Serialization PHY

PHY layer for serialization. More...

Data Structures
struct	ser_phy_evt_rx_buf_request_params_t
	A struct containing parameters of event of type SER_PHY_EVT_RX_BUF_REQUEST. More...
struct	ser_phy_evt_rx_pkt_received_params_t
	A struct containing parameters of event of type SER_PHY_EVT_RX_PKT_RECEIVED. More...
struct	ser_phy_evt_hw_error_params_t
	A struct containing parameters of event of type SER_PHY_EVT_HW_ERROR. More...
struct	ser_phy_evt_t
	A struct containing events from a Serialization PHY module. More...

Typedefs
typedef void(*	ser_phy_events_handler_t )(ser_phy_evt_t event)
	A type of generic callback function handler to be used by all PHY module events. More...

Enumerations
enum	ser_phy_evt_type_t {   SER_PHY_EVT_TX_PKT_SENT = 0,   SER_PHY_EVT_RX_BUF_REQUEST,   SER_PHY_EVT_RX_PKT_RECEIVED,   SER_PHY_EVT_RX_PKT_DROPPED,   SER_PHY_EVT_RX_OVERFLOW_ERROR,   SER_PHY_EVT_TX_OVERREAD_ERROR,   SER_PHY_EVT_HW_ERROR,   SER_PHY_EVT_TYPE_MAX }
	Serialization PHY module event types. More...

Functions
uint32_t	ser_phy_open (ser_phy_events_handler_t events_handler)
	Function for opening and initializing the PHY module. More...
uint32_t	ser_phy_tx_pkt_send (const uint8_t *p_buffer, uint16_t num_of_bytes)
	Function for transmitting a packet. More...
uint32_t	ser_phy_rx_buf_set (uint8_t *p_buffer)
	Function for setting an RX buffer and enabling reception of data (the PHY flow). More...
void	ser_phy_close (void)
	Function for closing the PHY module. More...
void	ser_phy_interrupts_enable (void)
	Function for enabling the PHY module interrupts. More...
void	ser_phy_interrupts_disable (void)
	Function for disabling the PHY module interrupts. More...

Detailed Description

PHY layer for serialization.

The Serialization PHY library declares functions and definitions of data structures and identifiers (typedef enum) that are used as API of the serialization PHY layer.

Rationale

Each specific PHY layer (SPI, I2C, UART, low power UART etc.) should provide the same API. This allows the layer above (the HAL Transport layer), which is responsible for controlling the PHY layer, memory management, CRC, retransmission etc., to be hardware independent.

Interlayer communication and control

The PHY layer is controlled by the HAL transport layer by calling functions declared in the Serialization PHY library.

The PHY layer communicates events to the HAL transport layer by calling a callback function. A handler to this function is passed in the ser_phy_open function. This callback function should be called with a parameter of type ser_phy_evt_t, filled accordingly to an event to be passed. Types of supported events are defined in ser_phy_evt_type_t.

For example, to pass an event indicating that an RX packet has been successfully received, first a struct of type ser_phy_evt_t must be filled:

ser_phy_evt_t phy_evt;
phy_evt.evt_type = SER_PHY_EVT_RX_PKT_RECEIVED;
phy_evt.evt_params.rx_pkt_received.p_buffer = (pointer to the RX buffer);
phy_evt.evt_params.rx_pkt_received.num_of_bytes = (number of received bytes);

Then, the callback function must be called:

events_handler(phy_evt);

All functions declared in the Serialization PHY file (ser_phy.h) must be implemented. Some events specified in ser_phy_evt_type_t are optional to implement.

Transmitting a packet

Each PHY layer is responsible for adding the PHY header to a packet to be sent. This header consists of a 16-bit field that carries the packet length (the uint16_encode function defined in app_util.h should be used to ensure endianness independence). A pointer to a packet to be sent and length of the packet are parameters of the ser_phy_tx_pkt_send function. When a packet has been transmitted, an event of type SER_PHY_EVT_TX_PKT_SENT should be emitted.

TX - interlayer communication

Receiving a packet

The PHY layer should be able to store only the PHY header (16-bit field carrying the packet length). After the PHY header has been received, the transmission is stopped and the PHY layer must send a request to the HAL transport layer for memory to store the packet - an event of type SER_PHY_EVT_RX_BUF_REQUEST with event parameters defined in ser_phy_evt_rx_buf_request_params_t (the uint16_decode function defined in app_util.h should be used for header decoding to ensure endianness independence). The transmission should be resumed when the ser_phy_rx_buf_set function has been called.

When the ser_phy_rx_buf_set function parameter equals NULL, there is not enough memory to store the packet. However, the packet will be received to a dummy location to ensure continuous communication. After receiving has finished, an event of type SER_PHY_EVT_RX_PKT_DROPPED is generated.

RX dropping - interlayer communication

When the ser_phy_rx_buf_set function parameter is different than NULL, the packet is received to a buffer pointed to by it. After receiving has finished, an event of type SER_PHY_EVT_RX_PKT_RECEIVED is generated with event parameters defined in ser_phy_evt_rx_pkt_received_params_t.

