/* Function to write a byte at a specific address */
bool eeprom_write_byte(uint16_t address, uint8_t data)
{
bool success = true;
/* send START and wait for completion */
i2c_send_start(I2C1);
while ((I2C_SR1(I2C1) & I2C_SR1_SB) == 0);
/* send device address, r/w request and wait for completion */
i2c_send_7bit_address(I2C1, ADDRESS_BYTE, I2C_WRITE);
while ((I2C_SR1(I2C1) & I2C_SR1_ADDR) == 0);
/* check SR2 and go on if OK */
if ((I2C_SR2(I2C1) & I2C_SR2_MSL) /* master mode */
&& (I2C_SR2(I2C1) & I2C_SR2_BUSY)) { /* communication ongoing */
/* send memory address MSB */
i2c_send_data(I2C1, ((uint8_t)(address >> 8)));
while ((I2C_SR1(I2C1) & I2C_SR1_TxE) == 0);
/* send memory address LSB */
i2c_send_data(I2C1, ((uint8_t)address));
while ((I2C_SR1(I2C1) & I2C_SR1_TxE) == 0);
/* send data byte */
i2c_send_data(I2C1, data);
while ((I2C_SR1(I2C1) & I2C_SR1_TxE) == 0);
/* send stop */
i2c_send_stop(I2C1);
/* ATTENTION: consider to wait for a while */
} else {
int tda18219_write_reg(uint8_t reg, uint8_t value)
{
uint32_t __attribute__((unused)) reg32;
/* Send START condition. */
i2c_send_start(I2C1);
/* Waiting for START is send and switched to master mode. */
while (!((I2C_SR1(I2C1) & I2C_SR1_SB)
& (I2C_SR2(I2C1) & (I2C_SR2_MSL | I2C_SR2_BUSY))));
/* Say to what address we want to talk to. */
/* Yes, WRITE is correct - for selecting register in STTS75. */
i2c_send_7bit_address(I2C1, TDA18219_I2C_ADDR, I2C_WRITE);
/* Waiting for address is transferred. */
while (!(I2C_SR1(I2C1) & I2C_SR1_ADDR));
/* Cleaning ADDR condition sequence. */
reg32 = I2C_SR2(I2C1);
i2c_send_data(I2C1, reg);
while (!(I2C_SR1(I2C1) & I2C_SR1_TxE));
i2c_send_data(I2C1, value);
while (!(I2C_SR1(I2C1) & (I2C_SR1_BTF | I2C_SR1_TxE)));
i2c_send_stop(I2C1);
return 0;
}
void stts75_write_config(uint32_t i2c, uint8_t sensor)
{
uint32_t reg32 __attribute__((unused));
/* Send START condition. */
i2c_send_start(i2c);
/* Waiting for START is send and switched to master mode. */
while (!((I2C_SR1(i2c) & I2C_SR1_SB)
& (I2C_SR2(i2c) & (I2C_SR2_MSL | I2C_SR2_BUSY))));
/* Send destination address. */
i2c_send_7bit_address(i2c, sensor, I2C_WRITE);
/* Waiting for address is transferred. */
while (!(I2C_SR1(i2c) & I2C_SR1_ADDR));
/* Cleaning ADDR condition sequence. */
reg32 = I2C_SR2(i2c);
/* Sending the data. */
i2c_send_data(i2c, 0x1); /* stts75 config register */
while (!(I2C_SR1(i2c) & I2C_SR1_BTF)); /* Await ByteTransferedFlag. */
/* Polarity reverse - LED glows if temp is below Tos/Thyst. */
i2c_send_data(i2c, 0x4);
while (!(I2C_SR1(i2c) & (I2C_SR1_BTF | I2C_SR1_TxE)));
/* Send STOP condition. */
i2c_send_stop(i2c);
}
void stts75_write_temp_hyst(uint32_t i2c, uint8_t sensor, uint16_t temp_hyst)
{
uint32_t reg32 __attribute__((unused));
/* Send START condition. */
i2c_send_start(i2c);
/* Waiting for START is send and therefore switched to master mode. */
while (!((I2C_SR1(i2c) & I2C_SR1_SB)
& (I2C_SR2(i2c) & (I2C_SR2_MSL | I2C_SR2_BUSY))));
/* Say to what address we want to talk to. */
i2c_send_7bit_address(i2c, sensor, I2C_WRITE);
/* Waiting for address is transferred. */
while (!(I2C_SR1(i2c) & I2C_SR1_ADDR));
/* Cleaning ADDR condition sequence. */
reg32 = I2C_SR2(i2c);
/* Sending the data. */
i2c_send_data(i2c, 0x2); /* TemperatureHysteresis register */
while (!(I2C_SR1(i2c) & I2C_SR1_BTF));
i2c_send_data(i2c, (uint8_t)(temp_hyst >> 8)); /* MSB */
while (!(I2C_SR1(i2c) & I2C_SR1_BTF));
i2c_send_data(i2c, (uint8_t)(temp_hyst & 0xff00)); /* LSB */
/* After the last byte we have to wait for TxE too. */
while (!(I2C_SR1(i2c) & (I2C_SR1_BTF | I2C_SR1_TxE)));
/* Send STOP condition. */
i2c_send_stop(i2c);
}
static int i2c_write(uint8_t reg, uint8_t val)
{
while ((I2C_SR2(I2C_PORT) & I2C_SR2_BUSY)) {
}
gpio_set(GPIOG, GPIO13);
i2c_send_start(I2C_PORT);
/* Wait for master mode selected */
while (!((I2C_SR1(I2C_PORT) & I2C_SR1_SB)
