Parallel Data Capture (r_pdc)

Functions
fsp_err_t	R_PDC_Open (capture_ctrl_t *const p_ctrl, capture_cfg_t const *const p_cfg)
	Powers on PDC, handles required initialization described in the hardware manual. More...
fsp_err_t	R_PDC_Close (capture_ctrl_t *const p_ctrl)
	Stops and closes the transfer interface, disables and powers off the PDC, clears internal driver data and disables interrupts. More...
fsp_err_t	R_PDC_CaptureStart (capture_ctrl_t *const p_ctrl, uint8_t *const p_buffer)
	Starts a capture. Enables interrupts. More...
fsp_err_t	R_PDC_StatusGet (capture_ctrl_t *const p_ctrl, capture_status_t *p_status)
fsp_err_t	R_PDC_CallbackSet (capture_ctrl_t *const p_ctrl, void(*p_callback)(capture_callback_args_t *), void const *const p_context, capture_callback_args_t *const p_callback_memory)

Detailed Description

Driver for the PDC peripheral on RA MCUs. This module implements the CAPTURE Interface.

Overview

The PDC peripheral supports interfacing with external cameras by accepting timing and data signals in order to capture incoming data. A callback is invoked every time a frame of data is accepted.

Features

• Capture incoming data into a user defined buffer
• Data bytes per pixel can be configured
• Endianess of the incoming data can be specified
• Supports configuring capture width and height
• Supports configuring vertical and horizontal sync polarity
• Horizontal and Vertical position for image/data capture can be specified
• External clock to the camera module can be adjusted
• Choice between DMA and DTC to transfer out the captured data
• The specified user callback is invoked when a data frame is captured

Configuration

Build Time Configurations for r_pdc

The following build time configurations are defined in fsp_cfg/r_pdc_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 Graphics > Parallel Data Capture (r_pdc)

This module can be added to the Stacks tab via New Stack > Graphics > Parallel Data Capture (r_pdc).

Configuration	Options	Default	Description
General
Name	Name must be a valid C symbol	g_pdc0	Module name.
Input
Input > Signal polarity
HSYNC	High Low	High	Specify the active polarity of the HSYNC signal.
VSYNC	High Low	High	Specify the active polarity of the VSYNC signal.
Input > Capture Specifications
Number of pixels to capture horizontally	Value must be an integer greater than 0	640	Specify the number of horizontal pixels to capture.
Number of lines to capture vertically	Value must be an integer greater than 0	480	Specify the number of vertical pixels to capture.
Horizontal pixel to start capture from	Value must be an integer	0	Specify the horizontal pixel to start capturing image data from. Allows an image smaller than the native resolution of a camera to be captured.
Line to start capture from	Value must be an integer	0	Specify the vertical line to start capturing image data from. Allows an image smaller than the native resolution of a camera to be captured.
Bytes per pixel	Value must be an integer greater than 0	2	Specify the number of bytes per pixel of the captured image data.
Clock divider	CLK/2 CLK/4 CLK/6 CLK/8 CLK/10 CLK/12 CLK/14 CLK/16	CLK/2	Specify the clock divider for clock frequency of the clock input PCKO to the PDC peripheral.
Endianess	Little Big	Little	Specify the endianness of the captured image data.
Output
Output > Buffer
Number of image buffers	Value must be an integer greater than 0	1	Specify the number of buffers to create.
Interrupts
Callback	Name must be a valid C symbol	g_pdc_user_callback	A user callback function must be provided. This callback is invoked for every successful frame capture and any error conditions
PDC Interrupt Priority	MCU Specific Options		Select the PDC interrupt priority.
DTC Interrupt Priority	MCU Specific Options		Select the DTC interrupt priority.

Clock Configuration

The PDC peripheral module uses the PCLKB as its clock source. The maximum clock to the camera module is PCLKB / 2.

Pin Configuration

The PCKO pin is a clock output and should be connected to the clock input of the camera. The PIXCLK pin is a clock input and should be connected to the output pixel clock of the camera. Likewise, the HSYNC and VSYNC pins must be connected to the horizontal and vertical sync signals of the camera, respectively. The PIXD0-PIXD7 pins are the 8-bit data bus input and should be connected to the relevant output pins of the camera.

Note

Camera control and serial communication pins must be configured separately and are not controlled by this module.

Usage Notes

Interrupt Configuration

• PDC error interrupts are used by this module for reporting errors such as overrun, underrun, vertical line number setting and horizontal byte number setting errors.
• In addition to the PDC error interrupts, DMA or DTC interrupts are also used internally to perform data transfer from this peripheral to the specified image buffer.
• Receive data ready interrupt is used as activation source for DMA and DTC trigger.