RX - interlayer communication

PHY layer errors

PHY layer errors can be signaled by an event of type SER_PHY_EVT_RX_OVERFLOW_ERROR or SER_PHY_EVT_TX_OVERREAD_ERROR or SER_PHY_EVT_HW_ERROR with event parameters defined in ser_phy_evt_hw_error_params_t.

Available PHY layers

The following PHY layers are available:

• SPI RAW protocol
• SPI_5W RAW protocol
• UART RAW protocol
• UART HCI protocol

Typedef Documentation

typedef void(* ser_phy_events_handler_t)(ser_phy_evt_t event)

A type of generic callback function handler to be used by all PHY module events.

Parameters

[in]

event

Serialization PHY module event.

Enumeration Type Documentation

enum ser_phy_evt_type_t

Serialization PHY module event types.

Enumerator
SER_PHY_EVT_TX_PKT_SENT	Obligatory to implement. An event indicating that a TX packet has been transmitted.
SER_PHY_EVT_RX_BUF_REQUEST	Obligatory to implement. An event indicating that the PHY layer needs a buffer for an RX packet. The PHY flow should be blocked until the ser_phy_rx_buf_set function is called.
SER_PHY_EVT_RX_PKT_RECEIVED	Obligatory to implement. An event indicating that an RX packet has been successfully received.
SER_PHY_EVT_RX_PKT_DROPPED	Obligatory to implement. An event indicating that the RX packet receiving has been finished but the packet was discarded because it was longer than available the buffer.
SER_PHY_EVT_RX_OVERFLOW_ERROR	Optional to implement. An event indicating that more information has been transmitted than the PHY module could handle.
SER_PHY_EVT_TX_OVERREAD_ERROR	Optional to implement. An event indicating that the PHY module was forced to transmit more information than possessed.
SER_PHY_EVT_HW_ERROR	Optional to implement. An event indicating a hardware error in the PHY module.
SER_PHY_EVT_TYPE_MAX	Enumeration upper bound.

Function Documentation

void ser_phy_close

(

void

)

Function for closing the PHY module.

Note

The function disables hardware, resets internal module states, and unregisters the events callback function.

void ser_phy_interrupts_disable

(

void

)

Function for disabling the PHY module interrupts.

Note

The function disables all interrupts that are used by the PHY module (and only those).

void ser_phy_interrupts_enable

(

void

)

Function for enabling the PHY module interrupts.

Note

The function enables all interrupts that are used by the PHY module (and only those).

uint32_t ser_phy_open

(

ser_phy_events_handler_t

events_handler

)

Function for opening and initializing the PHY module.

Note

The function initializes hardware and internal module states, and registers callback function to be used by all PHY module events.

Warning

If the function has been already called, the function ser_phy_close has to be called before ser_phy_open can be called again.

Parameters

[in]

events_handler

Generic callback function handler to be used by all PHY module events.

Return values

NRF_SUCCESS	Operation success.
NRF_ERROR_INVALID_STATE	Operation failure. The function has been already called. To call it again, the function ser_phy_close has to be called first.
NRF_ERROR_NULL	Operation failure. NULL pointer supplied.
NRF_ERROR_INVALID_PARAM	Operation failure. Hardware initialization parameters are not supported.

uint32_t ser_phy_rx_buf_set

(

uint8_t *

p_buffer

)

Function for setting an RX buffer and enabling reception of data (the PHY flow).

Note

The function has to be called as a response to an event of type SER_PHY_EVT_RX_BUF_REQUEST. The function sets an RX buffer and enables reception of data (enables the PHY flow). Size of a buffer pointed by the p_buffer parameter should be at least equal to the num_of_bytes parameter passed within the event (ser_phy_evt_rx_buf_request_params_t), or p_buffer should be equal to NULL if there is not enough memory. When p_buffer is different from NULL and num_of_bytes octets have been received, an event of type SER_PHY_EVT_RX_PKT_RECEIVED is generated (ser_phy_evt_rx_pkt_received_params_t). When p_buffer is equal to NULL, data is received to dummy location to ensure continuous communication. Then, if num_of_bytes octets have been received, an event of type SER_PHY_EVT_RX_PKT_DROPPED is generated.

Parameters

[in]

p_buffer

Pointer to an RX buffer in which to receive.

Return values

NRF_SUCCESS	Operation success.
NRF_ERROR_INVALID_STATE	Operation failure. A buffer was set without request.

uint32_t ser_phy_tx_pkt_send	(	const uint8_t *	p_buffer,
		uint16_t	num_of_bytes
	)

Function for transmitting a packet.

Note

The function adds a packet pointed by p_buffer parameter to a transmission queue and schedules generation of an event of type SER_PHY_EVT_TX_PKT_SENT upon transmission completion.

Parameters

[in]	p_buffer	Pointer to a buffer to transmit.
[in]	num_of_bytes	Number of octets to transmit. Must be more than 0.

Return values

NRF_SUCCESS	Operation success. Packet was added to the transmission queue and event will be send upon transmission completion.
NRF_ERROR_NULL	Operation failure. NULL pointer supplied.
NRF_ERROR_INVALID_PARAM	Operation failure. The num_of_bytes parameter equal to 0.
NRF_ERROR_BUSY	Operation failure. Transmitting of a packet in progress.