_CCP6_E1	_GPIO_MODULE_CCP6_H0	_GPIO_MODULE_CCP6_J3
CCP7	_GPIO_MODULE_CCP7_B6	_GPIO_MODULE_CCP7_D1	_GPIO_MODULE_CCP7_D3	_GPIO_MODULE_CCP7_E3	_GPIO_MODULE_CCP7_H1

Returns

This function returns calculated timer period.

Requires

MCU must have the HW PWM Module.
Prior to PWM module initialization user must set appropriate pins as output. Please, see GPIO_Config routine.
PWM library routines require you to specify the module you want to use. To select the desired PWM module, simply change the letter x in the routine prototype for a number from 0 to 7.

Example

' for MCUs with dedicated PORT functions :
GPIO_Config(@GPIO_PORTD_DATA_BITS, _GPIO_PINMASK_4, _GPIO_DIR_NO_CHANGE, _GPIO_CFG_ADV_CCP)
ratio = PWM_CCP0_Init(25000)                          
PWM_CCP0_Set_Duty(ratio/4,_PWM_INVERTED_ENABLE)
PWM_CCP0_Start()

' for MCUs with alternative PORT functions on GPIO pins :
ratio = PWM_CCP0_Init(25000, @_GPIO_MODULE_CCP0_B5)                       
PWM_CCP0_Set_Duty(ratio/4,_PWM_INVERTED_ENABLE)
PWM_CCP0_Start()

Notes

Number of available PWM channels depends on MCU. Refer to MCU datasheet for details.

PWM_TnCCPx_Init

Prototype

sub function PWM_TnCCPx_Init(dim freq_hz as longword, dim module as ^const Module_Struct) : longword

Description

Initializes the PWM module for Stellaris Cortex M4 MCUs.

Parameters

freq_hz: PWM frequency in Hz (refer to device datasheet for correct values in respect with Fosc).

module: appropriate module pinout, see the following table :

CCP Module Pinouts for Stellaris Cortex M4
	CCP0	CCP1
Timer0	_GPIO_MODULE_T0CCP0_F0_AHB	_GPIO_MODULE_T0CCP1_F1_AHB
	_GPIO_MODULE_T0CCP0_B6_AHB	_GPIO_MODULE_T0CCP1_B7_AHB
	_GPIO_MODULE_T0CCP0_L0_AHB	_GPIO_MODULE_T0CCP1_L1_AHB
Timer1	_GPIO_MODULE_T1CCP0_B4_AHB	_GPIO_MODULE_T1CCP1_B5_AHB
	_GPIO_MODULE_T1CCP0_L2_AHB	_GPIO_MODULE_T1CCP1_F3_AHB
	_GPIO_MODULE_T1CCP0_F2_AHB	_GPIO_MODULE_T1CCP1_J1_AHB
	_GPIO_MODULE_T1CCP0_J0_AHB	_GPIO_MODULE_T1CCP1_L3_AHB
Timer2	_GPIO_MODULE_T2CCP0_B0_AHB	_GPIO_MODULE_T2CCP1_B1_AHB
	_GPIO_MODULE_T2CCP0_F4_AHB	_GPIO_MODULE_T2CCP1_F5_AHB
	_GPIO_MODULE_T2CCP0_J2_AHB	_GPIO_MODULE_T2CCP1_J3_AHB
	_GPIO_MODULE_T2CCP0_L4_AHB	_GPIO_MODULE_T2CCP1_L5_AHB
Timer3	_GPIO_MODULE_T3CCP0_B2_AHB	_GPIO_MODULE_T3CCP1_B3_AHB
	_GPIO_MODULE_T3CCP0_F6_AHB	_GPIO_MODULE_T3CCP1_F7_AHB
	_GPIO_MODULE_T3CCP0_J4_AHB	_GPIO_MODULE_T3CCP1_J5_AHB
	_GPIO_MODULE_T3CCP0_L6_AHB	_GPIO_MODULE_T3CCP1_L7_AHB
Timer4	_GPIO_MODULE_T4CCP0_C0_AHB	_GPIO_MODULE_T4CCP1_C1_AHB
	_GPIO_MODULE_T4CCP0_G0_AHB	_GPIO_MODULE_T4CCP1_G1_AHB
	_GPIO_MODULE_T4CCP0_M0_AHB	_GPIO_MODULE_T4CCP1_M1_AHB
	_GPIO_MODULE_T4CCP0_P0_AHB
Timer5	_GPIO_MODULE_T5CCP0_C2_AHB	_GPIO_MODULE_T5CCP1_C3_AHB
	_GPIO_MODULE_T5CCP0_G2_AHB	_GPIO_MODULE_T5CCP1_G3_AHB
	_GPIO_MODULE_T5CCP0_M2_AHB	_GPIO_MODULE_T5CCP1_M3_AHB
	_GPIO_MODULE_T5CCP0_P2_AHB

