BitbangI2c Class Reference

#include <i2c_bb.h>

Collaboration diagram for BitbangI2c:

Public Member Functions
bool	init (brain_pin_e scl, brain_pin_e sda)
void	deinit ()
void	write (uint8_t addr, const uint8_t *data, size_t size)
void	read (uint8_t addr, uint8_t *data, size_t size)
void	writeRead (uint8_t addr, const uint8_t *writeData, size_t writeSize, uint8_t *readData, size_t readSize)
uint8_t	readRegister (uint8_t addr, uint8_t reg)
void	writeRegister (uint8_t addr, uint8_t reg, uint8_t val)

Private Member Functions
bool	writeByte (uint8_t data)
uint8_t	readByte (bool ack)
void	sda_low ()
void	sda_high ()
void	scl_low ()
void	scl_high ()
void	start ()
void	stop ()
void	sendBit (bool val)
bool	readBit ()
void	waitQuarterBit ()

Private Attributes
ioportid_t	m_sclPort = 0
ioportmask_t	m_sclPin = 0
ioportid_t	m_sdaPort = 0
ioportmask_t	m_sdaPin = 0

Detailed Description

Definition at line 11 of file i2c_bb.h.

Member Function Documentation

deinit()

void BitbangI2c::deinit

(

)

Definition at line 64 of file i2c_bb.cpp.

                        {
#if EFI_PROD_CODE
    if (m_sclPort) {
        gpio_pin_markUnused(m_sclPort, m_sclPin);
        m_sclPort = NULL;
    }
    if (m_sdaPort) {
        gpio_pin_markUnused(m_sdaPort, m_sdaPin);
        m_sdaPort = NULL;
    }
#endif
}

Referenced by getBoardRevision().

Here is the call graph for this function:

Here is the caller graph for this function:

init()

bool BitbangI2c::init	(	brain_pin_e	scl,
		brain_pin_e	sda
	)

Definition at line 37 of file i2c_bb.cpp.

                                                      {
#if EFI_PROD_CODE
    if (m_sdaPort) {
        return false;
    }
 
    if (!isBrainPinValid(scl) || !isBrainPinValid(sda)) {
        return false;
    }
 
    efiSetPadMode("i2c", scl, PAL_MODE_OUTPUT_OPENDRAIN); //PAL_STM32_OTYPE_OPENDRAIN
    efiSetPadMode("i2c", sda, PAL_MODE_OUTPUT_OPENDRAIN);
 
    m_sclPort = getHwPort("i2c", scl);
    m_sclPin = getHwPin("i2c", scl);
 
    m_sdaPort = getHwPort("i2c", sda);
    m_sdaPin = getHwPin("i2c", sda);
#endif
 
    // Both lines idle high
    scl_high();
    sda_high();
 
    return true;
}

Referenced by getBoardRevision(), Ads1015::init(), Lps25::init(), and setHellen128ETBConfig().

Here is the call graph for this function:

Here is the caller graph for this function:

read()

void BitbangI2c::read	(	uint8_t	addr,
		uint8_t *	data,
		size_t	size
	)

Definition at line 210 of file i2c_bb.cpp.

                                                                      {
    start();
 
    // Address + read
    writeByte(addr << 1 | 1);
 
    for (size_t i = 0; i < readSize - 1; i++) {
        // All but the last byte send ACK to indicate we're still reading
        readData[i] = readByte(true);
    }
 
    // last byte sends NAK to indicate we're done reading
    readData[readSize - 1] = readByte(false);
 
    stop();
}

Referenced by Ads1015::readReg(), setHellen128ETBConfig(), and writeRead().

Here is the call graph for this function:

Here is the caller graph for this function:

readBit()

bool BitbangI2c::readBit ( )

private

Definition at line 122 of file i2c_bb.cpp.

