自学教程：C++ twi_writeTo函数代码示例

/** Reset the FIFO. * This bit resets the FIFO buffer when set to 1 while FIFO_EN equals 0. This * bit automatically clears to 0 after the reset has been triggered. * @see MPU6050_RA_USER_CTRL * @see MPU6050_USERCTRL_FIFO_RESET_BIT */uint8_t MPU6050::resetFIFO() {  buffer[0] = MPU6050_RA_USER_CTRL;  if (twi_writeTo(devAddr, buffer, 1, true)) return 0xFF;  if (twi_readFrom(devAddr, buffer+1, 1) != 1) return 0xFF;  buffer[1] |= (1 << MPU6050_USERCTRL_FIFO_RESET_BIT);  if (twi_writeTo(devAddr, buffer, 2, true)) return 0xFF;  return 0;}

/* * Function ScI2cMxScrollingHorizontal * Desc     ZT.SC-I2CMx Scrolling Horizontal * Input    addr:ZT.SC-I2CMx Address            lr: Scroll direction            spage: start page            epage: end page            frames: Scroll fram * Output   0 .. success *          1 .. length to long for buffer *          2 .. address send, NACK received *          3 .. data send, NACK received *          4 .. other twi error (lost bus arbitration, bus error, ..) */int ZtLib::ScI2cMxScrollingHorizontal(uint8_t addr, uint8_t lr, uint8_t spage, uint8_t epage,uint8_t frames){    uint8_t buff[9] = {REG_CMD, 0x2E, 0x00, spage, frames, epage, 0x00, 0xFF, 0x2F};    twi_writeTo(addr, buff, 2, 1, 1);    buff[0] = REG_CMD;    buff[1] = lr;    for (int i=0; i<10; i++);    return twi_writeTo(addr, buff, 9, 1, 1);}

////	Originally, 'endTransmission' was an f(void) function.//	It has been modified to take one parameter indicating//	whether or not a STOP should be performed on the bus.//	Calling endTransmission(false) allows a sketch to //	perform a repeated start. ////	WARNING: Nothing in the library keeps track of whether//	the bus tenure has been properly ended with a STOP. It//	is very possible to leave the bus in a hung state if//	no call to endTransmission(true) is made. Some I2C//	devices will behave oddly if they do not see a STOP.//uint8_t TwoWireMaster::endTransmission(uint8_t sendStop){#if ORG_FILE  // transmit buffer (blocking)  int8_t ret = twi_writeTo(txAddress, txBuffer, txBufferLength, 1, sendStop);#else  // ORG_FILE  bool s = twiMstrTransfer((txAddress << 1) | I2C_WRITE, txBuffer,                           txBufferLength, sendStop ? I2C_STOP : I2C_REP_START);   int8_t ret = 0;   if (!s) {     if (twiMstrFailureState() == TWI_MTX_ADR_NACK) {       ret = 2;     }else if (twiMstrFailureState() == TWI_MTX_DATA_NACK) {       ret = 3;     } else {       ret = 4;     }   }#endif  // ORG_FILE  // reset tx buffer iterator vars  txBufferIndex = 0;  txBufferLength = 0;  // indicate that we are done transmitting  transmitting = 0;  return ret;}

// Helper function to write to the accelerometer and interpret the error code, if anyvoid GadgetShield::twiWrite(const void *buf, uint8_t length){  uint8_t code;  code = twi_writeTo(ACC_SLAVE_ADDR, (uint8_t *)buf, length, 1);  errorWrite(code);}

