coinesAPI calls: Streaming feature

Note:

• The below APIs are supported only on PC Target.
• A simpler approach of using coines_attach_interrupt() API for is available for MCU.

coines_config_streaming

Sets the configuration for streaming sensor data.

int16_t coines_config_streaming(uint8_t channel_id, struct coines_streaming_config *stream_config, struct coines_streaming_blocks *data_blocks); 

Arguments:

• channel_id: An integer number that can be used as identifier/index to the sensor data that will be streamed for this setting
• stream_config: Contains information regarding interface settings and streaming configuration.
• coines_streaming_blocks: Contains information regarding numbers of register blocks, range and size of each block.

Note:

The below parameters should always be set:

• data_block.no_of_blocks: number of blocks to stream (must at least be one)
• For each block b:
  • data_block.reg_start_addr[b]: start address of the block in the register map
  • stream_block.no_of_data_bytes[b]: number of addresses to read, starting from the start address

For reading data from I₂C bus,then set the below parameters:

• stream_config.intf = COINES_SENSOR_INTF_I2C;
• stream_config.i2c_bus: I₂C bus (in case of APP2.0, this is always COINES_I2C_BUS_0)
• stream_config.dev_addr: I₂C address of the sensor

For reading data from SPI bus, then set the below parameters:

• stream_config.intf = COINES_SENSOR_INTF_SPI;
• stream_config.spi_bus: SPI bus (in case of APP2.0, this is always COINES_SPI_BUS_0)
• stream_config.cs_pin: CS pin of the sensor, information can be obtained from the shuttle board documentation for the sensor.

When polling mode is requested, set the below parameters: - stream_config.sampling_units:
either milliseconds (COINES_SAMPLING_TIME_IN_MILLI_SEC)
or microseconds (COINES_SAMPLING_TIME_IN_MICRO_SEC) - stream_config.sampling_time: sampling period in the unit as defined in stream_config.sampling_units

When interrupt mode is requested, set the below parameters:

• stream_config.int_pin: pin of the interrupt which shall trigger the sensor read-out. If the interrupt output of the sensor is used, the required information about the pin number can be obtained from the shuttle board documentation for the sensor.
• stream_config.int_timestamp: it can be configured if the sensor data is tagged with a timestamp (COINES_TIMESTAMP_ENABLE) or not (COINES_TIMESTAMP_DISABLE).

coines_start_stop_streaming

Starts or stops sensor data streaming.

int16_t coines_start_stop_streaming(enum coines_streaming_mode stream_mode, uint8_t start_stop);

Arguments:

• stream_mode: streaming mode (either COINES_STREAMING_MODE_POLLING or
  COINES_STREAMING_MODE_INTERRUPT)
• start_stop: flag to either start (COINES_STREAMING_START) or stop (COINES_STREAMING_STOP) the streaming

coines_read_stream_sensor_data

Reads the data streamed from the sensor.

int16_t coines_read_stream_sensor_data(uint8_t sensor_id, uint32_t number_of_samples, uint8_t *data, uint32_t *valid_samples_count);

Arguments:

• sensor_id: id of the sensor
• number_of_samples: number of samples the user wishes to read (not implemented)
• data: data buffer
  • Interrupt streaming - Packet counter + Register data + Timestamp
  • Polling streaming - Register data
• valid_samples_count: number of samples the user has actually received (may be less than number_of_samples)

Example of a packet:

Format of streaming packages

In the above figure, the following meaning apply to the mentioned abreviations:

• r_p: Value at register address p
• a: Size of register block–0
• r_p+a: Value at register address p

Similarly is the case for r_q, j and r_q+j. See the coines_streaming_blocks structure for information regarding register blocks.

The packet counter and the timestamp can be obtained as follows:

packet_counter = (byte3_c << 24) | (byte2_c << 16) | (byte1_c << 8) | (byte0_c);
timestamp = (byte5_t << 40) | (byte4_t << 32) | (byte3_t << 24) | (byte2_t << 16) | (byte1_t << 8) | (byte0_t);

The 48-bit timestamp is enabled by using coines_trigger_timer(COINES_TIMER_START, COINES_TIMESTAMP_ENABLE);

Timestamp in microseconds can be obtained using below formula:

\[ Timestamp\ (\mu s) = \frac{48bit\_timestamp}{30}\]

coines_trigger_timer

Triggers the timer in firmware and also enables or disables the time stamp feature.

int16_t coines_trigger_timer(enum coines_timer_config tmr_cfg,enum coines_time_stamp_config ts_cfg);

Arguments:

• tmr_cfg: start, stop or reset the timer (COINES_TIMER_START, COINES_TIMER_STOP or COINES_TIMER_RESET)
• ts_cfg: Enables/disables microcontroller timestamp (COINES_TIMESTAMP_ENABLE or COINES_TIMESTAMP_DISABLE)