Synchronous Serial Interface#

ssi_event_typedef_t#

ssi_event_typedef_t

Enumeration for different SSI callback events.

ssi_peripheral_clock_mode_t#

ssi_peripheral_clock_mode_t

Enumeration for different SSI peripheral clock modes.

sl_ssi_instance_t#

sl_ssi_instance_t

Enumeration for different SSI peripheral device modes.

sl_ssi_slave_number_t#

sl_ssi_slave_number_t

Enumeration for SSI secondary numbers.

sl_ssi_power_state_t#

sl_ssi_power_state_t

ARM power state structure.

Typedef for ARM power state structure.

sl_ssi_status_t#

sl_ssi_status_t

ARM SPI status.

Typedef for ARM SPI status.

sl_ssi_driver_t#

sl_ssi_driver_t

SSI driver structure.

Typedef for SSI driver structure.

sl_ssi_handle_t#

sl_ssi_handle_t

SSI handle to be passed into APIs.

Typedef for SSI handle to be passed into APIs.

sl_ssi_signal_event_t#

sl_ssi_signal_event_t

Callback typedef for SSI.

Typedef for callback function for SSI.

sl_si91x_ssi_configure_clock#

sl_status_t sl_si91x_ssi_configure_clock (sl_ssi_clock_config_t * clock_config)

To configure the SSI clock.

Configures the PLL clock and SOC clock with the values set by the user in the clock configuration structure.

Returns

• sl_status_t Status code indicating the result:

  • SL_STATUS_OK (0x0000) - Success, timer clock-source parameters configured properly.

  • SL_STATUS_FAIL (0x0001) - Generic error.

  • SL_STATUS_NOT_INITIALIZED (0x0011) - Clock is not initialized.

  • SL_STATUS_INVALID_PARAMETER (0x0021) - Parameters are invalid.

  • SL_STATUS_NULL_POINTER (0x0022) - The parameter is a null pointer.

For more information on status codes, see SL STATUS DOCUMENTATION.

sl_si91x_ssi_init#

sl_status_t sl_si91x_ssi_init (sl_ssi_instance_t instance, sl_ssi_handle_t * ssi_handle)

To initialize the SSI.

This API initializes the SSI. If DMA is enabled, it also initializes the DMA module. Pass the address of the pointer for storing the SSI Primary/Secondary/ULP Primary handle, which can be used in the future for other function calls.

Returns

• sl_status_t Status code indicating the result:

  • SL_STATUS_OK (0x0000) - Success.

  • SL_STATUS_BUSY (0x0004) - Driver is busy.

  • SL_STATUS_INVALID_PARAMETER (0x0021) - Parameters are invalid.

For more information on status codes, see SL STATUS DOCUMENTATION.

sl_si91x_ssi_deinit#

sl_status_t sl_si91x_ssi_deinit (sl_ssi_handle_t ssi_handle)

To uninitialize the SSI.

This API will uninitialize the SSI. If DMA is enabled, it also uninitializes the DMA module.

Returns

• sl_status_t Status code indicating the result:

  • SL_STATUS_OK (0x0000) - Success.

  • SL_STATUS_NULL_POINTER (0x0022) - The parameter is a null pointer.

For more information on status codes, see SL STATUS DOCUMENTATION.

Note

• When the SSI module is used in combination with other peripherals, see the notes below while deinitializing in the application:

  1. Whenever sl_si91x_ssi_deinit() is called, it will disable the clock for the peripheral. To power off the peripheral, we have to power down the power domain (PERI_EFUSE) which contains the following peripherals: USART, UART, I2C, SSI Master, SSI Slave, Generic-SPI Master, I2S Master, I2S Slave, Micro-DMA Controller, Config Timer, Random-Number Generator, CRC Accelerator, SIO, QEI, MCPWM, and EFUSE. Use the following API to power down the particular power domain if other peripherals are not being used: sl_si91x_peri_efuse_power_down(power_down);

  2. A few peripherals (ULP Peripherals, UULP Peripherals, GPDMA, and SDIO-SPI) have separate domains; those can be powered down independently. For additional details, see the Power architecture section in the Hardware Reference Manual. Here, ULP_UART has a separate power domain ULPSS_PWRGATE_ULP_UART, which can be powered down independently. See the rsi_power_save.h file for all power gate definitions.

sl_si91x_ssi_set_configuration#

sl_status_t sl_si91x_ssi_set_configuration (sl_ssi_handle_t ssi_handle, sl_ssi_control_config_t * control_configuration, sl_ssi_slave_number_t slave_number)

To control and configure the SSI.

This API will control and configure the SSI. As part of that, the following parameters are configured:

• Mode (Primary/Secondary/ULP Primary)

• Bit width (4 bits to 16 bits)

• Clock mode/Frame format (mode0 to mode3, TI, and Microwire)

• Bitrate (10 Mbps to 40 Mbps)

• Rx sample delay (0 to 63)

Returns

• sl_status_t Status code indicating the result:

  • SL_STATUS_OK (0x0000) - Success.

