Detailed Description

PWM driver implementation using the MSP432 Timer_A peripherals.

============================================================================

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

#include <ti/drivers/pwm/PWMTimerMSP432.h>

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

Overview

This driver configures an MSP432 Timer_A peripheral for PWM. If the timer is already in use (by the kernel for instance), PWM instances will not be opened.

When used for PWM generation, each Timer_A can produce up to 6 PWM outputs and this driver manages each output as an independent PWM instance. However since a single period and prescalar are used for all Timer outputs, there are limitations in place to ensure proper operation:

The PWM period and prescalar are calculated and set based on the first instance opened. Opening a second instance will fail if the period is not the same as what was set by the first instance.

The timer is automatically configured in count-up mode using the clock source specified in the hwAttrs structure. In PWM mode, the timer capture/compare register 0 is used as the period register and cannot be used to generate a PWM output.

The period and duty registers are 16 bits wide, thus a prescalar is used to divide the input clock and allow for larger periods. The maximum period supported is calculated as:

MAX_PERIOD = (MAX_PRESCALAR * MAX_MATCH_VALUE) / CYCLES_PER_US
Ex:
- 12 MHz clock: (64 * 65535) / 12 = 349520 microseconds
- 6 MHz clock: (64 * 65535) / 6 = 699040 microseconds
- 3 MHz clock: (64 * 65535) / 3 = 1398080 microseconds

After opening, the PWM_setPeriod() API can be used to change the PWM period. Keep in mind the period is shared by all other PWMs on the timer, so all other PWM outputs on the timer will change. Additionally, a call to PWM_setPeriod() will fail if the new period requires a prescalar different than the one set when initially configured.

MPS432 PWM Driver Configuration

In order to use the PWM APIs, the application is required to define 4 configuration items in the application Board.c file:

An array of PWMTimerMSP432_Object elements, which will be used by by the driver to maintain instance state. Below is an example PWMTimerMSP432_Object array appropriate for the MSP432 Launchpad board:
#include <ti/drivers/PWM.h>

#include <ti/drivers/pwm/PWMTimerMSP432.h>

PWMTimerMSP432_Object pwmTimerMSP432Objects[MSP_EXP432P401R_PWMCOUNT];
An array of PWMTimerMSP432_HWAttrsV2 elements that defines which pin will be used by the corresponding PWM instance (see PWMTimerMSP432_HWAttrs 'pwmPin' field options). Below is an example PWMTimerMSP432_HWAttrsV2 array appropriate for the MSP432 Launchpad board:
const PWMTimerMSP432_HWAttrsV2 pwmTimerMSP432HWAttrs[MSP_EXP432P401R_PWMCOUNT] = {

{

.clockSource = TIMER_A_CLOCKSOURCE_SMCLK,

.pwmPin = PWMTimerMSP432_P2_1_TA1CCR1A

},

{

.clockSource = TIMER_A_CLOCKSOURCE_SMCLK,

.pwmPin = PWMTimerMSP432_P2_2_TA1CCR2A

}

};
An array of PWM_Config elements, one for each PWM instance. Each element of this array identifies the device-specific API function table, the device specific PWM object instance, and the device specific Hardware Attributes to be used for each PWM channel. Below is an example PWM_Config array appropriate for the MSP432 Launchpad board:
const PWM_Config PWM_config[MSP_EXP432P401R_PWMCOUNT] = {

{

.fxnTablePtr = &PWMTimerMSP432_fxnTable,

.object = &pwmTimerMSP432Objects[MSP_EXP432P401R_PWM_TA1_1],

.hwAttrs = &pwmTimerMSP432HWAttrs[MSP_EXP432P401R_PWM_TA1_1]

},

{

.fxnTablePtr = &PWMTimerMSP432_fxnTable,

.object = &pwmTimerMSP432Objects[MSP_EXP432P401R_PWM_TA1_2],

.hwAttrs = &pwmTimerMSP432HWAttrs[MSP_EXP432P401R_PWM_TA1_2]

}

};
A global variable, PWM_count, that informs the driver how many PWM instances are defined:
const uint_least8_t PWM_count = MSP_EXP432P401R_PWMCOUNT;

Power Management

The TI-RTOS power management framework will try to put the device into the most power efficient mode whenever possible. Please see the technical reference manual for further details on each power mode.

