PWMTimerCC3200.h File Reference

Detailed Description

PWM driver implementation using CC3200 General Purpose Timer peripherals.

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The PWM header file should be included in an application as follows:

#include <ti/drivers/PWM.h>
#include <ti/drivers/pwm/PWMTimerCC3200.h>

Refer to PWM.h for a complete description of APIs & example of use.

Operation

This driver configures a CC3200 General Purpose Timer (GPT) in PWM mode. When in PWM mode, each GPT is divided into 2 PWM outputs. This driver manages each output as independent PWM instances. The timer is automatically configured in count-down mode using the system clock as the source.

The period in the PWM_Params structure must be used to set the initial period. After opening, the PWM_control() API can be used to change a period. The period and duty registers are 16 bits wide; thus, prescalars are used to extend period and duty registers. The maximum period supported is calculated as: MAX_PERIOD = (((MAX_PRESCALAR + 1) * MAX_MATCH_VAL) / CYCLES_PER_US) - 1 80 MHz clock: (((255 + 1) * 65535) / 80) - 1 = 209711 microseconds

Below is an example of how to use the PWM_control() to change a period:

int rc = 0;
int newPeriod = 6000;   // Period in microseconds

rc = PWM_control(pwmHandle, PWMTimerCC3200_CHANGE_PERIOD, &newPeriod);
if (rc < 0) {
  // handle error condition
}

Updates to a PWM instance will occur instantaneously (i.e. GPT peripherals do not have shadow registers). Finally, if the duty supplied is greater than the period, the output will remain in active state.

---

#include <ti/drivers/PWM.h>

Include dependency graph for PWMTimerCC3200.h:

Go to the source code of this file.

Data Structures
struct	PWMTimerCC3200_HWAttrs
	PWMTimerCC3200 Hardware attributes. More...
struct	PWMTimerCC3200_Object
	PWMTimerCC3200 Object. More...

Macros
#define	PWMTimerCC3200_CMD_CHANGE_PERIOD   PWM_CMD_RESERVED + 0
	Control command to change the PWM period. More...
#define	PWMTimerCC3200_CHANGE_PERIOD   PWMTimerCC3200_CMD_CHANGE_PERIOD

Typedefs
typedef struct PWMTimerCC3200_HWAttrs	PWMTimerCC3200_HWAttrs
	PWMTimerCC3200 Hardware attributes. More...
typedef struct PWMTimerCC3200_Object	PWMTimerCC3200_Object
	PWMTimerCC3200 Object. More...

Variables
const PWM_FxnTable	PWMTimerCC3200_fxnTable

Macro Definition Documentation

#define PWMTimerCC3200_CHANGE_PERIOD   PWMTimerCC3200_CMD_CHANGE_PERIOD

Typedef Documentation

typedef struct PWMTimerCC3200_HWAttrs PWMTimerCC3200_HWAttrs

PWMTimerCC3200 Hardware attributes.

These fields are used by CC3200 driverlib APIs and therefore must be populated by driverlib macro definitions. For CC3200 driverlib these definitions are found in:

• inc/hw_memmap.h
• driverlib/timer.h

A sample structure is shown below:

const PWMTimerCC3200_HWAttrs PWMTimerCC3200HWAttrs[] = {
    {
        .baseAddr = TIMERA3_BASE,
        .timer = TIMER_A
    },
    {
        .baseAddr = TIMERA3_BASE,
        .timer = TIMER_B
    },
};

typedef struct PWMTimerCC3200_Object PWMTimerCC3200_Object

PWMTimerCC3200 Object.

The application must not access any member variables of this structure!

Variable Documentation

const PWM_FxnTable PWMTimerCC3200_fxnTable