/* * Function Seg8b4a036aDisplayDec * Desc     ZT.SEG8B4A036A Display decimal numeral * Input    addr:ZT.SEG8B4A036A Address            val: Display Val            bitnum:Display Bit Number            dotbit: Dot Display * Output   0 .. success *          1 .. length to long for buffer *          2 .. address send, NACK received *          3 .. data send, NACK received *          4 .. other twi error (lost bus arbitration, bus error, ..) */int ZtLib::Seg8b4a036aDisplayDec(uint8_t addr,unsigned short val, uint8_t bitnum, uint8_t dotbit){  uint8_t i;  uint8_t segnum[5];  if (val>9999) return 0xFF;  segnum[0] = REG_DAT;  segnum[1] = val%10;  segnum[2] = (val%100)/10;  segnum[3] = (val/100)%10;  segnum[4] = val/1000;  for (i=1; i<5; i++)  {      segnum[i] = codetable[segnum[i]];      if (dotbit&0x01)      {          segnum[i] |= 0x80;      }      dotbit >>= 1;  }  if (bitnum==DISP_0BIT)      {segnum[4] = 0;segnum[3] = 0;segnum[2] = 0;segnum[1] = 0;}  else if (bitnum==DISP_1BIT) {segnum[4] = 0;segnum[3] = 0;segnum[2] = 0;}  else if (bitnum==DISP_2BIT) {segnum[4] = 0;segnum[3] = 0;}  else if (bitnum==DISP_3BIT) {segnum[4] = 0;}  else if (bitnum==DISP_AUTO)  {     if (val<10)        {segnum[4] = 0;segnum[3] = 0;segnum[2] = 0;}     else if (val<100)  {segnum[4] = 0;segnum[3] = 0;}     else if (val<1000) {segnum[4] = 0;}  }  return twi_writeTo(addr, segnum, 5, 1, 1);}

uint8_t TwoWire::endTransmission(uint8_t sendStop){  int8_t ret = twi_writeTo(txAddress, txBuffer, txBufferLength, sendStop);  txBufferIndex = 0;  txBufferLength = 0;  transmitting = 0;  return ret;}

int i2c_wr_blk(uint8_t cli_addr, uint8_t *dat, uint8_t len){        if (len > TWI_BUFFER_LENGTH)                return -1;        return twi_writeTo(cli_addr, dat, len, USE_BUSY_WAIT, SEND_STOP_BIT);}

/* * Function ScI2cMxDisplayDot16x16 * Desc     Set ZT.SC-I2CMx Display 16*16 Dot * Input    addr:ZT.SC-I2CMx Address            page:page            column:column            *str:16*16 Dot Data * Output   0 .. success *          1 .. length to long for buffer *          2 .. address send, NACK received *          3 .. data send, NACK received *          4 .. other twi error (lost bus arbitration, bus error, ..) */void ZtLib::ScI2cMxDisplayDot16x16(uint8_t addr, uint8_t page, uint8_t column, unsigned char *str){    uint8_t buff[17];    buff[0] = REG_DAT;    ScI2cMxSetLocation(addr, page, column);    for (int i=0; i<16; i++)    {       buff[i+1] = str[i];    }    twi_writeTo(addr, buff, 17, 1, 1);    ScI2cMxSetLocation(addr, page+1, column);    for (int i=0; i<16; i++)    {       buff[i+1] = str[i+16];    }    twi_writeTo(addr, buff, 17, 1, 1);}

uint8_t RTC_DS1307::isrunning(void) {  twi_buf[0] = 0;  twi_writeTo(DS1307_ADDRESS, 1);  // perform blocking read into buffer  (void)twi_readFrom(DS1307_ADDRESS, 1);  uint8_t ss = twi_buf[0];  return !(ss>>7);}

uint8_t ICACHE_FLASH_ATTR wire_endTransmission(){	int8_t ret;	ret = twi_writeTo(wire_txAddress, wire_txBuffer, wire_txBufferLength, true);	wire_txBufferIndex = 0;	wire_txBufferLength = 0;	wire_transmitting = 0;	return ret;}

int i2c_wr_addr_byte(uint8_t cli_addr, uint8_t reg_addr, uint8_t dat){        uint8_t buf[2];        buf[0] = reg_addr;        buf[1] = dat;        return twi_writeTo(cli_addr, buf, sizeof(buf),                                USE_BUSY_WAIT, SEND_STOP_BIT);}

