Comparator, High-Speed (r_acmphs)

Functions
fsp_err_t	R_ACMPHS_Open (comparator_ctrl_t *const p_ctrl, comparator_cfg_t const *const p_cfg)
fsp_err_t	R_ACMPHS_InfoGet (comparator_ctrl_t *const p_ctrl, comparator_info_t *const p_info)
fsp_err_t	R_ACMPHS_OutputEnable (comparator_ctrl_t *const p_ctrl)
fsp_err_t	R_ACMPHS_StatusGet (comparator_ctrl_t *const p_ctrl, comparator_status_t *const p_status)
fsp_err_t	R_ACMPHS_Close (comparator_ctrl_t *p_ctrl)

Detailed Description

Driver for the ACMPHS peripheral on RA MCUs. This module implements the Comparator Interface.

Overview

Features

The ACMPHS HAL module supports the following features:

• Callback on rising edge, falling edge or both
• Configurable debounce filter
• Option for comparator output on VCOUT, CMPOUTn¹, or CMPOUT012¹ pin
• ELC event output

Note

1. This output pin is not available on all MCUs.

Configuration

Build Time Configurations for r_acmphs

The following build time configurations are defined in fsp_cfg/r_acmphs_cfg.h:

Configuration	Options	Default	Description
Parameter Checking	Default (BSP) Enabled Disabled	Default (BSP)	If selected code for parameter checking is included in the build.

Configurations for Analog > Comparator, High-Speed (r_acmphs)

This module can be added to the Stacks tab via New Stack > Analog > Comparator, High-Speed (r_acmphs).

Configuration	Options	Default	Description
Name	Name must be a valid C symbol	g_comparator0	Module name.
Channel	Value must be a non-negative integer	0	Select the hardware channel.
Trigger Edge Selector	Rising Falling Both Edge	Both Edge	The trigger specifies when a comparator callback event should occur. Unused if the interrupt priority is disabled or the callback is NULL.
Noise Filter	No Filter 8 16 32	No Filter	Select the PCLK divisor for the hardware digital debounce filter. Larger divisors provide a longer debounce and take longer for the output to update.
Maximum status retries (CMPMON)	Must be a valid non-negative integer between 2 and 32-bit maximum value	1024	Maximum number of status retries.
Output Polarity	Not Inverted Inverted	Not Inverted	When enabled comparator output is inverted. This affects the output read from R_ACMPHS_StatusGet(), the pin output level, and the edge trigger.
Pin Output	Disabled Enabled	Disabled	Turn this on to enable the CMPOUTn signal for this channel. The CMPOUTn signal for each channel is OR'd together and the result is output to VCOUT. More pin output options are available on select MCUs.
Callback	Name must be a valid C symbol	NULL	Define this function in the application. It is called when the Trigger event occurs.
Comparator Interrupt Priority	MCU Specific Options		Select the interrupt priority for the comparator interrupt.
Analog Input Voltage Source (IVCMP)	MCU Specific Options		Select the Analog input voltage source. Channel mentioned in the options represents channel in ACMPHS
Reference Voltage Input Source (IVREF)	MCU Specific Options		Select the Analog reference voltage source. Channel mentioned in the options represents channel in ACMPHS

Clock Configuration

The ACMPHS peripheral is clocked from PCLKB. You can set the PCLKB frequency using the Clocks tab of the RA Configuration editor or by using the CGC Interface at run-time.

Pin Configuration

Comparator output can be enabled or disabled on each channel individually. The VCOUT pin is a logical OR of all comparator outputs.

The IVCMPn pins are used as comparator inputs. The IVREFn pins are used as comparator reference values.

Usage Notes

Noise Filter

When the noise filter is enabled, the ACMPHP0/ACMPHP1 signal is sampled three times based on the sampling clock selected. The filter clock frequency is determined by PCLKB and the comparator_filter_t setting.

Output Polarity

If output polarity is configured as "Inverted" then the VCOUT signal will be inverted and the R_ACMPHS_StatusGet() will return an inverted status.

Limitations

• Once the analog comparator is configured, the program must wait for the stabilization time to elapse before using the comparator.
• When the noise filter is not enabled the hardware requires software debouncing of the output (two consecutive equal values). This is automatically managed in R_ACMPHS_StatusGet but may result in delay or an API error in rare edge cases.
• Constraints apply on the simultaneous use of ACMPHS analog input and ADC analog input. Refer to the "Usage Notes" section in your MCU's User's Manual for the ADC unit(s) for more details.
• To allow ACMPHS0 to cancel Software Standby mode or enter Snooze, set the CSTEN bit to 1 and the CDFS bits to 00 in the CMPCTL0 register.

Examples

Basic Example

The following is a basic example of using the ACMPHS to detect when the analog voltage input to IVCMP rises above the analog voltage input to IVREF. A GPIO output acts as the comparator input and is externally connected to the IVCMP input of the ACMPHS. An analog voltage input should also be supplied to the IVREF input pin.