Returns

This function returns calculated timer period.

Requires

MCU must have the HW PWM Module.
Prior to PWM module initialization user must set appropriate pins as output. Please, see GPIO_Config routine.
PWM library routines require you to specify the module you want to use. To select the desired PWM module, simply change the letter x in the routine prototype for a number 0 or 1 to select desired PWM module and letter n from 0 to 5 depending on the used timer module.

Example

ratio = PWM_T0CCP0_Init(25000, @_GPIO_MODULE_T0CCP0_F0_AHB)             
PWM_PWM_T0CCP0_Set_Duty(ratio/4,_PWM_INVERTED_ENABLE)
PWM_PWM_T0CCP0_Start()

Notes Number of PWM and Timer modules differs from chip to chip. Please, read the appropriate datasheet before utilizing this library.

PWM_TIMn_Init

Prototype	function PWM_TIMn_Init(freq_hz : dword) : word;
Description	Initializes the Timer module in PWM mode for ST MCUs.
Parameters	`freq_hz:` PWM frequency in Hz (refer to device datasheet for correct values in respect with Fosc).
Returns	This function returns calculated timer period.
Requires	MCU must support the Timer module in PWM mode. PWM library routines require you to specify the Timer module you want to use. To select the desired Timer module, simply change the letter n in the routine prototype for a number from 0 to 17.
Example	ratio := PWM_TIM0_Init(25000); PWM_TIM0_Set_Duty(ratio/4,_PWM_INVERTED_ENABLE); PWM_TIM0_Start();
Notes	Number of Timer modules differs from chip to chip. Please, read the appropriate datasheet before utilizing this library.

PWM_CCPx_Set_Duty

Prototype

sub procedure PWM_CCPx_Set_Duty(dim duty as word, dim inverted as byte)

Description

The function changes PWM duty ratio for Stellaris Cortex M3 MCUs.

Parameters

duty: PWM duty ratio. Valid values: 0 to timer period returned by the PWM_CCPx_Init function.

inverted: inverted and non inverted PWM signals. Valid values :

Inverted parameter
Description	Predefined library const
`Inverted PWM signal`	`_PWM_INVERTED_ENABLE`
`Non-inverted PWM signal`	`_PWM_INVERTED_DISABLE`

Returns

Nothing.

Requires

MCU must have the HW PWM Module.
PWM module must be properly initialized. See PWM_CCPx_Init routine.
PWM library routines require you to specify the module you want to use. To select the desired PWM module, simply change the letter x in the routine prototype for a number from 0 to 7.

Example

' Set channel 1 duty ratio to 50%:
dim pwm_period1 as word
...
PWM_CCP0_Set_Duty(pwm_period1/2, 1)

Notes

Number of available PWM channels depends on MCU. Refer to MCU datasheet for details.

PWM_TnCCPx_Set_Duty

Prototype

sub procedure PWM_TnCCPx_Set_Duty(dim duty as word, dim inverted as byte)

Description

The function changes PWM duty ratio for Stellaris Cortex M4 MCUs.