  • SL_STATUS_FAIL (0x0001) - Function failed.

  • SL_STATUS_BUSY (0x0004) - Driver is busy.

  • SL_STATUS_NOT_SUPPORTED (0x000F) - Parameter is not supported.

  • SL_STATUS_INVALID_PARAMETER (0x0021) - Parameters are invalid.

  • SL_STATUS_NULL_POINTER (0x0022) - The parameter is a null pointer.

  • SL_STATUS_INVALID_MODE (0x0024) - Slave select mode is invalid.

  • SL_STATUS_INVALID_TYPE (0x0026) - SPI frame format is not valid.

  • SL_STATUS_INVALID_RANGE (0x0028) - Data bits (frame length) are not in range.

For more information on status codes, see SL STATUS DOCUMENTATION.

sl_si91x_ssi_receive_data#

sl_status_t sl_si91x_ssi_receive_data (sl_ssi_handle_t ssi_handle, void * data, uint32_t data_length)

To receive data from the secondary device.

This API will receive data from the secondary device. If DMA is enabled, it configures the DMA channel and required parameters. When the received data is equal to the data_length passed in this function, a callback event is generated which can be registered using sl_si91x_ssi_register_event_callback.

• Pre-conditions:

  • sl_si91x_ssi_configure_clock

  • sl_si91x_ssi_init

  • sl_si91x_ssi_set_configuration

  • sl_si91x_ssi_set_slave_number

Returns

• sl_status_t Status code indicating the result:

  • SL_STATUS_OK (0x0000) - Success.

  • SL_STATUS_FAIL (0x0001) - Function failed.

  • SL_STATUS_BUSY (0x0004) - Driver is busy.

  • SL_STATUS_INVALID_PARAMETER (0x0021) - Parameters are invalid.

  • SL_STATUS_NULL_POINTER (0x0022) - The parameter is a null pointer.

For more information on status codes, see SL STATUS DOCUMENTATION.

sl_si91x_ssi_send_data#

sl_status_t sl_si91x_ssi_send_data (sl_ssi_handle_t ssi_handle, const void * data, uint32_t data_length)

To send data to the secondary device.

This API will send data to the secondary device. If DMA is enabled, it configures the DMA channel and required parameters. When the sent data is equal to the data_length passed in this function, a callback event is generated which can be registered using sl_si91x_ssi_register_event_callback.

• Pre-conditions:

  • sl_si91x_ssi_configure_clock

  • sl_si91x_ssi_init

  • sl_si91x_ssi_set_configuration

  • sl_si91x_ssi_set_slave_number

Returns

• sl_status_t Status code indicating the result:

  • SL_STATUS_OK (0x0000) - Success.

  • SL_STATUS_FAIL (0x0001) - Function failed.

  • SL_STATUS_BUSY (0x0004) - Driver is busy.

  • SL_STATUS_INVALID_PARAMETER (0x0021) - Parameters are invalid.

  • SL_STATUS_NULL_POINTER (0x0022) - The parameter is a null pointer.

For more information on status codes, see SL STATUS DOCUMENTATION.

sl_si91x_ssi_transfer_data#

sl_status_t sl_si91x_ssi_transfer_data (sl_ssi_handle_t ssi_handle, const void * data_out, void * data_in, uint32_t data_length)

To send and receive data to the secondary device simultaneously.

If DMA is enabled, it configures the DMA channel and required parameters. When the received data and sent data are equal to the data_length passed in this function, a callback event is generated which can be registered using sl_si91x_ssi_register_event_callback.

• Pre-conditions:

  • sl_si91x_ssi_configure_clock

  • sl_si91x_ssi_init

  • sl_si91x_ssi_set_configuration

  • sl_si91x_ssi_set_slave_number

Returns

• sl_status_t Status code indicating the result:

  • SL_STATUS_OK (0x0000) - Success.

  • SL_STATUS_FAIL (0x0001) - Function failed.

  • SL_STATUS_BUSY (0x0004) - Driver is busy.

  • SL_STATUS_INVALID_PARAMETER (0x0021) - Parameters are invalid.

  • SL_STATUS_NULL_POINTER (0x0022) - The parameter is a null pointer.

For more information on status codes, see SL STATUS DOCUMENTATION.

sl_si91x_ssi_get_version#

sl_ssi_version_t sl_si91x_ssi_get_version (void )

To get the SSI version.

This API retrieves the SSI version. It returns the API version of SSI.

Returns

• sl_ssi_version_t Structure containing the driver version.

sl_si91x_ssi_get_status#

sl_ssi_status_t sl_si91x_ssi_get_status (sl_ssi_handle_t ssi_handle)

To get the transfer status of SSI.

