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[/] [neorv32/] [trunk/] [sw/] [lib/] [source/] [neorv32_spi.c] - Rev 18
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// ################################################################################################# // # << NEORV32: neorv32_spi.c - Serial Peripheral Interface Controller (SPI) HW Driver >> # // # ********************************************************************************************* # // # BSD 3-Clause License # // # # // # Copyright (c) 2020, Stephan Nolting. All rights reserved. # // # # // # Redistribution and use in source and binary forms, with or without modification, are # // # permitted provided that the following conditions are met: # // # # // # 1. Redistributions of source code must retain the above copyright notice, this list of # // # conditions and the following disclaimer. # // # # // # 2. Redistributions in binary form must reproduce the above copyright notice, this list of # // # conditions and the following disclaimer in the documentation and/or other materials # // # provided with the distribution. # // # # // # 3. Neither the name of the copyright holder nor the names of its contributors may be used to # // # endorse or promote products derived from this software without specific prior written # // # permission. # // # # // # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS # // # OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF # // # MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE # // # COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, # // # EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE # // # GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED # // # AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING # // # NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED # // # OF THE POSSIBILITY OF SUCH DAMAGE. # // # ********************************************************************************************* # // # The NEORV32 Processor - https://github.com/stnolting/neorv32 (c) Stephan Nolting # // ################################################################################################# /**********************************************************************//** * @file neorv32_spi.c * @author Stephan Nolting * @brief Serial peripheral interface controller (SPI) HW driver source file. * * @note These functions should only be used if the SPI unit was synthesized (IO_SPI_USE = true). **************************************************************************/ #include "neorv32.h" #include "neorv32_spi.h" /**********************************************************************//** * Check if SPI unit was synthesized. * * @return 0 if SPI was not synthesized, 1 if SPI is available. **************************************************************************/ int neorv32_spi_available(void) { if (SYSINFO_FEATURES & (1 << SYSINFO_FEATURES_IO_SPI)) { return 1; } else { return 0; } } /**********************************************************************//** * Enable and configure SPI controller. The SPI control register bits are listed in #NEORV32_SPI_CT_enum. * * @param[in] prsc Clock prescaler select (0..7). See #NEORV32_CLOCK_PRSC_enum. * @param[in] clk_polarity Idle clock polarity (0, 1). * @param[in] dir Shift direction (0: MSB first, 1: LSB first). * @param[in] data_size Data transfer size (0: 8-bit, 1: 16-bit, 2: 24-bit, 3: 32-bit). * @param[in] irq_en Enable transfer-done interrupt when 1. **************************************************************************/ void neorv32_spi_setup(uint8_t prsc, uint8_t clk_polarity, uint8_t dir, uint8_t data_size, uint8_t irq_en) { SPI_CT = 0; // reset uint32_t ct_enable = 1; ct_enable = ct_enable << SPI_CT_EN; uint32_t ct_prsc = (uint32_t)(prsc & 0x07); ct_prsc = ct_prsc << SPI_CT_PRSC0; uint32_t ct_polarity = (uint32_t)(clk_polarity & 0x01); ct_polarity = ct_polarity << SPI_CT_CPHA; uint32_t ct_dir = (uint32_t)(dir & 0x01); ct_dir = ct_dir << SPI_CT_DIR; uint32_t ct_size = (uint32_t)(data_size & 0x03); ct_size = ct_size << SPI_CT_SIZE0; uint32_t ct_irq = (uint32_t)(irq_en & 0x01); ct_irq = ct_irq << SPI_CT_IRQ_EN; SPI_CT = ct_enable | ct_prsc | ct_polarity | ct_dir | ct_size | ct_irq; } /**********************************************************************//** * Disable and SPI controller. **************************************************************************/ void neorv32_spi_disable(void) { SPI_CT &= ~((uint32_t)(1 << SPI_CT_EN)); } /**********************************************************************//** * Activate SPI chip select signal. * * @note The chip select output lines are LOW when activated. * * @param cs Chip select line to activate (0..7). **************************************************************************/ void neorv32_spi_cs_en(uint8_t cs) { uint32_t cs_mask = (uint32_t)(1 << (cs & 0x07)); cs_mask = cs_mask << SPI_CT_CS0; SPI_CT |= cs_mask; } /**********************************************************************//** * Deactivate SPI chip select signal. * * @note The chip select output lines are HIGH when deactivated. * * @param cs Chip select line to deactivate (0..7). **************************************************************************/ void neorv32_spi_cs_dis(uint8_t cs) { uint32_t cs_mask = (uint32_t)(1 << (cs & 0x07)); cs_mask = cs_mask << SPI_CT_CS0; SPI_CT &= ~cs_mask; } /**********************************************************************//** * Initiate SPI transfer. * * @note This function is blocking. * * @param tx_data Transmit data (8/16/24/32-bit, LSB-aligned). * @return Receive data (8/16/24/32-bit, LSB-aligned). **************************************************************************/ uint32_t neorv32_spi_trans(uint32_t tx_data) { SPI_DATA = tx_data; // trigger transfer while((SPI_CT & (1<<SPI_CT_BUSY)) != 0); // wait for current transfer to finish return SPI_DATA; }
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