mirror of https://github.com/SMFSW/cI2C
454 lines
14 KiB
C
Executable File
454 lines
14 KiB
C
Executable File
/*!\file ci2c.c
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** \author SMFSW
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** \copyright MIT SMFSW (2017-2018)
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** \brief arduino master i2c in plain c code
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** \warning Don't access (r/w) last 16b internal address byte alone right after init, this would lead to hazardous result (in such case, make a dummy read of addr 0 before)
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**/
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// TODO: add interrupt vector / callback for it operations (if not too messy)
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// TODO: consider interrupts at least for RX when slave (and TX when master)
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#include "ci2c.h"
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#define START 0x08
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#define REPEATED_START 0x10
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#define MT_SLA_ACK 0x18
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#define MT_SLA_NACK 0x20
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#define MT_DATA_ACK 0x28
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#define MT_DATA_NACK 0x30
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#define MR_SLA_ACK 0x40
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#define MR_SLA_NACK 0x48
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#define MR_DATA_ACK 0x50
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#define MR_DATA_NACK 0x58
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#define LOST_ARBTRTN 0x38
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#define TWI_STATUS (TWSR & 0xF8)
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//#define isSetRegBit(r, b) ((r & (1 << b)) != 0)
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//#define isClrRegBit(r, b) ((r & (1 << b)) == 0)
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#define setRegBit(r, b) r |= (1 << b) //!< set bit \b b in register \b r
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#define clrRegBit(r, b) r &= (uint8_t) (~(1 << b)) //!< clear bit \b b in register \b r
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#define invRegBit(r, b) r ^= (1 << b) //!< invert bit \b b in register \b r
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/*!\struct i2c
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** \brief static ci2c bus config and control parameters
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**/
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static struct {
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/*!\struct cfg
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** \brief ci2c bus parameters
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**/
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struct {
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I2C_SPEED speed; //!< i2c bus speed
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uint8_t retries; //!< i2c message retries when fail
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uint16_t timeout; //!< i2c timeout (ms)
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} cfg;
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uint16_t start_wait; //!< time start waiting for acknowledge
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bool busy; //!< true if already busy (in case of interrupts implementation)
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} i2c = { { (I2C_SPEED) 0, DEF_CI2C_NB_RETRIES, DEF_CI2C_TIMEOUT }, 0, false };
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// Needed prototypes
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static bool I2C_wr(I2C_SLAVE * slave, const uint16_t reg_addr, uint8_t * data, const uint16_t bytes);
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static bool I2C_rd(I2C_SLAVE * slave, const uint16_t reg_addr, uint8_t * data, const uint16_t bytes);
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/*!\brief Init an I2C slave structure for cMI2C communication
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** \param [in] slave - pointer to the I2C slave structure to init
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** \param [in] sl_addr - I2C slave address
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** \param [in] reg_sz - internal register map size
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** \return nothing
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**/
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void I2C_slave_init(I2C_SLAVE * slave, const uint8_t sl_addr, const I2C_INT_SIZE reg_sz)
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{
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(void) I2C_slave_set_addr(slave, sl_addr);
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(void) I2C_slave_set_reg_size(slave, reg_sz);
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I2C_slave_set_rw_func(slave, (ci2c_fct_ptr) I2C_wr, I2C_WRITE);
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I2C_slave_set_rw_func(slave, (ci2c_fct_ptr) I2C_rd, I2C_READ);
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slave->reg_addr = (uint16_t) -1; // To be sure to send address on first access (warning: unless last 16b byte address is accessed alone)
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slave->status = I2C_OK;
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}
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/*!\brief Redirect slave I2C read/write function (if needed for advanced use)
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** \param [in] slave - pointer to the I2C slave structure to init
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** \param [in] func - pointer to read/write function to affect
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** \param [in] rw - 0 = write function, 1 = read function
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** \return nothing
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**/
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void I2C_slave_set_rw_func(I2C_SLAVE * slave, const ci2c_fct_ptr func, const I2C_RW rw)
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{
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ci2c_fct_ptr * pfc = (ci2c_fct_ptr*) (rw ? &slave->cfg.rd : &slave->cfg.wr);
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*pfc = func;
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}
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/*!\brief Change I2C slave address
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** \param [in, out] slave - pointer to the I2C slave structure to init
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** \param [in] sl_addr - I2C slave address
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** \return true if new address set (false if address is >7Fh)
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**/
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bool I2C_slave_set_addr(I2C_SLAVE * slave, const uint8_t sl_addr)
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{
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if (sl_addr > 0x7F) { return false; }
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slave->cfg.addr = sl_addr;
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return true;
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}
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/*!\brief Change I2C registers map size (for access)
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** \param [in, out] slave - pointer to the I2C slave structure
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** \param [in] reg_sz - internal register map size