The PWMTimerMSP432 driver explicitly sets a power constraint when the PWM is running to prevent LPDS and SHUTDOWN Power modes. The following statements are valid:

After PWM_open(): Clocks are enabled to the timer resource and the configured pwmPin. The device is still allowed to enter LPDS and SHUTDOWN. Dynamic performance level changes are disallowed.
After PWM_start(): DEEPSLEEP, SHUTDOWN_0 and SHUTDOWN_1 modes are disabled. The device can only go to Idle power mode since the high-frequency clock is needed for PWM operation:
After PWM_stop(): Conditions are equal as for after PWM_open
After PWM_close(): The underlying GPTimer is turned off, and the clocks
to the timer and pin are disabled..

#include <stdbool.h>
#include <ti/drivers/PWM.h>
#include <ti/devices/msp432p4xx/driverlib/pmap.h>
#include <ti/devices/msp432p4xx/driverlib/timer_a.h>

Include dependency graph for PWMTimerMSP432.h:

Go to the source code of this file.

Data Structures
struct	PWMTimerMSP432_HWAttrsV2
	PWMTimerMSP432 Hardware attributes. More...

struct	PWMTimerMSP432_Status
	PWMTimerMSP432_Status. More...

struct	PWMTimerMSP432_Object
	PWMTimerMSP432 Object. More...

Macros
Port 2, Pin 0 'pwmPin' setting variations
#define	PWMTimerMSP432_P2_0_TA0CCR1A