void pot_write(char channel, char address, unsigned char msg) {  unsigned char buf[2];  unsigned short pot = channel;  if (address == OSCOPE_POT_VALUE && pot < POT_N_CHANNELS) {    buf[0] = addrs[pot].pot_number? POT_CMD_WR1 : POT_CMD_WR0;    buf[1] = msg;    twi_writeTo(addrs[pot].i2c_addr, buf, sizeof(buf), 0);  }}

uint8_t twi_endTransmission() {	// transmit buffer (blocking)	int8_t ret = twi_writeTo(txAddress, txBuffer, txBufferLength, 1, true);	// reset tx buffer iterator vars	txBufferIndex = 0;	txBufferLength = 0;	// indicate that we are done transmitting	transmitting = 0;	return ret;}

int i2c_wr_addr16_byte(uint8_t cli_addr, uint16_t reg_addr, uint8_t dat){        uint8_t buf[3];        buf[0] = (uint8_t)((0xFF00 & reg_addr) >> 8);   /* reg addr MSB */        buf[1] = (uint8_t)(0x00FF & reg_addr);          /* reg addr LSB */        buf[2] = dat;        return twi_writeTo(cli_addr, buf, sizeof(buf),                                USE_BUSY_WAIT, SEND_STOP_BIT);}

void TwoWire::endTransmission(void){  // transmit buffer (blocking)  twi_writeTo(txAddress, txBuffer, txBufferLength, 1);  // reset tx buffer iterator vars  txBufferIndex = 0;  txBufferLength = 0;  // indicate that we are done transmitting  transmitting = 0;}

/* * Function ScI2cMxDisplayArea * Desc     Set ZT.SC-I2CMx Display Area * Input    addr:ZT.SC-I2CMx Address            spage: start page            epage: end page            scolumn: start column            ecolumn: end column            *pt: Data * Output   0 .. success *          1 .. length to long for buffer *          2 .. address send, NACK received *          3 .. data send, NACK received *          4 .. other twi error (lost bus arbitration, bus error, ..) */void ZtLib::ScI2cMxDisplayArea(uint8_t addr, uint8_t spage, uint8_t epage, uint8_t scolumn, uint8_t ecolumn, const char *pt){    uint8_t i = 0;    uint8_t j = 0;    uint8_t h = 0;    uint8_t w = 0;    uint16_t cnt = 0;    uint8_t buff[32];    buff[0] = REG_DAT;    h = epage - spage;    w = ecolumn - scolumn;    while ( j<h )    {        ScI2cMxSetLocation(addr, spage + j, scolumn);        uint8_t p=w;        while(p)        {            if(p>=31)            {                for (int n=0; n<31; n++)                {                    buff[1+n] = pt[cnt++];                }                twi_writeTo(addr, buff, 32, 1, 1);                p -= 31;            }            else            {                int n;                for (n=0; n<p; n++)                {                    buff[1+n] = pt[cnt++];                }                twi_writeTo(addr, buff, n+1, 1, 1);                p -= n;            }        }        j++;    }}

void RTC_DS1307::adjust(const DateTime& dt) {  twi_buf[0] = 0;  twi_buf[1] = bin2bcd(dt.second());  twi_buf[2] = bin2bcd(dt.minute());  twi_buf[3] = bin2bcd(dt.hour());  twi_buf[4] = bin2bcd(0);  twi_buf[5] = bin2bcd(dt.day());  twi_buf[6] = bin2bcd(dt.month());  twi_buf[7] = bin2bcd(dt.year() - 2000);  twi_buf[8] = 0;  twi_writeTo(DS1307_ADDRESS, 9);}