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** \return true if new size is correct (false otherwise and set to 16bit by default)
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**/
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bool I2C_slave_set_reg_size(I2C_SLAVE * slave, const I2C_INT_SIZE reg_sz)
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{
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slave->cfg.reg_size = reg_sz > I2C_16B_REG ? I2C_16B_REG : reg_sz;
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return !(reg_sz > I2C_16B_REG);
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}
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/*!\brief Set I2C current register address
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** \attribute inline
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** \param [in, out] slave - pointer to the I2C slave structure
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** \param [in] reg_addr - register address
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** \return nothing
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**/
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static inline void __attribute__((__always_inline__)) I2C_slave_set_reg_addr(I2C_SLAVE * slave, const uint16_t reg_addr) {
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slave->reg_addr = reg_addr; }
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/*!\brief Enable I2c module on arduino board (including pull-ups,
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* enabling of ACK, and setting clock frequency)
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** \param [in] speed - I2C bus speed in KHz
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** \return nothing
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**/
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void I2C_init(const uint16_t speed)
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{
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// Set SDA and SCL to ports with pull-ups
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#if defined(__AVR_ATmega168__) || defined(__AVR_ATmega8__) || defined(__AVR_ATmega328P__)
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setRegBit(PORTC, 4);
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setRegBit(PORTC, 5);
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#else
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setRegBit(PORTD, 0);
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setRegBit(PORTD, 1);
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#endif
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(void) I2C_set_speed(speed);
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}
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/*!\brief Disable I2c module on arduino board (releasing pull-ups, and TWI control)
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** \return nothing
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**/
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void I2C_uninit()
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{
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// Release SDA and SCL ports pull-ups
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#if defined(__AVR_ATmega168__) || defined(__AVR_ATmega8__) || defined(__AVR_ATmega328P__)
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clrRegBit(PORTC, 4);
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clrRegBit(PORTC, 5);
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#else
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clrRegBit(PORTD, 0);
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clrRegBit(PORTD, 1);
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#endif
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TWCR = 0;
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}
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/*!\brief I2C bus reset (Release SCL and SDA lines and re-enable module)
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** \return nothing
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**/
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void I2C_reset(void)
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{
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TWCR = 0;
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setRegBit(TWCR, TWEA);
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setRegBit(TWCR, TWEN);
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}
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/*!\brief Change I2C frequency
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** \param [in] speed - I2C speed in KHz (max 400KHz on avr)
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** \return Configured bus speed
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**/
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uint16_t I2C_set_speed(const uint16_t speed)
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{
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i2c.cfg.speed = (I2C_SPEED) ((speed == 0) ? (uint16_t) I2C_STD : ((speed > (uint16_t) I2C_FM) ? (uint16_t) I2C_FM : speed));
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clrRegBit(TWCR, TWEN); // Ensure i2c module is disabled
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// Set prescaler and clock frequency
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clrRegBit(TWSR, TWPS0);
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clrRegBit(TWSR, TWPS1);
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TWBR = (((F_CPU / 1000) / i2c.cfg.speed) - 16) / 2;
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I2C_reset(); // re-enable module
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return i2c.cfg.speed;
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}
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/*!\brief Change I2C ack timeout
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** \param [in] timeout - I2C ack timeout (500 ms max)
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** \return Configured timeout
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**/
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uint16_t I2C_set_timeout(const uint16_t timeout)
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{
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static const uint16_t max_timeout = 500;
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i2c.cfg.timeout = (timeout > max_timeout) ? max_timeout : timeout;
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return i2c.cfg.timeout;
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}
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/*!\brief Change I2C message retries (in case of failure)
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** \param [in] retries - I2C number of retries (max of 8)
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** \return Configured number of retries
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**/
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uint8_t I2C_set_retries(const uint8_t retries)
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{
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static const uint16_t max_retries = 8;
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i2c.cfg.retries = (retries > max_retries) ? max_retries : retries;
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return i2c.cfg.retries;
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}
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/*!\brief Get I2C busy status
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** \return true if busy
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**/
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bool I2C_is_busy(void) {
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return i2c.busy; }
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/*!\brief This function reads or writes the provided data to/from the address specified.