#define	PWMTimerMSP432_P2_0_TA0CCR2A

#define	PWMTimerMSP432_P2_0_TA0CCR3A

#define	PWMTimerMSP432_P2_0_TA0CCR4A

#define	PWMTimerMSP432_P2_0_TA1CCR1A

#define	PWMTimerMSP432_P2_0_TA1CCR2A

#define	PWMTimerMSP432_P2_0_TA1CCR3A

#define	PWMTimerMSP432_P2_0_TA1CCR4A

Port 2, Pin 1 'pwmPin' setting variations
#define	PWMTimerMSP432_P2_1_TA0CCR1A

#define	PWMTimerMSP432_P2_1_TA0CCR2A

#define	PWMTimerMSP432_P2_1_TA0CCR3A

#define	PWMTimerMSP432_P2_1_TA0CCR4A

#define	PWMTimerMSP432_P2_1_TA1CCR1A

#define	PWMTimerMSP432_P2_1_TA1CCR2A

#define	PWMTimerMSP432_P2_1_TA1CCR3A

#define	PWMTimerMSP432_P2_1_TA1CCR4A

Port 2, Pin 2 'pwmPin' setting variations
#define	PWMTimerMSP432_P2_2_TA0CCR1A

#define	PWMTimerMSP432_P2_2_TA0CCR2A

#define	PWMTimerMSP432_P2_2_TA0CCR3A

#define	PWMTimerMSP432_P2_2_TA0CCR4A

#define	PWMTimerMSP432_P2_2_TA1CCR1A

#define	PWMTimerMSP432_P2_2_TA1CCR2A

#define	PWMTimerMSP432_P2_2_TA1CCR3A

#define	PWMTimerMSP432_P2_2_TA1CCR4A

Port 2, Pin 3 'pwmPin' setting variations
#define	PWMTimerMSP432_P2_3_TA0CCR1A

#define	PWMTimerMSP432_P2_3_TA0CCR2A

#define	PWMTimerMSP432_P2_3_TA0CCR3A

#define	PWMTimerMSP432_P2_3_TA0CCR4A

#define	PWMTimerMSP432_P2_3_TA1CCR1A

#define	PWMTimerMSP432_P2_3_TA1CCR2A

#define	PWMTimerMSP432_P2_3_TA1CCR3A

#define	PWMTimerMSP432_P2_3_TA1CCR4A

Port 2, Pin 4 'pwmPin' setting variations
#define	PWMTimerMSP432_P2_4_TA0CCR1A

#define	PWMTimerMSP432_P2_4_TA0CCR2A

#define	PWMTimerMSP432_P2_4_TA0CCR3A

#define	PWMTimerMSP432_P2_4_TA0CCR4A

#define	PWMTimerMSP432_P2_4_TA1CCR1A

#define	PWMTimerMSP432_P2_4_TA1CCR2A

#define	PWMTimerMSP432_P2_4_TA1CCR3A

#define	PWMTimerMSP432_P2_4_TA1CCR4A

Port 2, Pin 5 'pwmPin' setting variations
#define	PWMTimerMSP432_P2_5_TA0CCR1A

#define	PWMTimerMSP432_P2_5_TA0CCR2A

#define	PWMTimerMSP432_P2_5_TA0CCR3A

#define	PWMTimerMSP432_P2_5_TA0CCR4A

#define	PWMTimerMSP432_P2_5_TA1CCR1A

#define	PWMTimerMSP432_P2_5_TA1CCR2A

#define	PWMTimerMSP432_P2_5_TA1CCR3A

#define	PWMTimerMSP432_P2_5_TA1CCR4A

Port 2, Pin 6 'pwmPin' setting variations
#define	PWMTimerMSP432_P2_6_TA0CCR1A

#define	PWMTimerMSP432_P2_6_TA0CCR2A

#define	PWMTimerMSP432_P2_6_TA0CCR3A

#define	PWMTimerMSP432_P2_6_TA0CCR4A

#define	PWMTimerMSP432_P2_6_TA1CCR1A

#define	PWMTimerMSP432_P2_6_TA1CCR2A

#define	PWMTimerMSP432_P2_6_TA1CCR3A

#define	PWMTimerMSP432_P2_6_TA1CCR4A

Port 2, Pin 7 'pwmPin' setting variations
#define	PWMTimerMSP432_P2_7_TA0CCR1A

#define	PWMTimerMSP432_P2_7_TA0CCR2A

#define	PWMTimerMSP432_P2_7_TA0CCR3A

#define	PWMTimerMSP432_P2_7_TA0CCR4A

#define	PWMTimerMSP432_P2_7_TA1CCR1A

