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// #################################################################################################
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// # << NEORV32: neorv32_twi.c - Two-Wire Interface Controller (TWI) HW Driver >> #
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// # << NEORV32: neorv32_twi.c - Two-Wire Interface Controller (TWI) HW Driver >> #
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// # ********************************************************************************************* #
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// # ********************************************************************************************* #
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// # BSD 3-Clause License #
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// # BSD 3-Clause License #
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// # #
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// # #
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// # Copyright (c) 2021, Stephan Nolting. All rights reserved. #
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// # Copyright (c) 2021, Stephan Nolting. All rights reserved. #
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// # #
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// # #
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// # Redistribution and use in source and binary forms, with or without modification, are #
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// # Redistribution and use in source and binary forms, with or without modification, are #
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// # permitted provided that the following conditions are met: #
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// # permitted provided that the following conditions are met: #
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// # #
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// # #
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// # 1. Redistributions of source code must retain the above copyright notice, this list of #
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// # 1. Redistributions of source code must retain the above copyright notice, this list of #
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// # conditions and the following disclaimer. #
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// # conditions and the following disclaimer. #
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// # #
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// # #
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// # 2. Redistributions in binary form must reproduce the above copyright notice, this list of #
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// # 2. Redistributions in binary form must reproduce the above copyright notice, this list of #
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// # conditions and the following disclaimer in the documentation and/or other materials #
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// # conditions and the following disclaimer in the documentation and/or other materials #
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// # provided with the distribution. #
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// # provided with the distribution. #
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// # #
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// # #
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// # 3. Neither the name of the copyright holder nor the names of its contributors may be used to #
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// # 3. Neither the name of the copyright holder nor the names of its contributors may be used to #
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// # endorse or promote products derived from this software without specific prior written #
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// # endorse or promote products derived from this software without specific prior written #
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// # permission. #
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// # permission. #
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// # #
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// # #
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// # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS #
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// # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS #
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// # OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF #
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// # MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE #
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// # MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE #
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// # COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, #
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// # COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, #
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// # EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE #
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// # GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED #
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// # GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED #
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// # AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING #
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// # NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED #
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// # NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED #
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// # OF THE POSSIBILITY OF SUCH DAMAGE. #
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// # OF THE POSSIBILITY OF SUCH DAMAGE. #
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// # ********************************************************************************************* #
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// # ********************************************************************************************* #
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// # The NEORV32 Processor - https://github.com/stnolting/neorv32 (c) Stephan Nolting #
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// # The NEORV32 Processor - https://github.com/stnolting/neorv32 (c) Stephan Nolting #
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// #################################################################################################
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// #################################################################################################
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/**********************************************************************//**
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/**********************************************************************//**
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* @file neorv32_twi.c
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* @file neorv32_twi.c
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* @author Stephan Nolting
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* @author Stephan Nolting
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* @brief Two-Wire Interface Controller (TWI) HW driver source file.
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* @brief Two-Wire Interface Controller (TWI) HW driver source file.
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*
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*
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* @note These functions should only be used if the TWI unit was synthesized (IO_TWI_EN = true).
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* @note These functions should only be used if the TWI unit was synthesized (IO_TWI_EN = true).
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**************************************************************************/
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**************************************************************************/
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#include "neorv32.h"
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#include "neorv32.h"
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#include "neorv32_twi.h"
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#include "neorv32_twi.h"
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/**********************************************************************//**
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/**********************************************************************//**
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* Check if TWI unit was synthesized.
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* Check if TWI unit was synthesized.
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*
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*
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* @return 0 if TWI was not synthesized, 1 if TWI is available.
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* @return 0 if TWI was not synthesized, 1 if TWI is available.
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**************************************************************************/
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**************************************************************************/
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int neorv32_twi_available(void) {
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int neorv32_twi_available(void) {
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if (SYSINFO_FEATURES & (1 << SYSINFO_FEATURES_IO_TWI)) {
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if (NEORV32_SYSINFO.SOC & (1 << SYSINFO_SOC_IO_TWI)) {
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return 1;
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return 1;
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}
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}
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else {
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else {
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return 0;
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return 0;
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}
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}
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}
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}
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/**********************************************************************//**
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/**********************************************************************//**
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* Enable and configure TWI controller. The TWI control register bits are listed in #NEORV32_TWI_CT_enum.
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* Enable and configure TWI controller. The TWI control register bits are listed in #NEORV32_TWI_CTRL_enum.
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*
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*
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* @param[in] prsc Clock prescaler select (0..7). See #NEORV32_CLOCK_PRSC_enum.