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* If anything in the write process is not successful, then it will be repeated
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* up till 3 more times (default). If still not successful, returns NACK
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** \param [in, out] slave - pointer to the I2C slave structure to init
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** \param [in] reg_addr - register address in register map
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** \param [in] data - pointer to the first byte of a block of data to write
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** \param [in] bytes - indicates how many bytes of data to write
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** \param [in] rw - 0 = write, 1 = read operation
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** \return I2C_STATUS status of write attempt
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**/
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static I2C_STATUS I2C_comm(I2C_SLAVE * slave, const uint16_t reg_addr, uint8_t * data, const uint16_t bytes, const I2C_RW rw)
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{
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uint8_t retry = i2c.cfg.retries;
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bool ack = false;
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ci2c_fct_ptr fc = (ci2c_fct_ptr) (rw ? slave->cfg.rd : slave->cfg.wr);
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if (I2C_is_busy()) { return slave->status = I2C_BUSY; }
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i2c.busy = true;
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ack = fc(slave, reg_addr, data, bytes);
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while ((!ack) && (retry != 0)) // If com not successful, retry some more times
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{
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delay(1);
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ack = fc(slave, reg_addr, data, bytes);
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retry--;
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}
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i2c.busy = false;
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return slave->status = ack ? I2C_OK : I2C_NACK;
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}
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/*!\brief This function writes the provided data to the address specified.
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** \param [in, out] slave - pointer to the I2C slave structure
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** \param [in] reg_addr - register address in register map
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** \param [in] data - pointer to the first byte of a block of data to write
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** \param [in] bytes - indicates how many bytes of data to write
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** \return I2C_STATUS status of write attempt
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**/
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I2C_STATUS I2C_write(I2C_SLAVE * slave, const uint16_t reg_addr, uint8_t * data, const uint16_t bytes) {
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return I2C_comm(slave, reg_addr, data, bytes, I2C_WRITE); }
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/*!\brief This function reads data from the address specified and stores this
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* data in the area provided by the pointer.
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** \param [in, out] slave - pointer to the I2C slave structure
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** \param [in] reg_addr - register address in register map
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** \param [in, out] data - pointer to the first byte of a block of data to read
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** \param [in] bytes - indicates how many bytes of data to read
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** \return I2C_STATUS status of read attempt
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**/
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I2C_STATUS I2C_read(I2C_SLAVE * slave, const uint16_t reg_addr, uint8_t * data, const uint16_t bytes) {
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return I2C_comm(slave, reg_addr, data, bytes, I2C_READ); }
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/*!\brief Start i2c_timeout timer
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** \attribute inline
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** \return nothing
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**/
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static inline void __attribute__((__always_inline__)) I2C_start_timeout(void) {
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i2c.start_wait = (uint16_t) millis(); }
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/*!\brief Test i2c_timeout
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** \attribute inline
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** \return true if i2c_timeout occured (false otherwise)
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**/
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static inline uint8_t __attribute__((__always_inline__)) I2C_timeout(void) {
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return (((uint16_t) millis() - i2c.start_wait) >= i2c.cfg.timeout); }
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/*!\brief Send start condition
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** \return true if start condition acknowledged (false otherwise)
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**/
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bool I2C_start(void)
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{
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I2C_start_timeout();
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TWCR = (1 << TWINT) | (1 << TWSTA) | (1 << TWEN);
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while (!(TWCR & (1 << TWINT)))
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{ if (I2C_timeout()) { I2C_reset(); return false; } }
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if ((TWI_STATUS == START) || (TWI_STATUS == REPEATED_START)) { return true; }
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if (TWI_STATUS == LOST_ARBTRTN) { I2C_reset(); }
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return false;
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}
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/*!\brief Send stop condition
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** \return true if stop condition acknowledged (false otherwise)
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**/
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bool I2C_stop(void)
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{
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I2C_start_timeout();
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TWCR = (1 << TWINT) | (1 << TWEN) | (1 << TWSTO);
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while ((TWCR & (1 << TWSTO)))
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{ if (I2C_timeout()) { I2C_reset(); return false; } }
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return true;
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}
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/*!\brief Send byte on bus
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** \param [in] dat - data to be sent
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** \return true if data sent acknowledged (false otherwise)
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**/
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bool I2C_wr8(const uint8_t dat)
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{
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TWDR = dat;
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I2C_start_timeout();
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TWCR = (1 << TWINT) | (1 << TWEN);
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while (!(TWCR & (1 << TWINT)))
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{ if (I2C_timeout()) { I2C_reset(); return false; } }