#define	PWMTimerMSP432_P2_7_TA1CCR2A

#define	PWMTimerMSP432_P2_7_TA1CCR3A

#define	PWMTimerMSP432_P2_7_TA1CCR4A

Port 3, Pin 0 'pwmPin' setting variations
#define	PWMTimerMSP432_P3_0_TA0CCR1A

#define	PWMTimerMSP432_P3_0_TA0CCR2A

#define	PWMTimerMSP432_P3_0_TA0CCR3A

#define	PWMTimerMSP432_P3_0_TA0CCR4A

#define	PWMTimerMSP432_P3_0_TA1CCR1A

#define	PWMTimerMSP432_P3_0_TA1CCR2A

#define	PWMTimerMSP432_P3_0_TA1CCR3A

#define	PWMTimerMSP432_P3_0_TA1CCR4A

Port 3, Pin 1 'pwmPin' setting variations
#define	PWMTimerMSP432_P3_1_TA0CCR1A

#define	PWMTimerMSP432_P3_1_TA0CCR2A

#define	PWMTimerMSP432_P3_1_TA0CCR3A

#define	PWMTimerMSP432_P3_1_TA0CCR4A

#define	PWMTimerMSP432_P3_1_TA1CCR1A

#define	PWMTimerMSP432_P3_1_TA1CCR2A

#define	PWMTimerMSP432_P3_1_TA1CCR3A

#define	PWMTimerMSP432_P3_1_TA1CCR4A

Port 3, Pin 2 'pwmPin' setting variations
#define	PWMTimerMSP432_P3_2_TA0CCR1A

#define	PWMTimerMSP432_P3_2_TA0CCR2A

#define	PWMTimerMSP432_P3_2_TA0CCR3A

#define	PWMTimerMSP432_P3_2_TA0CCR4A

#define	PWMTimerMSP432_P3_2_TA1CCR1A

#define	PWMTimerMSP432_P3_2_TA1CCR2A

#define	PWMTimerMSP432_P3_2_TA1CCR3A

#define	PWMTimerMSP432_P3_2_TA1CCR4A

Port 3, Pin 3 'pwmPin' setting variations
#define	PWMTimerMSP432_P3_3_TA0CCR1A

#define	PWMTimerMSP432_P3_3_TA0CCR2A

#define	PWMTimerMSP432_P3_3_TA0CCR3A

#define	PWMTimerMSP432_P3_3_TA0CCR4A

#define	PWMTimerMSP432_P3_3_TA1CCR1A

#define	PWMTimerMSP432_P3_3_TA1CCR2A

#define	PWMTimerMSP432_P3_3_TA1CCR3A

#define	PWMTimerMSP432_P3_3_TA1CCR4A

Port 3, Pin 4 'pwmPin' setting variations
#define	PWMTimerMSP432_P3_4_TA0CCR1A

#define	PWMTimerMSP432_P3_4_TA0CCR2A

#define	PWMTimerMSP432_P3_4_TA0CCR3A

#define	PWMTimerMSP432_P3_4_TA0CCR4A

#define	PWMTimerMSP432_P3_4_TA1CCR1A

#define	PWMTimerMSP432_P3_4_TA1CCR2A

#define	PWMTimerMSP432_P3_4_TA1CCR3A

#define	PWMTimerMSP432_P3_4_TA1CCR4A

Port 3, Pin 5 'pwmPin' setting variations
#define	PWMTimerMSP432_P3_5_TA0CCR1A

#define	PWMTimerMSP432_P3_5_TA0CCR2A

#define	PWMTimerMSP432_P3_5_TA0CCR3A

#define	PWMTimerMSP432_P3_5_TA0CCR4A

#define	PWMTimerMSP432_P3_5_TA1CCR1A

#define	PWMTimerMSP432_P3_5_TA1CCR2A

#define	PWMTimerMSP432_P3_5_TA1CCR3A

#define	PWMTimerMSP432_P3_5_TA1CCR4A

Port 3, Pin 6 'pwmPin' setting variations
#define	PWMTimerMSP432_P3_6_TA0CCR1A

#define	PWMTimerMSP432_P3_6_TA0CCR2A

#define	PWMTimerMSP432_P3_6_TA0CCR3A

#define	PWMTimerMSP432_P3_6_TA0CCR4A

#define	PWMTimerMSP432_P3_6_TA1CCR1A

#define	PWMTimerMSP432_P3_6_TA1CCR2A

#define	PWMTimerMSP432_P3_6_TA1CCR3A

#define	PWMTimerMSP432_P3_6_TA1CCR4A

Port 3, Pin 7 'pwmPin' setting variations