Parameters

duty: PWM duty ratio. Valid values: 0 to timer period returned by the PWM_CCPx_Init function.

inverted: inverted and non inverted PWM signals. Valid values :

Inverted parameter
Description	Predefined library const
`Inverted PWM signal`	`_PWM_INVERTED_ENABLE`
`Non-inverted PWM signal`	`_PWM_INVERTED_DISABLE`

Returns

Nothing.

Requires

MCU must have the HW PWM Module.
Prior to PWM module initialization user must set appropriate pins as output. Please, see GPIO_Config routine.
PWM module must be properly initialized. See PWM_TnCCPx_Init routine.
PWM library routines require you to specify the module you want to use. To select the desired PWM module, simply change the letter x in the routine prototype for a number 0 or 1 to select desired PWM module and letter n from 0 to 5 depending on the used timer module.

Example

' Set channel 1 duty ratio to 50%:
dim pwm_period1 as word
...
PWM_T0CCP0_Set_Duty(pwm_period1/2, 1)

Notes Number of PWM and Timer modules differs from chip to chip. Please, read the appropriate datasheet before utilizing this library.

PWM_TIMn_Set_Duty

Prototype

procedure PWM_TIMn_Set_Duty(duty : word; inverted : byte; channel : byte);

Description

The function changes duty ratio for Timer module in PWM mode for ST MCUs.

Parameters

duty: PWM duty ratio. Valid values: 0 to timer period returned by the PWM_TIMn_Init function.

inverted: inverted and non inverted PWM signals. Valid values :

Inverted parameter
Description	Predefined library const
`Inverted PWM signal`	`_PWM_INVERTED`
`Non-inverted PWM signal`	`_PWM_NON_INVERTED`

channel: desired PWM channel :

Channel parameter
Description	Predefined library const
`Channel 1`	`_PWM_CHANNEL1`
`Channel 2`	`_PWM_CHANNEL2`
`Channel 3`	`_PWM_CHANNEL3`
`Channel 4`	`_PWM_CHANNEL4`

Returns

Nothing.

Requires

MCU must support the Timer module in PWM mode.
PWM mode must be properly initialized. See PWM_TIMn_Init routine.
PWM library routines require you to specify the Timer module you want to use. To select the desired Timer module, simply change the letter n in the routine prototype for a number from 0 to 17.

Example

// Set channel 1 duty ratio to 50%:
var pwm_period1 : word;
...
PWM_TIM0_Set_Duty(pwm_period1/2, _PWM_NON_INVERTED, _PWM_CHANNEL1);

Notes

Number of available Timer modules and PWM channels depends on MCU. Refer to MCU datasheet for details.

PWM_CCPx_Start

Prototype	sub procedure PWM_CCPx_Start()
Description	Starts appropriate PWM module for Stellaris Cortex M3 MCUs.
Parameters	None.
Returns	Nothing.
Requires	MCU must have the HW PWM Module. PWM channel must be properly initialized. See PWM_CCPx_Init routine. PWM library routines require you to specify the module you want to use. To select the desired PWM module, simply change the letter x in the routine prototype for a number from 0 to 7.
Example	' Start PWM module PWM_CCP0_Start()
Notes	Number of available PWM channels depends on MCU. Refer to MCU datasheet for details.

PWM_TnCCPx_Start

Prototype	sub procedure PWM_TnCCPx_Start()
Description	Starts appropriate PWM module for Stellaris Cortex M4 MCUs.
Parameters	None.
Returns	Nothing.
Requires	MCU must have the HW PWM Module. Prior to PWM module initialization user must set appropriate pins as output. Please, see GPIO_Config routine. PWM channel must be properly initialized. See PWM_TnCCPx_Init routine. PWM library routines require you to specify the module you want to use. To select the desired PWM module, simply change the letter x in the routine prototype for a number 0 or 1 to select desired PWM module and letter n from 0 to 5 depending on the used timer module.
Example	' Start PWM module PWM_T0CCP0_Start()
Notes	Number of PWM and Timer modules differs from chip to chip. Please, read the appropriate datasheet before utilizing this library.