////	Originally, 'endTransmission' was an f(void) function.//	It has been modified to take one parameter indicating//	whether or not a STOP should be performed on the bus.//	Calling endTransmission(false) allows a sketch to //	perform a repeated start. ////	WARNING: Nothing in the library keeps track of whether//	the bus tenure has been properly ended with a STOP. It//	is very possible to leave the bus in a hung state if//	no call to endTransmission(true) is made. Some I2C//	devices will behave oddly if they do not see a STOP.//uint8_t TwoWire::endTransmission(uint8_t sendStop){  if(txBufferLength == 0) return 0;  // transmit buffer (blocking)  int8_t ret = twi_writeTo(txAddress, txBuffer, txBufferLength, 1, sendStop);  // reset tx buffer iterator vars  txBufferIndex = 0;  txBufferLength = 0;  // indicate that we are done transmitting  transmitting = 0;  return ret;}

uint8_t i2c_end_transmission(uint8_t sendStop){	// transmit buffer (blocking)	uint8_t ret = twi_writeTo(txAddress, txBuffer, txBufferLength, 1, sendStop);	// reset buffer vars	txBufferIndex = 0;	txBufferLength = 0;	// set transmission flag	transmitting = 0;	return ret;}

int i2c_wr_addr_blk(uint8_t cli_addr, uint8_t reg_addr,                                                uint8_t *dat, uint8_t len){        uint8_t buf[TWI_BUFFER_LENGTH];        if ((len + 1) > TWI_BUFFER_LENGTH)                return -1;        buf[0] = reg_addr;        memcpy(&buf[1], dat, len);        return twi_writeTo(cli_addr, buf, (len + 1),                                USE_BUSY_WAIT, SEND_STOP_BIT);}

int i2c_rd_addr_byte(uint8_t cli_addr, uint8_t reg_addr, uint8_t *dat){        uint8_t ret;        ret = twi_writeTo(cli_addr, &reg_addr, 1, USE_BUSY_WAIT, SEND_STOP_BIT);        if (ret != 0)                return ret;        ret = twi_readFrom(cli_addr, dat, 1, SEND_STOP_BIT);        if (ret == 0)                return -1;        return 0;}

int i2c_wr_addr16_blk(uint8_t cli_addr, uint16_t reg_addr,                                                uint8_t *dat, uint8_t len){        uint8_t buf[TWI_BUFFER_LENGTH];        if ((len + 2) > TWI_BUFFER_LENGTH)                return -1;        buf[0] = (uint8_t)((0xFF00 & reg_addr) >> 8);   /* reg addr MSB */        buf[1] = (uint8_t)(0x00FF & reg_addr);          /* reg addr LSB */        memcpy(&buf[2], dat, len);        return twi_writeTo(cli_addr, buf, (len + 2),                                USE_BUSY_WAIT, SEND_STOP_BIT);}

int i2c_rd_addr_blk(uint8_t cli_addr, uint8_t reg_addr,                                                uint8_t *dat, uint8_t len){        uint8_t ret;        if (len > TWI_BUFFER_LENGTH)                return -1;        ret = twi_writeTo(cli_addr, &reg_addr, 1, USE_BUSY_WAIT, SEND_STOP_BIT);        if (ret != 0)                return ret;        ret = twi_readFrom(cli_addr, dat, len, SEND_STOP_BIT);        if (ret == 0)                return -1;        return 0;}

int i2c_rd_addr16_byte(uint8_t cli_addr, uint16_t reg_addr, uint8_t *dat){        uint8_t buf[2];        uint8_t ret;        buf[0] = (uint8_t)((0xFF00 & reg_addr) >> 8);   /* reg addr MSB */        buf[1] = (uint8_t)(0x00FF & reg_addr);          /* reg addr LSB */        ret = twi_writeTo(cli_addr, buf, sizeof(buf),                                USE_BUSY_WAIT, SEND_STOP_BIT);        if (ret != 0)                return ret;        ret = twi_readFrom(cli_addr, dat, 1, SEND_STOP_BIT);        if (ret == 0)                return -1;        return 0;}

uint8_t TwoWire::endTransmission(void){	// Secure I2C power management	Wire.secureBegin();		// transmit buffer (blocking)	uint8_t ret = twi_writeTo(txAddress, txBuffer, txBufferLength, 1);	// reset tx buffer iterator vars	txBufferIndex = 0;	txBufferLength = 0;	// indicate that we are done transmitting	transmitting = 0;		// Secure I2C power management	Wire.secureEnd();		return ret;}