                         {
    waitQuarterBit();
 
    scl_high();
 
    waitQuarterBit();
    waitQuarterBit();
 
#if EFI_PROD_CODE
    // Read just before we set the clock low (ie, as late as possible)
    bool val = palReadPad(m_sdaPort, m_sdaPin);
#else
    bool val = false;
#endif
 
    scl_low();
    waitQuarterBit();
 
    return val;
}

Referenced by readByte(), and writeByte().

Here is the call graph for this function:

Here is the caller graph for this function:

readByte()

uint8_t BitbangI2c::readByte ( bool  ack )

private

Definition at line 163 of file i2c_bb.cpp.

                                     {
    uint8_t result = 0;
 
    // Read in 8 data bits
    for (size_t i = 0; i < 8; i++) {
        result = result << 1;
 
        result |= readBit() ? 1 : 0;
    }
 
    // 0 -> ack
    // 1 -> nack
    sendBit(!ack);
 
    // release SDA
    sda_high();
 
    return result;
}

Referenced by read().

Here is the call graph for this function:

Here is the caller graph for this function:

readRegister()

uint8_t BitbangI2c::readRegister	(	uint8_t	addr,
		uint8_t	reg
	)

Definition at line 227 of file i2c_bb.cpp.

                                                          {
    uint8_t retval;
 
    writeRead(addr, &reg, 1, &retval, 1);
 
    return retval;
}

Referenced by Lps25::init().

Here is the call graph for this function:

Here is the caller graph for this function:

scl_high()

void BitbangI2c::scl_high ( )

private

Definition at line 25 of file i2c_bb.cpp.

                          {
#if EFI_PROD_CODE
    palSetPad(m_sclPort, m_sclPin);
#endif
}

Referenced by init(), readBit(), sendBit(), start(), and stop().

Here is the caller graph for this function:

scl_low()

void BitbangI2c::scl_low ( )

private

Definition at line 31 of file i2c_bb.cpp.

                         {
#if EFI_PROD_CODE
    palClearPad(m_sclPort, m_sclPin);
#endif
}

Referenced by readBit(), sendBit(), start(), and stop().

Here is the caller graph for this function:

sda_high()

void BitbangI2c::sda_high ( )

private

Definition at line 13 of file i2c_bb.cpp.

                          {
#if EFI_PROD_CODE
    palSetPad(m_sdaPort, m_sdaPin);
#endif
}

Referenced by init(), readByte(), sendBit(), start(), stop(), and writeByte().

Here is the caller graph for this function:

sda_low()

void BitbangI2c::sda_low ( )

private

Definition at line 19 of file i2c_bb.cpp.

                         {
#if EFI_PROD_CODE
    palClearPad(m_sdaPort, m_sdaPin);
#endif
}

Referenced by sendBit(), start(), and stop().

Here is the caller graph for this function:

sendBit()

void BitbangI2c::sendBit ( bool  val )

private

Definition at line 102 of file i2c_bb.cpp.

                                 {
    waitQuarterBit();
 
    // Write the bit (write while SCL is low)
    if (val) {
        sda_high();
    } else {
        sda_low();
    }
 
    // Data setup time (~100ns min)
    waitQuarterBit();
 
    // Strobe the clock
    scl_high();
    waitQuarterBit();
    scl_low();
    waitQuarterBit();
}

Referenced by readByte(), and writeByte().

Here is the call graph for this function:

Here is the caller graph for this function:

start()

void BitbangI2c::start ( )

private

Definition at line 77 of file i2c_bb.cpp.

                       {
    // Start with both lines high (bus idle)
    sda_high();
    waitQuarterBit();
    scl_high();
    waitQuarterBit();
 
    // SDA goes low while SCL is high
    sda_low();
    waitQuarterBit();
    scl_low();
    waitQuarterBit();
}

Referenced by read(), and write().

Here is the call graph for this function:

Here is the caller graph for this function:

stop()

void BitbangI2c::stop ( )

private

Definition at line 91 of file i2c_bb.cpp.

