ESP32 Forum

Code: Select all

spi_device_interface_config_t  MY_VSPI_IFcfg = {	1, // uint8 command_bits simply T/R:: For a write, set the first bit to 0, and for a read, set this bit to 1.
		15, // uint8_t address_bits;           /// Default amount of bits in address phase (0-64), used when 
                     //``SPI_TRANS_VARIABLE_ADDR`` is not used, otherwise ignored.
		0, // uint8_t dummy_bits;              /// Amount of dummy bits to insert between address and data phase
		0, // uint8_t mode;                        /// SPI mode (0-3)
		0, // uint8_t duty_cycle_pos;         /// Duty cycle of positive clock, in 1/256th increments (128 = 50%/50% duty). Setting 
                                                                        // this to 0 (=not setting it) is equivalent to setting this to 128.
		0, // uint8_t cs_ena_pretrans;        /// Amount of SPI bit-cycles the cs should be activated before the transmission (0-16). 
                                                                       //  This only works on half-duplex transactions.
		0, // uint8_t cs_ena_posttrans;       /// Amount of SPI bit-cycles the cs should stay active after the transmission (0-16)
                .clock_speed_hz=SPI_MASTER_FREQ_8M/2, //  4MHz for now  < Clock speed, divisors of 80MHz, in 		 
                .input_delay_ns =0, // int input_delay_ns;  Maximum data valid time of slave. The time required between SCLK and MISO
		.spics_io_num = GPIO_VPIN_CS0, //int spics_io_num;        ///< CS GPIO pin for this device, or -1 if not used
		.flags = SPI_DEVICE_HALFDUPLEX,//  uint32_t flags; ///< Bitwise OR of SPI_DEVICE_* flags, one flag for searching
		.queue_size = 4, //int queue_size;  Transaction queue size. This sets how many transactions can be queued using 
                                          //spi_device_queue_trans but not yet finished using spi_device_get_trans_result) at the same time
		.pre_cb = ADI_spi_pre_transfer_callback, // callback pointer transaction_cb_t - empty function
		.post_cb = ADI_spi_post_transfer_callback  // callback pointer  transaction_cb_t - empty function
};
Ret_Val = spi_bus_initialize(My_VSPI,  &My_VSPI_cfg ,  2 ) ; //  using DMA   2 ?  
Ret_Val = spi_bus_add_device(My_VSPI,   VSPI_Cfg_P, &SpiDevHandle );
DMA_ATTR uint32_t  DumpBlock[512];// dump buffer,   2048 bytes

Code: Select all

Spi_StreamRead( const uint16_t Address, uint8_t *Data ,const uint8_t Count )
{  // misc local variable instantiation
	spi_transaction_t trans = { // local stack copy of trans structure
			0, // ,
			1, // command bit to SPI,  1 is MISO I believe
			.addr = Address,
			0, Count*8, &DummyUserVal,    // Total Length, Rcv Bits, &UserVar  Tx only at this time and Rx data size
			.tx_buffer = (void*) 0L,   // Not Used},  // tx then rcv
			.rx_buffer = (void*) DumpBlock // Returned Data }
	};
	// Set the correct command mode, only ctrl_reg has ascending, streaming is always I guess.  
	Ret_Val |= byte_Spi_Send( CONTROL_REG, ASCENDING4W );//  ensure the device is in  Ascending 4Wire Mode
	Ret_Val |= spi_device_polling_transmit( SpiDevHandle, &trans );
        memcpy( Data, DumpBlock, Count); //copy from DMA Block to calling pointer, 
        // other cleanup and return
}