This API retrieves the transfer status of SSI. It returns the sl_ssi_status_t type structure. The members are:

• Busy

• Data Lost

• Mode Fault It is generally used to poll the busy status of SSI Master/ULP Master.

• Pre-conditions:

  • sl_si91x_ssi_configure_clock

  • sl_si91x_ssi_init

  • sl_si91x_ssi_set_configuration

Returns

• sl_ssi_status_t Structure containing the transfer status.

sl_si91x_ssi_get_rx_data_count#

uint32_t sl_si91x_ssi_get_rx_data_count (sl_ssi_handle_t ssi_handle)

To get the data receive count of the SSI.

This API retrieves the data receive count of the SSI and returns the number of data items received at the time of the function call.

• Pre-conditions:

  • sl_si91x_ssi_configure_clock

  • sl_si91x_ssi_init

  • sl_si91x_ssi_set_configuration

Returns

• uint32_t Value of the RX data count.

sl_si91x_ssi_get_tx_data_count#

uint32_t sl_si91x_ssi_get_tx_data_count (sl_ssi_handle_t ssi_handle)

To get the transmit data count of the SSI.

This API retrieves the transmit data count of the SSI. It returns the number of data items transmitted at the time of the function call.

• Pre-conditions:

  • sl_si91x_ssi_configure_clock

  • sl_si91x_ssi_init

  • sl_si91x_ssi_set_configuration

Returns

• uint32_t Value of the TX data count.

sl_si91x_ssi_register_event_callback#

sl_status_t sl_si91x_ssi_register_event_callback (sl_ssi_handle_t ssi_handle, sl_ssi_signal_event_t callback_event)

To register the user event callback.

This API registers the callback (that is, stores the callback function address and passes it to the variable that is called in the Interrupt Handler). If another callback is registered without unregistering the previous callback, it returns an error code as follows. Therefore, it is mandatory to unregister the callback before registering another callback.

Returns

• sl_status_t Status code indicating the result:

  • SL_STATUS_OK (0x0000) - Success.

  • SL_STATUS_BUSY (0x0004) - The callback is already registered, unregister the previous callback before registering a new one.

  • SL_STATUS_NULL_POINTER (0x0022) - The parameter is a null pointer.

For more information on status codes, see SL STATUS DOCUMENTATION.

sl_si91x_ssi_unregister_event_callback#

void sl_si91x_ssi_unregister_event_callback (void )

To unregister the user event callback.

This API unregisters the callback, i.e., clears the callback function address and passes a NULL value to the variable.

• Pre-conditions:

  • sl_si91x_ssi_register_event_callback

sl_si91x_ssi_get_clock_division_factor#

uint32_t sl_si91x_ssi_get_clock_division_factor (sl_ssi_handle_t ssi_handle)

To fetch the clock division factor.

The clock division factor is calculated based on the peripheral clock configured. It decides the baud rate of SSI.

Returns

• uint32_t The value of the clock division factor.

sl_si91x_ssi_get_frame_length#

uint32_t sl_si91x_ssi_get_frame_length (sl_ssi_handle_t ssi_handle)

To fetch the frame length (bit width) of the SSI.

This API retrieves the frame length, which ranges between 4 and 16 bits.

Returns

• uint32_t The value of the frame length.

sl_si91x_ssi_get_tx_fifo_threshold#

uint32_t sl_si91x_ssi_get_tx_fifo_threshold (sl_ssi_handle_t ssi_handle)

To fetch the transmit FIFO threshold value.

This API retrieves the transmit FIFO threshold value, which controls the level of entries at which the transmit FIFO controller triggers an interrupt.

Returns

• uint32_t The value of the transmit FIFO threshold.

sl_si91x_ssi_get_rx_fifo_threshold#

uint32_t sl_si91x_ssi_get_rx_fifo_threshold (sl_ssi_handle_t ssi_handle)

To fetch the receiver FIFO threshold value.

This API retrieves the receiver FIFO threshold value, which controls the level of entries at which the receive FIFO controller triggers an interrupt.

Returns

• uint32_t The value of the receiver FIFO threshold.

sl_si91x_ssi_get_receiver_sample_delay#

uint32_t sl_si91x_ssi_get_receiver_sample_delay (sl_ssi_handle_t ssi_handle)

To fetch the receiver sample delay value.

This API is used to delay the sample of the RX input signal. Each value represents a single ssi_clk delay on the sample of the rxd signal.

Returns

• uint32_t The value of the receiver sample delay.

sl_si91x_ssi_set_slave_number#

__STATIC_INLINE sl_status_t sl_si91x_ssi_set_slave_number (uint8_t number)

To set the secondary number in multi-secondary operation.

For single secondary operation, this API also needs to be called before transferring the data.

Returns

• sl_status_t Status code indicating the result:

  • SL_STATUS_OK (0x0000) - Success

  • SL_STATUS_INVALID_PARAMETER (0x0021) - Invalid parameter

For more information on status codes, see SL STATUS DOCUMENTATION.