PWM_TIMn_Start

Prototype

procedure PWM_TIMn_Start(channel : byte; module : ^const Module_Struct);

Description

Starts appropriate Timer module in PWM mode for ST MCUs.

Parameters

channel: desired PWM channel :

Channel parameter
Description	Predefined library const
`Channel 1`	`_PWM_CHANNEL1`
`Channel 2`	`_PWM_CHANNEL2`
`Channel 3`	`_PWM_CHANNEL3`
`Channel 4`	`_PWM_CHANNEL4`

module: appropriate module pinout, see the following table :

PWM Module Pinouts for ST
	Channel 1	Channel 2	Channel 3	Channel 4
Timer1	_GPIO_MODULE_TIM1_CH1_PA8	_GPIO_MODULE_TIM1_CH2_PA9	_GPIO_MODULE_TIM1_CH3_PA10	_GPIO_MODULE_TIM1_CH4_PA11
	_GPIO_MODULE_TIM1_CH1_PE9	_GPIO_MODULE_TIM1_CH2_PE11	_GPIO_MODULE_TIM1_CH3_PE13	_GPIO_MODULE_TIM1_CH4_PE14
Timer2	_GPIO_MODULE_TIM2_CH1_PA0	_GPIO_MODULE_TIM2_CH2_PA1	_GPIO_MODULE_TIM2_CH3_PA2	_GPIO_MODULE_TIM2_CH4_PA3
	_GPIO_MODULE_TIM2_CH1_PA5	_GPIO_MODULE_TIM2_CH2_PB3	_GPIO_MODULE_TIM2_CH3_PB10	_GPIO_MODULE_TIM2_CH4_PB11
Timer3	_GPIO_MODULE_TIM3_CH1_PA6	_GPIO_MODULE_TIM3_CH2_PA7	_GPIO_MODULE_TIM3_CH3_PB0	_GPIO_MODULE_TIM3_CH4_PB1
	_GPIO_MODULE_TIM3_CH1_PB4	_GPIO_MODULE_TIM3_CH2_PB5	_GPIO_MODULE_TIM3_CH3_PC8	_GPIO_MODULE_TIM3_CH4_PC9
	_GPIO_MODULE_TIM3_CH1_PC6	_GPIO_MODULE_TIM3_CH2_PC7
Timer4	_GPIO_MODULE_TIM4_CH1_PB6	_GPIO_MODULE_TIM4_CH2_PB7	_GPIO_MODULE_TIM4_CH3_PB8	_GPIO_MODULE_TIM4_CH4_PB9
	_GPIO_MODULE_TIM4_CH1_PD12	_GPIO_MODULE_TIM4_CH2_PD13	_GPIO_MODULE_TIM4_CH3_PD14	_GPIO_MODULE_TIM4_CH4_PD15
Timer5	_GPIO_MODULE_TIM5_CH1_PH10	_GPIO_MODULE_TIM5_CH2_PA1	_GPIO_MODULE_TIM5_CH3_PA2	_GPIO_MODULE_TIM5_CH4_PA3
		_GPIO_MODULE_TIM5_CH2_PH11	_GPIO_MODULE_TIM5_CH3_PH12	_GPIO_MODULE_TIM5_CH4_PI0
Timer8	_GPIO_MODULE_TIM8_CH1_PC6	_GPIO_MODULE_TIM8_CH2_PC7	_GPIO_MODULE_TIM8_CH3_PC8	_GPIO_MODULE_TIM8_CH4_PC9
	_GPIO_MODULE_TIM8_CH1_PI5	_GPIO_MODULE_TIM8_CH2_PI6	_GPIO_MODULE_TIM8_CH3_PI7	_GPIO_MODULE_TIM8_CH4_PI2
Timer9	_GPIO_MODULE_TIM9_CH1_PA2	_GPIO_MODULE_TIM9_CH2_PA3
	_GPIO_MODULE_TIM9_CH1_PE5	_GPIO_MODULE_TIM9_CH2_PE6
Timer10	_GPIO_MODULE_TIM10_CH1_PB8
	_GPIO_MODULE_TIM10_CH1_PF6
Timer11	_GPIO_MODULE_TIM11_CH1_PB9
	_GPIO_MODULE_TIM11_CH1_PF7
Timer12	_GPIO_MODULE_TIM12_CH1_PB14	_GPIO_MODULE_TIM12_CH2_PB15
	_GPIO_MODULE_TIM12_CH1_PH6	_GPIO_MODULE_TIM12_CH2_PH9
Timer13	_GPIO_MODULE_TIM13_CH1_PA6
	_GPIO_MODULE_TIM13_CH1_PF8
Timer14	_GPIO_MODULE_TIM14_CH1_PA7
	_GPIO_MODULE_TIM14_CH1_PF9
Timer15	_GPIO_MODULE_TIM15_CH1_PA2	_GPIO_MODULE_TIM15_CH2_PA3
	_GPIO_MODULE_TIM15_CH1_PB14	_GPIO_MODULE_TIM15_CH2_PB15
Timer16	_GPIO_MODULE_TIM16_CH1_PB8
	_GPIO_MODULE_TIM16_CH1_PA6
Timer17	_GPIO_MODULE_TIM17_CH1_PB9
	_GPIO_MODULE_TIM17_CH1_PA7