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* @param[in] prsc Clock prescaler select (0..7). See #NEORV32_CLOCK_PRSC_enum.
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* @param[in] ckst_en Enable clock-stretching by peripherals when 1.
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* @param[in] ckst_en Enable clock-stretching by peripherals when 1.
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**************************************************************************/
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**************************************************************************/
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void neorv32_twi_setup(uint8_t prsc, uint8_t ckst_en) {
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void neorv32_twi_setup(uint8_t prsc, uint8_t ckst_en) {
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TWI_CT = 0; // reset
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NEORV32_TWI.CTRL = 0; // reset
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uint32_t ct_enable = 1;
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uint32_t ct_enable = 1;
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ct_enable = ct_enable << TWI_CT_EN;
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ct_enable = ct_enable << TWI_CTRL_EN;
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uint32_t ct_prsc = (uint32_t)(prsc & 0x07);
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uint32_t ct_prsc = (uint32_t)(prsc & 0x07);
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ct_prsc = ct_prsc << TWI_CT_PRSC0;
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ct_prsc = ct_prsc << TWI_CTRL_PRSC0;
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uint32_t ct_cksten = (uint32_t)(ckst_en & 0x01);
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uint32_t ct_cksten = (uint32_t)(ckst_en & 0x01);
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ct_cksten = ct_cksten << TWI_CT_CKSTEN;
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ct_cksten = ct_cksten << TWI_CTRL_CKSTEN;
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TWI_CT = ct_enable | ct_prsc | ct_cksten;
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NEORV32_TWI.CTRL = ct_enable | ct_prsc | ct_cksten;
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}
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}
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/**********************************************************************//**
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/**********************************************************************//**
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* Disable TWI controller.
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* Disable TWI controller.
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**************************************************************************/
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**************************************************************************/
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void neorv32_twi_disable(void) {
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void neorv32_twi_disable(void) {
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TWI_CT &= ~((uint32_t)(1 << TWI_CT_EN));
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NEORV32_TWI.CTRL &= ~((uint32_t)(1 << TWI_CTRL_EN));
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}
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}
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/**********************************************************************//**
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/**********************************************************************//**
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* Enable TWI controller.
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* Enable TWI controller.
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**************************************************************************/
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**************************************************************************/
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void neorv32_twi_enable(void) {
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void neorv32_twi_enable(void) {
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TWI_CT |= (uint32_t)(1 << TWI_CT_EN);
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NEORV32_TWI.CTRL |= (uint32_t)(1 << TWI_CTRL_EN);
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}
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}
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/**********************************************************************//**
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/**********************************************************************//**
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* Activate sending ACKs by controller (MACK).
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* Activate sending ACKs by controller (MACK).
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**************************************************************************/
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**************************************************************************/
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void neorv32_twi_mack_enable(void) {
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void neorv32_twi_mack_enable(void) {
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TWI_CT |= ((uint32_t)(1 << TWI_CT_MACK));
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NEORV32_TWI.CTRL |= ((uint32_t)(1 << TWI_CTRL_MACK));
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}
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}
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/**********************************************************************//**
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/**********************************************************************//**
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* Deacivate sending ACKs by controller (MACK).
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* Deacivate sending ACKs by controller (MACK).
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**************************************************************************/
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**************************************************************************/
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void neorv32_twi_mack_disable(void) {
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void neorv32_twi_mack_disable(void) {
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TWI_CT &= ~((uint32_t)(1 << TWI_CT_MACK));
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NEORV32_TWI.CTRL &= ~((uint32_t)(1 << TWI_CTRL_MACK));
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}
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}
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/**********************************************************************//**
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/**********************************************************************//**
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* Check if TWI is busy.
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* Check if TWI is busy.
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*
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*
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* @note This function is blocking.
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* @note This function is blocking.
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*
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*
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* @return 0 if idle, 1 if busy
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* @return 0 if idle, 1 if busy
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**************************************************************************/
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**************************************************************************/
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int neorv32_twi_busy(void) {
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int neorv32_twi_busy(void) {
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if (TWI_CT & (1 << TWI_CT_BUSY)) {
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if (NEORV32_TWI.CTRL & (1 << TWI_CTRL_BUSY)) {
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return 1;
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return 1;
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}
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}
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return 0;
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return 0;
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}
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}
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/**********************************************************************//**
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/**********************************************************************//**
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* Generate START condition and send first byte (address including R/W bit).
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* Generate START condition and send first byte (address including R/W bit).
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*
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*
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* @note Blocking function.
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* @note Blocking function.
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*
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*
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* @param[in] a Data byte including 7-bit address and R/W-bit (lsb).