#define	PWMTimerMSP432_P3_7_TA0CCR1A

#define	PWMTimerMSP432_P3_7_TA0CCR2A

#define	PWMTimerMSP432_P3_7_TA0CCR3A

#define	PWMTimerMSP432_P3_7_TA0CCR4A

#define	PWMTimerMSP432_P3_7_TA1CCR1A

#define	PWMTimerMSP432_P3_7_TA1CCR2A

#define	PWMTimerMSP432_P3_7_TA1CCR3A

#define	PWMTimerMSP432_P3_7_TA1CCR4A

Port 5 'pwmPin' setting variations
#define	PWMTimerMSP432_P5_6_TA2CCR1A

#define	PWMTimerMSP432_P5_7_TA2CCR2A

Port 6 'pwmPin' setting variations
#define	PWMTimerMSP432_P6_6_TA2CCR3A

#define	PWMTimerMSP432_P6_7_TA2CCR4A

Port 7, Pin 0 'pwmPin' setting variations
#define	PWMTimerMSP432_P7_0_TA0CCR1A

#define	PWMTimerMSP432_P7_0_TA0CCR2A

#define	PWMTimerMSP432_P7_0_TA0CCR3A

#define	PWMTimerMSP432_P7_0_TA0CCR4A

#define	PWMTimerMSP432_P7_0_TA1CCR1A

#define	PWMTimerMSP432_P7_0_TA1CCR2A

#define	PWMTimerMSP432_P7_0_TA1CCR3A

#define	PWMTimerMSP432_P7_0_TA1CCR4A

Port 7, Pin 1 'pwmPin' setting variations
#define	PWMTimerMSP432_P7_1_TA0CCR1A

#define	PWMTimerMSP432_P7_1_TA0CCR2A

#define	PWMTimerMSP432_P7_1_TA0CCR3A

#define	PWMTimerMSP432_P7_1_TA0CCR4A

#define	PWMTimerMSP432_P7_1_TA1CCR1A

#define	PWMTimerMSP432_P7_1_TA1CCR2A

#define	PWMTimerMSP432_P7_1_TA1CCR3A

#define	PWMTimerMSP432_P7_1_TA1CCR4A

Port 7, Pin 2 'pwmPin' setting variations
#define	PWMTimerMSP432_P7_2_TA0CCR1A

#define	PWMTimerMSP432_P7_2_TA0CCR2A

#define	PWMTimerMSP432_P7_2_TA0CCR3A

#define	PWMTimerMSP432_P7_2_TA0CCR4A

#define	PWMTimerMSP432_P7_2_TA1CCR1A

#define	PWMTimerMSP432_P7_2_TA1CCR2A

#define	PWMTimerMSP432_P7_2_TA1CCR3A

#define	PWMTimerMSP432_P7_2_TA1CCR4A

Port 7, Pin 3 'pwmPin' setting variations
#define	PWMTimerMSP432_P7_3_TA0CCR1A

#define	PWMTimerMSP432_P7_3_TA0CCR2A

#define	PWMTimerMSP432_P7_3_TA0CCR3A

#define	PWMTimerMSP432_P7_3_TA0CCR4A

#define	PWMTimerMSP432_P7_3_TA1CCR1A

#define	PWMTimerMSP432_P7_3_TA1CCR2A

#define	PWMTimerMSP432_P7_3_TA1CCR3A

#define	PWMTimerMSP432_P7_3_TA1CCR4A

Port 7, Pin 4 'pwmPin' setting variations
#define	PWMTimerMSP432_P7_4_TA0CCR1A

#define	PWMTimerMSP432_P7_4_TA0CCR2A

#define	PWMTimerMSP432_P7_4_TA0CCR3A

#define	PWMTimerMSP432_P7_4_TA0CCR4A

#define	PWMTimerMSP432_P7_4_TA1CCR1A

#define	PWMTimerMSP432_P7_4_TA1CCR2A

#define	PWMTimerMSP432_P7_4_TA1CCR3A

#define	PWMTimerMSP432_P7_4_TA1CCR4A

Port 7, Pin 5 'pwmPin' setting variations
#define	PWMTimerMSP432_P7_5_TA0CCR1A

#define	PWMTimerMSP432_P7_5_TA0CCR2A

#define	PWMTimerMSP432_P7_5_TA0CCR3A

#define	PWMTimerMSP432_P7_5_TA0CCR4A

#define	PWMTimerMSP432_P7_5_TA1CCR1A

#define	PWMTimerMSP432_P7_5_TA1CCR2A

#define	PWMTimerMSP432_P7_5_TA1CCR3A

#define	PWMTimerMSP432_P7_5_TA1CCR4A