Returns

Nothing.

Requires

MCU must support the Timer module in PWM mode.
PWM mode must be properly initialized. See PWM_TIMn_Init routine.
PWM library routines require you to specify the Timer module you want to use. To select the desired Timer module, simply change the letter n in the routine prototype for a number from 0 to 17.

Example

// Start PWM module
PWM_TIM0_Start(_PWM_CHANNEL1, @_GPIO_MODULE_TIM1_CH1_PA8);

Notes

Number of available Timer modules and PWM channels depends on MCU. Refer to MCU datasheet for details.

PWM_CCPx_Stop

Prototype	sub procedure PWM_CCPx_Stop()
Description	Stops appropriate PWM module for Stellaris Cortex M3 MCUs.
Parameters	None.
Returns	Nothing.
Requires	MCU must have the HW PWM Module. PWM channel must be properly initialized. See PWM_CCPx_Init routine. PWM library routines require you to specify the module you want to use. To select the desired PWM module, simply change the letter x in the routine prototype for a number from 0 to 7.
Example	' Stop PWM module PWM_CCPx_Stop()
Notes	Number of PWM modules differs from chip to chip. Please, read the appropriate datasheet before utilizing this library.

PWM_TnCCPx_Stop

Prototype	sub procedure PWM_TnCCPx_Stop()
Description	Stops appropriate PWM module for Stellaris Cortex M4 MCUs.
Parameters	None.
Returns	Nothing.
Requires	MCU must have the HW PWM Module. Prior to PWM module initialization user must set appropriate pins as output. Please, see GPIO_Config routine. PWM channel must be properly initialized. See PWM_TnCCPx_Init routine. PWM library routines require you to specify the module you want to use. To select the desired PWM module, simply change the letter x in the routine prototype for a number 0 or 1 to select desired PWM module and letter n from 0 to 5 depending on the used timer module.
Example	' Stop PWM module PWM_T0CCP0_Stop()
Notes	Number of PWM and Timer modules differs from chip to chip. Please, read the appropriate datasheet before utilizing this library.

PWM_TIMn_Stop

Prototype

procedure PWM_TIMn_Stop(channel : byte);

Description

Stops appropriate Timer module in PWM mode for ST MCUs.

Parameters

channel: desired PWM channel :

Channel parameter
Description	Predefined library const
`Channel 1`	`_PWM_CHANNEL1`
`Channel 2`	`_PWM_CHANNEL2`
`Channel 3`	`_PWM_CHANNEL3`
`Channel 4`	`_PWM_CHANNEL4`

Returns

Nothing.