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* @param[in] a Data byte including 7-bit address and R/W-bit (lsb).
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* @return 0: ACK received, 1: NACK received.
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* @return 0: ACK received, 1: NACK received.
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**************************************************************************/
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**************************************************************************/
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int neorv32_twi_start_trans(uint8_t a) {
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int neorv32_twi_start_trans(uint8_t a) {
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neorv32_twi_generate_start(); // generate START condition
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neorv32_twi_generate_start(); // generate START condition
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TWI_DATA = (uint32_t)a; // send address
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NEORV32_TWI.DATA = (uint32_t)a; // send address
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while(TWI_CT & (1 << TWI_CT_BUSY)); // wait until idle again
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while(NEORV32_TWI.CTRL & (1 << TWI_CTRL_BUSY)); // wait until idle again
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// check for ACK/NACK
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// check for ACK/NACK
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if (TWI_CT & (1 << TWI_CT_ACK))
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if (NEORV32_TWI.CTRL & (1 << TWI_CTRL_ACK))
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return 0; // ACK received
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return 0; // ACK received
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else
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else
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return 1; // NACK received
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return 1; // NACK received
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}
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}
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/**********************************************************************//**
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/**********************************************************************//**
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* Send data byte and also receive data byte (can be read via neorv32_twi_get_data()).
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* Send data byte and also receive data byte (can be read via neorv32_twi_get_data()).
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*
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*
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* @note Blocking function.
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* @note Blocking function.
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*
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*
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* @param[in] d Data byte to be send.
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* @param[in] d Data byte to be send.
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* @return 0: ACK received, 1: NACK received.
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* @return 0: ACK received, 1: NACK received.
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**************************************************************************/
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**************************************************************************/
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int neorv32_twi_trans(uint8_t d) {
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int neorv32_twi_trans(uint8_t d) {
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TWI_DATA = (uint32_t)d; // send data
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NEORV32_TWI.DATA = (uint32_t)d; // send data
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while(TWI_CT & (1 << TWI_CT_BUSY)); // wait until idle again
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while(NEORV32_TWI.CTRL & (1 << TWI_CTRL_BUSY)); // wait until idle again
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// check for ACK/NACK
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// check for ACK/NACK
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if (TWI_CT & (1 << TWI_CT_ACK))
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if (NEORV32_TWI.CTRL & (1 << TWI_CTRL_ACK))
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return 0; // ACK received
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return 0; // ACK received
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else
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else
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return 1; // NACK received
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return 1; // NACK received
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}
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}
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/**********************************************************************//**
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/**********************************************************************//**
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* Get received data from last transmission.
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* Get received data from last transmission.
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*
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*
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* @return 0: Last received data byte.
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* @return 0: Last received data byte.
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**************************************************************************/
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**************************************************************************/
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uint8_t neorv32_twi_get_data(void) {
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uint8_t neorv32_twi_get_data(void) {
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return (uint8_t)TWI_DATA; // get RX data from previous transmission
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return (uint8_t)NEORV32_TWI.DATA; // get RX data from previous transmission
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}
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}
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/**********************************************************************//**
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/**********************************************************************//**
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* Generate STOP condition.
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* Generate STOP condition.
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*
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*
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* @note Blocking function.
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* @note Blocking function.
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**************************************************************************/
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**************************************************************************/
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void neorv32_twi_generate_stop(void) {
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void neorv32_twi_generate_stop(void) {
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TWI_CT |= (uint32_t)(1 << TWI_CT_STOP); // generate STOP condition
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NEORV32_TWI.CTRL |= (uint32_t)(1 << TWI_CTRL_STOP); // generate STOP condition
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while(TWI_CT & (1 << TWI_CT_BUSY)); // wait until idle again
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while(NEORV32_TWI.CTRL & (1 << TWI_CTRL_BUSY)); // wait until idle again
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}
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}
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/**********************************************************************//**
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/**********************************************************************//**
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* Generate START condition.
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* Generate START condition.
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*
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*
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* @note Blocking function.
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* @note Blocking function.
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**************************************************************************/
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**************************************************************************/
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void neorv32_twi_generate_start(void) {
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void neorv32_twi_generate_start(void) {
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TWI_CT |= (1 << TWI_CT_START); // generate START condition
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NEORV32_TWI.CTRL |= (1 << TWI_CTRL_START); // generate START condition
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while(TWI_CT & (1 << TWI_CT_BUSY)); // wait until idle again
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while(NEORV32_TWI.CTRL & (1 << TWI_CTRL_BUSY)); // wait until idle again
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}
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}
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