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if (TWI_STATUS == MT_DATA_ACK) { return true; }
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if (TWI_STATUS == MT_DATA_NACK) { I2C_stop(); }
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else { I2C_reset(); }
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return false;
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}
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/*!\brief Receive byte from bus
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** \param [in] ack - true if wait for ack
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** \return true if data reception acknowledged (false otherwise)
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**/
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uint8_t I2C_rd8(const bool ack)
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{
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I2C_start_timeout();
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if (ack) { TWCR = (1 << TWINT) | (1 << TWEN) | (1 << TWEA); }
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else { TWCR = (1 << TWINT) | (1 << TWEN); }
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while (!(TWCR & (1 << TWINT)))
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{ if (I2C_timeout()) { I2C_reset(); return false; } }
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if (TWI_STATUS == LOST_ARBTRTN) { I2C_reset(); return false; }
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return ((((TWI_STATUS == MR_DATA_NACK) && (!ack)) || ((TWI_STATUS == MR_DATA_ACK) && (ack))) ? true : false);
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}
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/*!\brief Send I2C address
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** \param [in] slave - pointer to the I2C slave structure
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** \param [in] rw - read/write transaction
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** \return true if I2C chip address sent acknowledged (false otherwise)
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**/
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bool I2C_sndAddr(I2C_SLAVE * slave, const I2C_RW rw)
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{
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TWDR = (slave->cfg.addr << 1) | rw;
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I2C_start_timeout();
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TWCR = (1 << TWINT) | (1 << TWEN);
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while (!(TWCR & (1 << TWINT)))
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{ if (I2C_timeout()) { I2C_reset(); return false; } }
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if ((TWI_STATUS == MT_SLA_ACK) || (TWI_STATUS == MR_SLA_ACK)) { return true; }
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if ((TWI_STATUS == MT_SLA_NACK) || (TWI_STATUS == MR_SLA_NACK)) { I2C_stop(); }
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else { I2C_reset(); }
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return false;
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}
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/*!\brief This procedure calls appropriate functions to perform a proper send transaction on I2C bus.
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** \param [in, out] slave - pointer to the I2C slave structure
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** \param [in] reg_addr - register address in register map
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** \param [in] data - pointer to the first byte of a block of data to write
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** \param [in] bytes - indicates how many bytes of data to write
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** \return Boolean indicating success/fail of write attempt
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**/
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static bool I2C_wr(I2C_SLAVE * slave, const uint16_t reg_addr, uint8_t * data, const uint16_t bytes)
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{
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if (bytes == 0) { return false; }
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if (I2C_start() == false) { return false; }
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if (I2C_sndAddr(slave, I2C_WRITE) == false) { return false; }
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if ((slave->cfg.reg_size) && (reg_addr != slave->reg_addr)) // Don't send address if writing next
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{
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(void) I2C_slave_set_reg_addr(slave, reg_addr);
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if (slave->cfg.reg_size >= I2C_16B_REG) // if size >2, 16bit address is used
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{
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if (I2C_wr8((uint8_t) (reg_addr >> 8)) == false) { return false; }
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}
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if (I2C_wr8((uint8_t) reg_addr) == false) { return false; }
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}
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for (uint16_t cnt = 0; cnt < bytes; cnt++)
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{
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if (I2C_wr8(*data++) == false) { return false; }
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slave->reg_addr++;
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}
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if (I2C_stop() == false) { return false; }
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return true;
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}
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/*!\brief This procedure calls appropriate functions to perform a proper receive transaction on I2C bus.
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** \param [in, out] slave - pointer to the I2C slave structure
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** \param [in] reg_addr - register address in register map
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** \param [in, out] data - pointer to the first byte of a block of data to read
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** \param [in] bytes - indicates how many bytes of data to read
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** \return Boolean indicating success/fail of read attempt
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**/
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static bool I2C_rd(I2C_SLAVE * slave, const uint16_t reg_addr, uint8_t * data, const uint16_t bytes)
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{
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if (bytes == 0) { return false; }
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if ((slave->cfg.reg_size) && (reg_addr != slave->reg_addr)) // Don't send address if reading next
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{
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(void) I2C_slave_set_reg_addr(slave, reg_addr);
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if (I2C_start() == false) { return false; }
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if (I2C_sndAddr(slave, I2C_WRITE) == false) { return false; }
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if (slave->cfg.reg_size >= I2C_16B_REG) // if size >2, 16bit address is used
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{
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if (I2C_wr8((uint8_t) (reg_addr >> 8)) == false) { return false; }
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}
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if (I2C_wr8((uint8_t) reg_addr) == false) { return false; }
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|
}
|
|
if (I2C_start() == false) { return false; }
|
|
if (I2C_sndAddr(slave, I2C_READ) == false) { return false; }
|
|
|
|
for (uint16_t cnt = 0; cnt < bytes; cnt++)
|
|
{
|
|
if (I2C_rd8((cnt == (bytes - 1)) ? false : true) == false) { return false; }
|
|
*data++ = TWDR;
|
|
slave->reg_addr++;
|
|
}
|
|
|
|
if (I2C_stop() == false) { return false; }
|
|
|
|
return true;
|
|
}
|
|
|