Requires

MCU must support the Timer module in PWM mode.
PWM mode must be properly initialized. See PWM_TIMn_Init routine.
PWM library routines require you to specify the Timer module you want to use. To select the desired Timer module, simply change the letter n in the routine prototype for a number from 0 to 17.

Example

// Start PWM module
PWM_TIM0_Stop(_PWM_CHANNEL1);

Notes

Number of available Timer modules and PWM channels depends on MCU. Refer to MCU datasheet for details.

Library Example

The example changes PWM duty ratio on channels 1 and 2 continuously. If LEDs are connected to channels 1 and 2, a gradual change of emitted light will be noticeable.

Stellaris

Copy Code To Clipboard

program Pwm_Demo
dim current_duty, old_duty, current_duty1, old_duty1 as word
    pwm_period1, pwm_period2 as word

sub procedure InitMain()
  GPIO_Digital_Input (@GPIO_PORTA, _GPIO_PINMASK_ALL) ' configure GPIO_PORTA pins as input
end sub

main:
  InitMain()
  current_duty  = 100                         ' initial value for current_duty
  current_duty1 = 100                         ' initial value for current_duty1

  pwm_period1 = PWM_CCP0_Init(5000, @_GPIO_MODULE_CCP0_B0)
  pwm_period2 = PWM_CCP3_Init(5000, @_GPIO_MODULE_CCP3_B2)

  PWM_CCP0_Start()
  PWM_CCP3_Start()

  PWM_CCP0_Set_Duty(current_duty,  _PWM_INVERTED_DISABLE)  ' Set current duty for PWM_CCP0
  PWM_CCP3_Set_Duty(current_duty1, _PWM_INVERTED_DISABLE)  ' Set current duty for PWM_CCP3

  while (TRUE)                               ' endless loop
    if GPIO_PORTA_DATA.B0 = 1 then           ' button on RA0 pressed
      Delay_ms(1)
      current_duty = current_duty + 5        ' increment current_duty
      if (current_duty > pwm_period1) then   ' if we increase current_duty greater then possible pwm_period1 value
        current_duty = 0                     ' reset current_duty value to zero
      end if
      PWM_CCP0_Set_Duty(current_duty,  _PWM_INVERTED_DISABLE) ' set newly acquired duty ratio
    end if

    if GPIO_PORTA_DATA.B1 = 1 then           ' button on RA1 pressed
      Delay_ms(1)
      current_duty = current_duty - 5        ' decrement current_duty
      if (current_duty > pwm_period1) then   ' if we decrease current_duty greater then possible pwm_period1 value (overflow)
        current_duty = pwm_period1           ' set current_duty to max possible value
      end if
      PWM_CCP0_Set_Duty(current_duty,  _PWM_INVERTED_DISABLE) ' set newly acquired duty ratio
    end if

    if GPIO_PORTA_DATA.B2 = 1 then           ' button on RA2 pressed
      Delay_ms(1)
      current_duty1 = current_duty1 + 5      ' increment current_duty1
      if (current_duty1 > pwm_period2) then  ' if we increase current_duty1 greater then possible pwm_period2 value
        current_duty1 = 0                    ' reset current_duty1 value to zero
      end if
      PWM_CCP3_Set_Duty(current_duty1, _PWM_INVERTED_DISABLE)       ' set newly acquired duty ratio
    end if

    if GPIO_PORTA_DATA.B3 = 1 then           ' button on RA3 pressed
      Delay_ms(1)
      current_duty1 = current_duty1 - 5      ' decrement current_duty1
      if (current_duty1 > pwm_period2) then  ' if we decrease current_duty1 greater then possible pwm_period1 value (overflow)
        current_duty1 = pwm_period2          ' set current_duty to max possible value
      end if
      PWM_CCP3_Set_Duty(current_duty1, _PWM_INVERTED_DISABLE)
    end if

    Delay_ms(1)                              ' slow down change pace a little
  wend
end.