                      {
    scl_low();
    waitQuarterBit();
    sda_low();
    waitQuarterBit();
    scl_high();
    waitQuarterBit();
    // SDA goes high while SCL is high
    sda_high();
}

Referenced by read(), and write().

Here is the call graph for this function:

Here is the caller graph for this function:

waitQuarterBit()

void BitbangI2c::waitQuarterBit ( )

private

Definition at line 183 of file i2c_bb.cpp.

                                {
    // This yields a bitrate of about 320khz on a 168MHz F4
    for (size_t i = 0; i < 30; i++) {
        __asm__ volatile ("nop");
    }
}

Referenced by readBit(), sendBit(), start(), and stop().

Here is the caller graph for this function:

write()

void BitbangI2c::write	(	uint8_t	addr,
		const uint8_t *	data,
		size_t	size
	)

Definition at line 190 of file i2c_bb.cpp.

                                                                               {
    start();
 
    // Address + write
    writeByte(addr << 1 | 0);
 
    // Write outbound bytes
    for (size_t i = 0; i < writeSize; i++) {
        writeByte(writeData[i]);
    }
 
    stop();
}

Referenced by getBoardRevision(), Ads1015::readReg(), writeRead(), Ads1015::writeReg(), and writeRegister().

Here is the call graph for this function:

Here is the caller graph for this function:

writeByte()

bool BitbangI2c::writeByte ( uint8_t  data )

private

Definition at line 143 of file i2c_bb.cpp.

                                       {
    // write out 8 data bits
    for (size_t i = 0; i < 8; i++) {
        // Send the MSB
        sendBit((data & 0x80) != 0);
 
        data = data << 1;
    }
    
    // Force a release of the data line so the slave can ACK
    sda_high();
 
    // Read the ack bit
    bool ackBit = readBit();
 
    // 0 -> ack
    // 1 -> nack
    return !ackBit;
}

Referenced by read(), and write().

Here is the call graph for this function:

Here is the caller graph for this function:

writeRead()

void BitbangI2c::writeRead	(	uint8_t	addr,
		const uint8_t *	writeData,
		size_t	writeSize,
		uint8_t *	readData,
		size_t	readSize
	)

Definition at line 204 of file i2c_bb.cpp.

                                                                                                                       {
    write(addr, writeData, writeSize);
 
    read(addr, readData, readSize);
}

Referenced by getBoardRevision(), Lps25::readPressureKpa(), and readRegister().

Here is the call graph for this function:

Here is the caller graph for this function:

writeRegister()

void BitbangI2c::writeRegister	(	uint8_t	addr,
		uint8_t	reg,
		uint8_t	val
	)

Definition at line 235 of file i2c_bb.cpp.

                                                                     {
    uint8_t buf[2];
    buf[0] = reg;
    buf[1] = val;
 
    write(addr, buf, 2);
}

Referenced by Lps25::init().

Here is the call graph for this function:

Here is the caller graph for this function:

Field Documentation

m_sclPin

ioportmask_t BitbangI2c::m_sclPin = 0

private

Definition at line 55 of file i2c_bb.h.

Referenced by deinit(), init(), scl_high(), and scl_low().

m_sclPort

ioportid_t BitbangI2c::m_sclPort = 0

private

Definition at line 54 of file i2c_bb.h.

Referenced by deinit(), init(), scl_high(), and scl_low().

m_sdaPin

ioportmask_t BitbangI2c::m_sdaPin = 0

private

Definition at line 57 of file i2c_bb.h.

Referenced by deinit(), init(), readBit(), sda_high(), and sda_low().

m_sdaPort

ioportid_t BitbangI2c::m_sdaPort = 0

private

Definition at line 56 of file i2c_bb.h.

Referenced by deinit(), init(), readBit(), sda_high(), and sda_low().

---

The documentation for this class was generated from the following files:

• hw_layer/drivers/i2c/i2c_bb.h
• hw_layer/drivers/i2c/i2c_bb.cpp