Interface to the PWM peripheral. More...

Functions
int	pwm_init ()
	Initializes this peripheral interface, to use before any other function in this file. More...

int	pwm_isInit ()
	true if pwm_init has been called with success

int	pwm_resetChannel (int channel)
	Resets the specified channel to: disabled, pwm mode, don't repeat last, silence=0, normal polarity, don't use fifo, don't use M/S Warning: the pwm peripheral likes to ignore the CTL_RPTL1_MASK and repeat the last word even if you say it not to. More...

int	pwm_clearFifo ()
	clears the fifo More...

int	pwm_setEnable (int channel, unsigned int value)
	Sets the enabled status of the specified channel. After the dma completes a transfer (a chain of control blocks) and 0 gets loaded as control block this is resetted to 0. More...

int	pwm_setMode (int channel, unsigned int mode)
	Sets the mode of the specified channel to PWM or Serializer. More...

int	pwm_setMSenable (int channel, unsigned int mode)
	Sets the pwm mode: M/S or the algorithm (see datasheet pag 139) More...

int	pwm_setRange (int channel, uint32_t range)
	Sets the range of the specified channel counter. More...

int	pwm_setData (int channel, uint32_t data)
	Sets the data for the specified channel: in Serializer mode (if not using fifo) it will be sent as pulses, in PWM mode it's the number of pulses in a period. More...

int	pwm_setClock (int clkSrc, int divisorInt, int divisorFrac)
	sets the clock divisor for the pwm (the base frequency is 19.2 MHz) More...

int	pwm_writeToFifo (unsigned int data)
	Write the provided data word to the fifo. More...

int	pwm_setDreqThreshold (unsigned int threshold)
	Sets the threshold under which the dreq signal is raised. More...

int	pwm_setSerializerMode (int channel, unsigned int mode)
	Set the serialized mode to use the fifo or the data register. More...

int	pwm_setDmaEnable (unsigned int value)
	Enables or disables the generation of the dma signals DREQ and PANIC. More...

int	pwm_setRepeatLastWord (int channel, unsigned int value)
	Sets the repetition of the last word in the fifo on serializer mode Warning: the pwm peripheral likes to ignore this setting and repeat the last word even if you say it not to. More...

Detailed Description

Interface to the PWM peripheral.

This peripheral is able to generate PWM signals. It has 3 modes:

Serializer mode: it seriallly outputs the bits of 32bit words, you can set the input to the data register or the fifo
M/S PWM: it outputs a pwm signal generated this way: it increments ciclically a counter, while it's lower to the setted threshold the output is high, while higher it's low
not-M/S PWM: it mantains the same duty cycle as M/S but it spreads the high part in little pulses See documentation at "BCM2835 ARM peripherals" pag 138

Function Documentation

int pwm_clearFifo ( )

clears the fifo

Returns: negative in case of error

int pwm_init ( )

Initializes this peripheral interface, to use before any other function in this file.

Returns: negative in case of error

int pwm_resetChannel ( int channel )

Resets the specified channel to: disabled, pwm mode, don't repeat last, silence=0, normal polarity, don't use fifo, don't use M/S Warning: the pwm peripheral likes to ignore the CTL_RPTL1_MASK and repeat the last word even if you say it not to.

Parameters

channel The channel

Returns: negative in case of error

int pwm_setClock	(	int	clkSrc,
		int	divisorInt,
		int	divisorFrac
	)

sets the clock divisor for the pwm (the base frequency is 19.2 MHz)

Parameters

clkSrc	Clock source, see the macros in clockManager. Normally you want CLK_SRC_OSCILLATOR (19.2MHz)
divisorInt	Integer part of the divisor
divisorFrac	Fractional part of the divisor

int pwm_setData	(	int	channel,
		uint32_t	data
	)

Sets the data for the specified channel: in Serializer mode (if not using fifo) it will be sent as pulses, in PWM mode it's the number of pulses in a period.

Parameters

channel	The channel: 1 or 2
data	The data value

Returns: negative in case of error

int pwm_setDmaEnable ( unsigned int value )

Enables or disables the generation of the dma signals DREQ and PANIC.

Parameters

value 0=disabled, any other value=enabled

int pwm_setDreqThreshold ( unsigned int threshold )

Sets the threshold under which the dreq signal is raised.

Parameters

threshold The threshold

Returns: negative in case of error

int pwm_setEnable	(	int	channel,
		unsigned int	value
	)

Sets the enabled status of the specified channel. After the dma completes a transfer (a chain of control blocks) and 0 gets loaded as control block this is resetted to 0.

Parameters

channel	The channel: 1 or 2
value	It's a boolean: 0=disabled, 1=enabled

Returns: negative in case of error

int pwm_setMode	(	int	channel,
		unsigned int	mode
	)

Sets the mode of the specified channel to PWM or Serializer.

Parameters

channel	The channel: 1 or 2
mode	The mode: 0=PWM, 1=Serializer

Returns: negative in case of error

int pwm_setMSenable	(	int	channel,
		unsigned int	mode
	)

Sets the pwm mode: M/S or the algorithm (see datasheet pag 139)

Parameters

channel	The channel: 1 or 2
mode	The mode: 0=algorithm, 1=M/S

Returns: negative in case of error

int pwm_setRange	(	int	channel,
		uint32_t	range
	)

Sets the range of the specified channel counter.

Parameters

channel	The channel: 1 or 2
range	Range, it's the number of possible pulses in a period.

Returns: negative in case of error

int pwm_setRepeatLastWord	(	int	channel,
		unsigned int	value
	)

Sets the repetition of the last word in the fifo on serializer mode Warning: the pwm peripheral likes to ignore this setting and repeat the last word even if you say it not to.

Parameters

channel	The channel to configure
value	0=don't repeat, 1=repeat

Returns: negative in case of error

int pwm_setSerializerMode	(	int	channel,
		unsigned int	mode
	)

Set the serialized mode to use the fifo or the data register.

Parameters

channel	The channel: 1 or 2
mode	The mode: 0=use data register, 1=use fifo

Returns: negative in case of error

int pwm_writeToFifo ( unsigned int data )

Write the provided data word to the fifo.

Parameters

data The data

Returns: negative in case of error

Functions

Detailed Description

Function Documentation