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[/] [neorv32/] [trunk/] [sw/] [lib/] [source/] [neorv32_twi.c] - Rev 11
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// ################################################################################################# // # << NEORV32: neorv32_twi.c - Two-Wire Interface Controller (TWI) 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_twi.c * @author Stephan Nolting * @brief Two-Wire Interface Controller (TWI) HW driver source file. * * @note These functions should only be used if the TWI unit was synthesized (IO_TWI_USE = true). **************************************************************************/ #include "neorv32.h" #include "neorv32_twi.h" /**********************************************************************//** * Check if TWI unit was synthesized. * * @return 0 if TWI was not synthesized, 1 if TWI is available. **************************************************************************/ int neorv32_twi_available(void) { if (neorv32_cpu_csr_read(CSR_MFEATURES) & (1 << CPU_MFEATURES_IO_TWI)) { return 1; } else { return 0; } } /**********************************************************************//** * Enable and configure TWI controller. The TWI control register bits are listed in #NEORV32_TWI_CT_enum. * * @param[in] prsc Clock prescaler select (0..7). See #NEORV32_CLOCK_PRSC_enum. * @param[in] irq_en Enable transfer-done interrupt when 1. **************************************************************************/ void neorv32_twi_setup(uint8_t prsc, uint8_t irq_en) { TWI_CT = 0; // reset uint32_t ct_enable = 1; ct_enable = ct_enable << TWI_CT_EN; uint32_t ct_prsc = (uint32_t)(prsc & 0x07); ct_prsc = ct_prsc << TWI_CT_PRSC0; uint32_t ct_irq = (uint32_t)(irq_en & 0x01); ct_irq = ct_irq << TWI_CT_IRQ_EN; TWI_CT = ct_enable | ct_prsc | ct_irq; } /**********************************************************************//** * Disable TWI controller. **************************************************************************/ void neorv32_twi_disable(void) { TWI_CT &= ~((uint32_t)(1 << TWI_CT_IRQ_EN)); } /**********************************************************************//** * Activate sending ACKs by controller (MACK). **************************************************************************/ void neorv32_twi_mack_enable(void) { TWI_CT |= ((uint32_t)(1 << TWI_CT_MACK)); } /**********************************************************************//** * Deacivate sending ACKs by controller (MACK). **************************************************************************/ void neorv32_twi_mack_disable(void) { TWI_CT &= ~((uint32_t)(1 << TWI_CT_MACK)); } /**********************************************************************//** * Generate START condition and send first byte (address including R/W bit). * * @note Blocking function. * * @param[in] a Data byte including 7-bit address and R/W-bit (lsb). * @return 0: ACK received, 1: NACK received. **************************************************************************/ int neorv32_twi_start_trans(uint8_t a) { neorv32_twi_generate_start(); // generate START condition TWI_DATA = (uint32_t)a; // send address while(TWI_CT & (1 << TWI_CT_BUSY)); // wait until idle again // check for ACK/NACK if (TWI_CT & (1 << TWI_CT_ACK)) return 0; // ACK received else return 1; // NACK received } /**********************************************************************//** * Send data byte and also receive data byte (can be read via neorv32_twi_get_data()). * * @note Blocking function. * * @param[in] d Data byte to be send. * @return 0: ACK received, 1: NACK received. **************************************************************************/ int neorv32_twi_trans(uint8_t d) { TWI_DATA = (uint32_t)d; // send data while(TWI_CT & (1 << TWI_CT_BUSY)); // wait until idle again // check for ACK/NACK if (TWI_CT & (1 << TWI_CT_ACK)) return 0; // ACK received else return 1; // NACK received } /**********************************************************************//** * Get received data from last transmission. * * @return 0: Last received data byte. **************************************************************************/ uint8_t neorv32_twi_get_data(void) { return (uint8_t)TWI_DATA; // get RX data from previous transmission } /**********************************************************************//** * Generate STOP condition. * * @note Blocking function. **************************************************************************/ void neorv32_twi_generate_stop(void) { TWI_CT |= (uint32_t)(1 << TWI_CT_STOP); // generate STOP condition while(TWI_CT & (1 << TWI_CT_BUSY)); // wait until idle again } /**********************************************************************//** * Generate START condition. * * @note Blocking function. **************************************************************************/ void neorv32_twi_generate_start(void) { TWI_CT |= (1 << TWI_CT_START); // generate START condition while(TWI_CT & (1 << TWI_CT_BUSY)); // wait until idle again }
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