neorv32_twi.h

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// ================================================================================ //
// The NEORV32 RISC-V Processor - https://github.com/stnolting/neorv32              //
// Copyright (c) NEORV32 contributors.                                              //
// Copyright (c) 2020 - 2025 Stephan Nolting. All rights reserved.                  //
// Licensed under the BSD-3-Clause license, see LICENSE for details.                //
// SPDX-License-Identifier: BSD-3-Clause                                            //
// ================================================================================ //

 
#ifndef NEORV32_TWI_H
#define NEORV32_TWI_H
 
#include <stdint.h>
 
 
/**********************************************************************/
typedef volatile struct __attribute__((packed,aligned(4))) {
  uint32_t CTRL; 
  uint32_t DCMD; 
} neorv32_twi_t;

#define NEORV32_TWI ((neorv32_twi_t*) (NEORV32_TWI_BASE))

enum NEORV32_TWI_CTRL_enum {
  TWI_CTRL_EN        =  0, 
  TWI_CTRL_PRSC0     =  1, 
  TWI_CTRL_PRSC1     =  2, 
  TWI_CTRL_PRSC2     =  3, 
  TWI_CTRL_CDIV0     =  4, 
  TWI_CTRL_CDIV1     =  5, 
  TWI_CTRL_CDIV2     =  6, 
  TWI_CTRL_CDIV3     =  7, 
  TWI_CTRL_CLKSTR    =  8, 
 
  TWI_CTRL_FIFO_LSB  = 15, 
  TWI_CTRL_FIFO_MSB  = 18, 
 
  TWI_CTRL_SENSE_SCL = 27, 
  TWI_CTRL_SENSE_SDA = 28, 
  TWI_CTRL_TX_FULL   = 29, 
  TWI_CTRL_RX_AVAIL  = 30, 
  TWI_CTRL_BUSY      = 31  
};

enum NEORV32_TWI_DCMD_enum {
  TWI_DCMD_LSB    =  0, 
  TWI_DCMD_MSB    =  7, 
  TWI_DCMD_ACK    =  8, 
  TWI_DCMD_CMD_LO =  9, 
  TWI_DCMD_CMD_HI = 10  
};

 
 
/**********************************************************************/
#define TWI_CMD_NOP   (0b00) // no operation
#define TWI_CMD_START (0b01) // generate start condition
#define TWI_CMD_STOP  (0b10) // generate stop condition
#define TWI_CMD_RTX   (0b11) // transmit+receive data byte
 
 
/**********************************************************************/
int  neorv32_twi_available(void);
void neorv32_twi_setup(int prsc, int cdiv, int clkstr);
int  neorv32_twi_get_fifo_depth(void);
void neorv32_twi_disable(void);
void neorv32_twi_enable(void);
 
int  neorv32_twi_sense_scl(void);
int  neorv32_twi_sense_sda(void);
 
int  neorv32_twi_busy(void);
int  neorv32_twi_get(uint8_t *data);
 
int  neorv32_twi_transfer(uint8_t *data, int mack);
void neorv32_twi_generate_stop(void);
void neorv32_twi_generate_start(void);
 
void neorv32_twi_send_nonblocking(uint8_t data, int mack);
void neorv32_twi_generate_stop_nonblocking(void);
void neorv32_twi_generate_start_nonblocking(void);
 
 
#endif // NEORV32_TWI_H