Port 7, Pin 6 'pwmPin' setting variations
#define	PWMTimerMSP432_P7_6_TA0CCR1A

#define	PWMTimerMSP432_P7_6_TA0CCR2A

#define	PWMTimerMSP432_P7_6_TA0CCR3A

#define	PWMTimerMSP432_P7_6_TA0CCR4A

#define	PWMTimerMSP432_P7_6_TA1CCR1A

#define	PWMTimerMSP432_P7_6_TA1CCR2A

#define	PWMTimerMSP432_P7_6_TA1CCR3A

#define	PWMTimerMSP432_P7_6_TA1CCR4A

Port 7, Pin 7 'pwmPin' setting variations
#define	PWMTimerMSP432_P7_7_TA0CCR1A

#define	PWMTimerMSP432_P7_7_TA0CCR2A

#define	PWMTimerMSP432_P7_7_TA0CCR3A

#define	PWMTimerMSP432_P7_7_TA0CCR4A

#define	PWMTimerMSP432_P7_7_TA1CCR1A

#define	PWMTimerMSP432_P7_7_TA1CCR2A

#define	PWMTimerMSP432_P7_7_TA1CCR3A

#define	PWMTimerMSP432_P7_7_TA1CCR4A

Port 8, 'pwmPin' setting variations
#define	PWMTimerMSP432_P8_2_TA3CCR2A

Port 9 'pwmPin' setting variations
#define	PWMTimerMSP432_P9_2_TA3CCR3A

#define	PWMTimerMSP432_P9_3_TA3CCR4A

Typedefs
typedef struct PWMTimerMSP432_HWAttrsV2	PWMTimerMSP432_HWAttrsV2
	PWMTimerMSP432 Hardware attributes. More...

typedef struct PWMTimerMSP432_Status	PWMTimerMSP432_Status
	PWMTimerMSP432_Status. More...

typedef struct PWMTimerMSP432_Object	PWMTimerMSP432_Object
	PWMTimerMSP432 Object. More...

Variables
const PWM_FxnTable	PWMTimerMSP432_fxnTable

Typedef Documentation

typedef struct PWMTimerMSP432_HWAttrsV2 PWMTimerMSP432_HWAttrsV2

PWMTimerMSP432 Hardware attributes.

The 'clockSource' field is used by driverlib APIs and therefore must be populated by driverlib macro definitions. For msp432_driverlib these definitions are found in:

timer_a.h

The 'pwmPin' field identifies which physical pin as well as which timer compare register to use for a particular PWM channel. The encoded pin identifier for initializing the 'pwmPin' field must be selected from the PWMTimerMSP432_HWAttrs 'pwmPin' field options macros.

A sample structure is shown below:

 const PWMTimerMSP432_HWAttrsV2 PWMTimerMSP432HWAttrs[] = {
     {
         .clockSource = TIMER_A_CLOCKSOURCE_SMCLK,
         .pwmPin = PWMTimerMSP432_P2_1_TA1CCR1A,
     },
 };

typedef struct PWMTimerMSP432_Status PWMTimerMSP432_Status

PWMTimerMSP432_Status.

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

typedef struct PWMTimerMSP432_Object PWMTimerMSP432_Object

PWMTimerMSP432 Object.

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

Variable Documentation

const PWM_FxnTable PWMTimerMSP432_fxnTable

Detailed Description

Overview

MPS432 PWM Driver Configuration

Power Management

to the timer and pin are disabled..

Data Structures

Macros

Typedefs

Variables

Typedef Documentation

Variable Documentation