Enabling Transfer Modules

• An option to select between DMAC or DTC is provided with DMA as the default transfer choice.
• For further details on DMA please refer Transfer (r_dmac)
• For further details on DTC please refer Transfer (r_dtc)

PDC setup with external camera

• Before configuring the external camera device the PDC Open API must be called in order to start clock output.
• Ensure that the memory pointed to by p_buffer is both valid and large enough to store a complete image.
• The amount of space required (in bytes) can be calculated as: size (bytes) = image width (pixels) * image height (lines) * number of bytes per pixel
• Ensure that the size above is divisible by and aligned to 32 bytes.

Examples

Basic Example

This is a basic example of minimal use of the PDC in an application. This example shows how this driver can be used for capturing data from an external I/O device such as an image sensor.

void g_pdc_user_callback (capture_callback_args_t * p_args)
{
    if (PDC_EVENT_TRANSFER_COMPLETE == p_args->event)
    {
        g_capture_ready = true;
    }
}

void basic_example (void)
{
    fsp_err_t err;


    /* Initialize the PDC module */
    err = R_PDC_Open(&g_pdc0_ctrl, &g_pdc0_cfg);


    /* Handle any errors. This function should be defined by the user. */
    assert(FSP_SUCCESS == err);

    /* Initialize the camera module at this point. This implementation is camera vendor specific. */
    camera_module_initialization();

    /* Initialize capture ready flag to false. This gets set to true in PDC callback upon successful frame capture. */
    g_capture_ready = false;


    err = R_PDC_CaptureStart(&g_pdc0_ctrl, g_user_buffer);
    assert(FSP_SUCCESS == err);


    uint32_t timeout_ms = PDC_DELAY_MS;

    /* Since there is nothing else to do, block until Callback triggers*/
    while ((true != g_capture_ready) && timeout_ms)
    {
        R_BSP_SoftwareDelay(1U, BSP_DELAY_UNITS_MILLISECONDS);
        timeout_ms--;;
    }

    if (0U == timeout_ms)
    {
        __BKPT(0);
    }
}

static void camera_module_initialization (void)
{
    /* Camera vendor specific initialization to be done here */
}

Data Structures
struct	pdc_extended_cfg_t
struct	pdc_instance_ctrl_t

Enumerations
enum	pdc_event_t
enum	pdc_clock_division_t
enum	pdc_endian_t
enum	pdc_hsync_polarity_t
enum	pdc_vsync_polarity_t

---

Data Structure Documentation

pdc_extended_cfg_t

struct pdc_extended_cfg_t

Extended configuration structure for PDC.

Data Fields
pdc_clock_division_t	clock_division	Clock divider.
pdc_endian_t	endian	Endian of capture data.
pdc_hsync_polarity_t	hsync_polarity	Polarity of HSYNC input.
pdc_vsync_polarity_t	vsync_polarity	Polarity of VSYNC input.
uint8_t	pdc_ipl	PDC interrupt priority.
uint8_t	transfer_req_ipl	Transfer interrupt priority.
IRQn_Type	pdc_irq	PDC IRQ number.
IRQn_Type	transfer_req_irq	Transfer request IRQ number.
transfer_instance_t const *	p_lower_lvl_transfer	Pointer to the transfer instance the PDC should use.

pdc_instance_ctrl_t

struct pdc_instance_ctrl_t

PDC instance control block. DO NOT INITIALIZE.

Enumeration Type Documentation

pdc_event_t

enum pdc_event_t

PDC events

Enumerator
PDC_EVENT_TRANSFER_COMPLETE	Complete frame transferred by DMAC/DTC.
PDC_EVENT_RX_DATA_READY	Receive data ready interrupt.
PDC_EVENT_FRAME_END	Frame end interrupt.
PDC_EVENT_ERR_OVERRUN	Overrun interrupt.
PDC_EVENT_ERR_UNDERRUN	Underrun interrupt.
PDC_EVENT_ERR_V_SET	Vertical line setting error interrupt.
PDC_EVENT_ERR_H_SET	Horizontal byte number setting error interrupt.

pdc_clock_division_t

enum pdc_clock_division_t

Clock divider applied to PDC clock to provide PCKO output frequency

Enumerator
PDC_CLOCK_DIVISION_2	CLK / 2.
PDC_CLOCK_DIVISION_4	CLK / 4.
PDC_CLOCK_DIVISION_6	CLK / 6.
PDC_CLOCK_DIVISION_8	CLK / 8.
PDC_CLOCK_DIVISION_10	CLK / 10.
PDC_CLOCK_DIVISION_12	CLK / 12.
PDC_CLOCK_DIVISION_14	CLK / 14.
PDC_CLOCK_DIVISION_16	CLK / 16.

pdc_endian_t

enum pdc_endian_t

Endian of captured data

Enumerator
PDC_ENDIAN_LITTLE	Data is in little endian format.
PDC_ENDIAN_BIG	Data is in big endian format.

pdc_hsync_polarity_t

enum pdc_hsync_polarity_t

Polarity of input HSYNC signal

Enumerator
PDC_HSYNC_POLARITY_HIGH	HSYNC signal is active high.
PDC_HSYNC_POLARITY_LOW	HSYNC signal is active low.

pdc_vsync_polarity_t

enum pdc_vsync_polarity_t

Polarity of input VSYNC signal

Enumerator
PDC_VSYNC_POLARITY_HIGH	VSYNC signal is active high.
PDC_VSYNC_POLARITY_LOW	VSYNC signal is active low.