STM32

Copy Code To Clipboard

program Pwm_Demo
dim current_duty, old_duty, current_duty1, old_duty1 as word
    pwm_period1, pwm_period2 as word

sub procedure InitMain()
  GPIO_Digital_Input (@GPIOA_BASE, _GPIO_PINMASK_3 or _GPIO_PINMASK_4 or _GPIO_PINMASK_5 or _GPIO_PINMASK_6) ' configure PORTA pins as input
end sub

main:
  InitMain()
  current_duty  = 100                         ' initial value for current_duty
  current_duty1 = 100                         ' initial value for current_duty1

  pwm_period1 = PWM_TIM1_Init(5000)
  pwm_period2 = PWM_TIM4_Init(5000)

  PWM_TIM1_Set_Duty(current_duty,  _PWM_NON_INVERTED, _PWM_CHANNEL1)  ' Set current duty for PWM_TIM1
  PWM_TIM4_Set_Duty(current_duty1, _PWM_NON_INVERTED, _PWM_CHANNEL2)  ' Set current duty for PWM_TIM4

  PWM_TIM1_Start(_PWM_CHANNEL1, @_GPIO_MODULE_TIM1_CH1_PE9)
  PWM_TIM4_Start(_PWM_CHANNEL2, @_GPIO_MODULE_TIM4_CH2_PD13)

  while (TRUE)                               ' endless loop
    if GPIOA_IDR.B3 = 1 then           ' button on RA3 pressed
      Delay_ms(1)
      current_duty = current_duty + 5        ' increment current_duty
      if (current_duty > pwm_period1) then   ' if we increase current_duty greater then possible pwm_period1 value
        current_duty = 0                     ' reset current_duty value to zero
      end if
      PWM_TIM1_Set_Duty(current_duty,  _PWM_NON_INVERTED, _PWM_CHANNEL1) ' set newly acquired duty ratio
    end if

    if GPIOA_IDR.B4 = 1 then           ' button on RA4 pressed
      Delay_ms(1)
      current_duty = current_duty - 5        ' decrement current_duty
      if (current_duty > pwm_period1) then   ' if we decrease current_duty greater then possible pwm_period1 value (overflow)
        current_duty = pwm_period1           ' set current_duty to max possible value
      end if
      PWM_TIM1_Set_Duty(current_duty,  _PWM_NON_INVERTED, _PWM_CHANNEL1) ' set newly acquired duty ratio
    end if

    if GPIOA_IDR.B5 = 1 then           ' button on RA5 pressed
      Delay_ms(1)
      current_duty1 = current_duty1 + 5      ' increment current_duty1
      if (current_duty1 > pwm_period2) then  ' if we increase current_duty1 greater then possible pwm_period2 value
        current_duty1 = 0                    ' reset current_duty1 value to zero
      end if
      PWM_TIM4_Set_Duty(current_duty1, _PWM_NON_INVERTED, _PWM_CHANNEL2)       ' set newly acquired duty ratio
    end if

    if GPIOA_IDR.B6 = 1 then           ' button on RA6 pressed
      Delay_ms(1)
      current_duty1 = current_duty1 - 5      ' decrement current_duty1
      if (current_duty1 > pwm_period2) then  ' if we decrease current_duty1 greater then possible pwm_period1 value (overflow)
        current_duty1 = pwm_period2          ' set current_duty to max possible value
      end if
      PWM_TIM4_Set_Duty(current_duty1, _PWM_NON_INVERTED, _PWM_CHANNEL2)
    end if

    Delay_ms(1)                              ' slow down change pace a little
  wend
end.

Want more examples and libraries?
Find them on

PWM library

Library Routines for Stellaris Cortex M3

Library Routines for Stellaris Cortex M4

Library Routines for ST

PWM_CCPx_Init

PWM_TnCCPx_Init

PWM_TIMn_Init

PWM_CCPx_Set_Duty

PWM_TnCCPx_Set_Duty

PWM_TIMn_Set_Duty

PWM_CCPx_Start

PWM_TnCCPx_Start

PWM_TIMn_Start

PWM_CCPx_Stop

PWM_TnCCPx_Stop

PWM_TIMn_Stop

Library Example

Stellaris

STM32