#define ADC_PGA_BYPASS_VALUE          (0x9999)

/* Connect this control pin to the IVCMP input of the comparator. This can be any GPIO pin
 * that is not input only. */
#define ACMPHS_EXAMPLE_CONTROL_PIN    (BSP_IO_PORT_05_PIN_03)

volatile uint32_t g_comparator_events = 0U;

/* This callback is called when a comparator event occurs. */
void acmphs_example_callback (comparator_callback_args_t * p_args)
{
    FSP_PARAMETER_NOT_USED(p_args);
    g_comparator_events++;
}

void acmphs_example ()
{
    fsp_err_t err = FSP_SUCCESS;

    /* Disable pin register write protection, if enabled */
    R_BSP_PinAccessEnable();

    /*
     * Start with the IVCMP pin low. This example assumes the comparator is configured to trigger
     * when the voltage of the analog input to IVCMP rises above voltage of the analog input to
     * IVREF.
     */
    (void) R_BSP_PinWrite(ACMPHS_EXAMPLE_CONTROL_PIN, BSP_IO_LEVEL_LOW);

    /* Initialize the ACMPHS module */
    err = R_ACMPHS_Open(&g_comparator_ctrl, &g_comparator_cfg);
    assert(FSP_SUCCESS == err);

    /*
     * If an ADC PGA exists for the analog input pin, then the PGA must be manually configured in order for the pin to be used as
     * an IVCMP input. This procedure is slightly different depending on the MCU (See below).
     */

#if BSP_MCU_GROUP_RA6M3

    /* The following applies for MCUs with the ADC peripheral:
     *
     * Bypass the PGA on ADC unit 0.
     * (See Table 50.2 "Input source configuration of the ACMPHS" in the RA6M3 User's Manual (R01UH0886EJ0100)) */
    R_BSP_MODULE_START(FSP_IP_ADC, 0);
    R_ADC0->ADPGACR   = ADC_PGA_BYPASS_VALUE;
    R_ADC0->ADPGADCR0 = 0;
#elif BSP_MCU_GROUP_RA6T2

    /* The following applies for MCUs with the ADC_B peripheral:
     *
     * Configure PGA on ADC unit 0.
     * (See Table 36.11 "PGA Settings and Available Related Functions" in the RA6T2 User's Manual (R01UH0951EJ0100)) */
    R_BSP_MODULE_START(FSP_IP_ADC, 0);
    R_ADC_B->ADPGACR[0] = R_ADC_B0_ADPGACR_PGAGEN_Msk;
#endif

    /* Wait for the minimum stabilization wait time before enabling output. */
    comparator_info_t info;
    R_ACMPHS_InfoGet(&g_comparator_ctrl, &info);
    R_BSP_SoftwareDelay(info.min_stabilization_wait_us, BSP_DELAY_UNITS_MICROSECONDS);

    /* Enable the comparator output */
    (void) R_ACMPHS_OutputEnable(&g_comparator_ctrl);

    /* Set the IVCMP pin high. */
    (void) R_BSP_PinWrite(ACMPHS_EXAMPLE_CONTROL_PIN, BSP_IO_LEVEL_HIGH);

    while (0 == g_comparator_events)
    {
        /* Wait for interrupt. */
    }

    comparator_status_t status;

    /* Check status of comparator, Status will be COMPARATOR_STATE_OUTPUT_HIGH */
    (void) R_ACMPHS_StatusGet(&g_comparator_ctrl, &status);
}

Function Documentation

R_ACMPHS_Open()

fsp_err_t R_ACMPHS_Open	(	comparator_ctrl_t *const	p_ctrl,
		comparator_cfg_t const *const	p_cfg
	)

Configures the comparator and starts operation. Callbacks and pin output are not active until outputEnable() is called. comparator_api_t::outputEnable() should be called after the output has stabilized. Implements comparator_api_t::open().

Comparator inputs must be configured in the application code prior to calling this function.

Return values

FSP_SUCCESS	Open successful.
FSP_ERR_ASSERTION	An input pointer is NULL
FSP_ERR_INVALID_ARGUMENT	An argument is invalid. Window mode (COMPARATOR_MODE_WINDOW) and filter of 1 (COMPARATOR_FILTER_1) are not supported in this implementation.
FSP_ERR_ALREADY_OPEN	The control block is already open or the hardware lock is taken.

R_ACMPHS_InfoGet()

fsp_err_t R_ACMPHS_InfoGet	(	comparator_ctrl_t *const	p_ctrl,
		comparator_info_t *const	p_info
	)

Provides the minimum stabilization wait time in microseconds. Implements comparator_api_t::infoGet().

Return values

FSP_SUCCESS	Information stored in p_info.
FSP_ERR_ASSERTION	An input pointer was NULL.
FSP_ERR_NOT_OPEN	Instance control block is not open.

R_ACMPHS_OutputEnable()

fsp_err_t R_ACMPHS_OutputEnable

(

comparator_ctrl_t *const

p_ctrl

)

Enables the comparator output, which can be polled using comparator_api_t::statusGet(). Also enables pin output and interrupts as configured during comparator_api_t::open(). Implements comparator_api_t::outputEnable().

Return values

FSP_SUCCESS	Comparator output is enabled.
FSP_ERR_ASSERTION	An input pointer was NULL.
FSP_ERR_NOT_OPEN	Instance control block is not open.

R_ACMPHS_StatusGet()

fsp_err_t R_ACMPHS_StatusGet	(	comparator_ctrl_t *const	p_ctrl,
		comparator_status_t *const	p_status
	)

Provides the operating status of the comparator. Implements comparator_api_t::statusGet().

Return values

FSP_SUCCESS	Operating status of the comparator is provided in p_status.
FSP_ERR_ASSERTION	An input pointer was NULL.
FSP_ERR_NOT_OPEN	Instance control block is not open.
FSP_ERR_TIMEOUT	The debounce filter is off and 2 consecutive matching values were not read within 1024 attempts.

R_ACMPHS_Close()

fsp_err_t R_ACMPHS_Close

(

comparator_ctrl_t *

p_ctrl

)

Stops the comparator. Implements comparator_api_t::close().

Return values

FSP_SUCCESS	Instance control block closed successfully.
FSP_ERR_ASSERTION	An input pointer was NULL.
FSP_ERR_NOT_OPEN	Instance control block is not open.