Function Documentation

R_PDC_Open()

fsp_err_t R_PDC_Open	(	capture_ctrl_t *const	p_ctrl,
		capture_cfg_t const *const	p_cfg
	)

Powers on PDC, handles required initialization described in the hardware manual.

Implements capture_api_t::open.

The Open function provides initial configuration for the PDC module. It powers on the module and enables the PCLKO output and the PIXCLK input. Further initialization requires the PIXCLK input to be running in order to be able to reset the PDC as part of its initialization. This clock is input from a camera module and so the reset and further initialization is performed in capture_api_t::captureStart. This function should be called once prior to calling any other PDC API functions. After the PDC is opened the Open function should not be called again without first calling the Close function.

Example:

    /* Initialize the PDC module */
    err = R_PDC_Open(&g_pdc0_ctrl, &g_pdc0_cfg);

Return values

FSP_SUCCESS	Initialization was successful.
FSP_ERR_ASSERTION	One or more of the following parameters is NULL p_cfg is NULL p_api_ctrl is NULL The pointer to the transfer interface in the p_cfg parameter is NULL Callback parameter is NULL. Invalid IRQ number assigned
FSP_ERR_INVALID_ARGUMENT	One or more of the following parameters is incorrect bytes_per_pixel is zero x_capture_pixels is zero y_capture_pixels is zero x_capture_start_pixel + x_capture_pixels is greater than 4095, OR y_capture_start_pixel + y_capture_pixels is greater than 4095
FSP_ERR_ALREADY_OPEN	Module is already open.

R_PDC_Close()

fsp_err_t R_PDC_Close

(

capture_ctrl_t *const

p_ctrl

)

Stops and closes the transfer interface, disables and powers off the PDC, clears internal driver data and disables interrupts.

Implements capture_api_t::close.

Return values

FSP_SUCCESS	Successful close.
FSP_ERR_ASSERTION	p_api_ctrl is NULL
FSP_ERR_NOT_OPEN	Open has not been successfully called.

R_PDC_CaptureStart()

fsp_err_t R_PDC_CaptureStart	(	capture_ctrl_t *const	p_ctrl,
		uint8_t *const	p_buffer
	)

Starts a capture. Enables interrupts.

Implements capture_api_t::captureStart.

Sets up the transfer interface to transfer data from the PDC into the specified buffer. Configures the PDC settings as previously set by the capture_api_t::open API. These settings are configured here as the PIXCLK input must be active for the PDC reset operation. When a capture is complete the callback registered during capture_api_t::open API call will be called.

Example:

    err = R_PDC_CaptureStart(&g_pdc0_ctrl, g_user_buffer);
    assert(FSP_SUCCESS == err);

Return values

FSP_SUCCESS	Capture start successful.
FSP_ERR_ASSERTION	One or more of the following parameters is NULL p_api_ctrl is NULL p_buffer is NULL
FSP_ERR_NOT_OPEN	Open has not been successfully called.
FSP_ERR_IN_USE	PDC transfer is already in progress.
FSP_ERR_TIMEOUT	Reset operation timed out.
FSP_ERR_NOT_INITIALIZED	Callback function has not been set

R_PDC_StatusGet()

fsp_err_t R_PDC_StatusGet	(	capture_ctrl_t *const	p_ctrl,
		capture_status_t *	p_status
	)

Provides the pdc operating status.

Implements capture_api_t::statusGet.

Return values

FSP_SUCCESS	Initialization was successful.
FSP_ERR_ASSERTION	One or more parameters is NULL.
FSP_ERR_NOT_OPEN	Open has not been successfully called.

R_PDC_CallbackSet()

fsp_err_t R_PDC_CallbackSet	(	capture_ctrl_t *const	p_ctrl,
		void(*)(capture_callback_args_t *)	p_callback,
		void const *const	p_context,
		capture_callback_args_t *const	p_callback_memory
	)

Updates the user callback and has option of providing memory for callback structure.

Implements capture_api_t::callbackSet.

Return values

FSP_ERR_UNSUPPORTED

This is just a stub at present