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neorv32/sw/lib/source/neorv32_twi.c

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// #################################################################################################
// # << NEORV32: neorv32_twi.c - Two-Wire Interface Controller (TWI) HW Driver >> #
// # ********************************************************************************************* #
// # BSD 3-Clause License #
// # #
// # Copyright (c) 2022, 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
* @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_EN = 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_SYSINFO->SOC & (1 << SYSINFO_SOC_IO_TWI)) {
return 1;
}
else {
return 0;
}
}
/**********************************************************************//**
* Enable and configure TWI controller. The TWI control register bits are listed in #NEORV32_TWI_CTRL_enum.
*
* @param[in] prsc Clock prescaler select (0..7). See #NEORV32_CLOCK_PRSC_enum.
* @param[in] cdiv Clock divider (0..15).
* @param[in] csen Allow clock stretching when 1.
**************************************************************************/
void neorv32_twi_setup(int prsc, int cdiv, int csen) {
NEORV32_TWI->CTRL = 0; // reset
uint32_t ctrl = 0;
ctrl |= ((uint32_t)( 1) << TWI_CTRL_EN);
ctrl |= ((uint32_t)(prsc & 0x07) << TWI_CTRL_PRSC0);
ctrl |= ((uint32_t)(cdiv & 0x0F) << TWI_CTRL_CDIV0);
ctrl |= ((uint32_t)(csen & 0x01) << TWI_CTRL_CSEN);
NEORV32_TWI->CTRL = ctrl;
}
/**********************************************************************//**
* Disable TWI controller.
**************************************************************************/
void neorv32_twi_disable(void) {
NEORV32_TWI->CTRL &= ~((uint32_t)(1 << TWI_CTRL_EN));
}
/**********************************************************************//**
* Enable TWI controller.
**************************************************************************/
void neorv32_twi_enable(void) {
NEORV32_TWI->CTRL |= (uint32_t)(1 << TWI_CTRL_EN);
}
/**********************************************************************//**
* Activate sending ACKs by controller (MACK).
**************************************************************************/
void neorv32_twi_mack_enable(void) {
NEORV32_TWI->CTRL |= ((uint32_t)(1 << TWI_CTRL_MACK));
}
/**********************************************************************//**
* Deactivate sending ACKs by controller (MACK).
**************************************************************************/
void neorv32_twi_mack_disable(void) {
NEORV32_TWI->CTRL &= ~((uint32_t)(1 << TWI_CTRL_MACK));
}
/**********************************************************************//**
* Check if TWI is busy.
*
* @return 0 if idle, 1 if busy
**************************************************************************/
int neorv32_twi_busy(void) {
if (NEORV32_TWI->CTRL & (1 << TWI_CTRL_BUSY)) {
return 1;
}
else {
return 0;
}
}
/**********************************************************************//**
* 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
return neorv32_twi_trans(a); // transfer address
}
/**********************************************************************//**
* 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) {
NEORV32_TWI->DATA = (uint32_t)d; // send data
while (NEORV32_TWI->CTRL & (1 << TWI_CTRL_BUSY)); // wait until idle again
// check for ACK/NACK
if (NEORV32_TWI->CTRL & (1 << TWI_CTRL_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)NEORV32_TWI->DATA; // get RX data from previous transmission
}
/**********************************************************************//**
* Generate STOP condition.
*
* @note Blocking function.
**************************************************************************/
void neorv32_twi_generate_stop(void) {
NEORV32_TWI->CTRL |= (uint32_t)(1 << TWI_CTRL_STOP); // generate STOP condition
while (NEORV32_TWI->CTRL & (1 << TWI_CTRL_BUSY)); // wait until idle again
}
/**********************************************************************//**
* Generate START (or REPEATED-START) condition.
*
* @note Blocking function.
**************************************************************************/
void neorv32_twi_generate_start(void) {
NEORV32_TWI->CTRL |= (1 << TWI_CTRL_START); // generate START condition
while (NEORV32_TWI->CTRL & (1 << TWI_CTRL_BUSY)); // wait until idle again
}
/**********************************************************************//**
* Check if the TWI bus is currently claimed by any controller.
*
* @return 0: 0 if bus is not claimed, 1 if bus is claimed.
**************************************************************************/
int neorv32_twi_bus_claimed(void) {
if (NEORV32_TWI->CTRL & (1 << TWI_CTRL_CLAIMED)) {
return 1;
}
else {
return 0;
}
}
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