& (I2C_SR2(I2C_PORT) & (I2C_SR2_MSL | I2C_SR2_BUSY))));
gpio_set(GPIOG, GPIO14);
i2c_send_7bit_address(I2C_PORT, SLAVE_ADDRESS, I2C_WRITE);
/* Waiting for address is transferred. */
while (!(I2C_SR1(I2C_PORT) & I2C_SR1_ADDR));
/* Cleaning ADDR condition sequence. */
uint32_t reg32 = I2C_SR2(I2C_PORT);
(void) reg32; /* unused */
/* Common above here */
/* Sending the data. */
i2c_send_data(I2C_PORT, reg);
while (!(I2C_SR1(I2C_PORT) & (I2C_SR1_BTF)));
i2c_send_data(I2C_PORT, val);
while (!(I2C_SR1(I2C_PORT) & (I2C_SR1_BTF | I2C_SR1_TxE)));
/* Send STOP condition. */
i2c_send_stop(I2C_PORT);
return 0;
}
void stts75_write_temp_os(uint32_t i2c, uint8_t sensor, uint16_t temp_os)
{
uint32_t reg32 __attribute__((unused));
/* Send START condition. */
i2c_send_start(i2c);
/* Waiting for START is send and switched to master mode. */
while (!((I2C_SR1(i2c) & I2C_SR1_SB)
& (I2C_SR2(i2c) & (I2C_SR2_MSL | I2C_SR2_BUSY))));
/* Send destination address. */
i2c_send_7bit_address(i2c, sensor, I2C_WRITE);
/* Waiting for address is transferred. */
while (!(I2C_SR1(i2c) & I2C_SR1_ADDR));
/* Cleaning ADDR condition sequence. */
reg32 = I2C_SR2(i2c);
/* Sending the data. */
i2c_send_data(i2c, 0x3); /* OvertemperatureShutdown register */
while (!(I2C_SR1(i2c) & I2C_SR1_BTF));
i2c_send_data(i2c, (uint8_t)(temp_os >> 8)); /* MSB */
while (!(I2C_SR1(i2c) & I2C_SR1_BTF));
i2c_send_data(i2c, (uint8_t)(temp_os & 0xff00)); /* LSB */
/* After the last byte we have to wait for TxE too. */
while (!(I2C_SR1(i2c) & (I2C_SR1_BTF | I2C_SR1_TxE)));
/* Send STOP condition. */
i2c_send_stop(i2c);
}
static uint32_t i2c_read(uint8_t reg)
{
// while ((I2C_SR2(i2c) & I2C_SR2_BUSY)) {
// }
i2c_send_start(I2C_PORT);
/* Wait for master mode selected */
while (!((I2C_SR1(I2C_PORT) & I2C_SR1_SB)
& (I2C_SR2(I2C_PORT) & (I2C_SR2_MSL | I2C_SR2_BUSY))));
i2c_send_7bit_address(I2C_PORT, SLAVE_ADDRESS, I2C_WRITE);
/* Waiting for address is transferred. */
while (!(I2C_SR1(I2C_PORT) & I2C_SR1_ADDR));
/* Cleaning ADDR condition sequence. */
uint32_t reg32 = I2C_SR2(I2C_PORT);
(void) reg32; /* unused */
/* Common stuff ABOVE HERE */
i2c_send_data(I2C_PORT, reg);
while (!(I2C_SR1(I2C_PORT) & (I2C_SR1_BTF)));
i2c_send_start(I2C_PORT);
/* Wait for master mode selected */
while (!((I2C_SR1(I2C_PORT) & I2C_SR1_SB)
& (I2C_SR2(I2C_PORT) & (I2C_SR2_MSL | I2C_SR2_BUSY))));
i2c_send_7bit_address(I2C_PORT, SLAVE_ADDRESS, I2C_READ);
/* Waiting for address is transferred. */
while (!(I2C_SR1(I2C_PORT) & I2C_SR1_ADDR));
i2c_disable_ack(I2C_PORT);
/* Cleaning ADDR condition sequence. */
reg32 = I2C_SR2(I2C_PORT);
(void) reg32; /* unused */
i2c_send_stop(I2C_PORT);
while (!(I2C_SR1(I2C_PORT) & I2C_SR1_RxNE));
uint32_t result = i2c_get_data(I2C_PORT);
i2c_enable_ack(I2C_PORT);
I2C_SR1(I2C_PORT) &= ~I2C_SR1_AF;
return result;
}
static inline void stmi2c_clear_pending_interrupts(uint32_t i2c)
{
uint16_t SR1 = I2C_SR1(i2c);
// Certainly do not wait for buffer interrupts:
// -------------------------------------------
i2c_disable_interrupt(i2c, I2C_CR2_ITBUFEN); // Disable TXE, RXNE
// Error interrupts are handled separately:
// ---------------------------------------
// Clear Event interrupt conditions:
// --------------------------------
// Start Condition Was Generated
if (BIT_X_IS_SET_IN_REG( I2C_SR1_SB, SR1 ) )
{
// SB: cleared by software when reading SR1 and writing to DR
i2c_send_data(i2c, 0x00);
}
// Address Was Sent
if (BIT_X_IS_SET_IN_REG(I2C_SR1_ADDR, SR1) )
{
// ADDR: Cleared by software when reading SR1 and then SR2
uint16_t SR2 __attribute__ ((unused)) = I2C_SR2(i2c);
}
// Byte Transfer Finished
if (BIT_X_IS_SET_IN_REG(I2C_SR1_BTF, SR1) )
{
// SB: cleared by software when reading SR1 and reading/writing to DR
uint8_t dummy __attribute__ ((unused)) = i2c_get_data(i2c);
i2c_send_data(i2c, 0x00);
}
}
// Doc ID 13902 Rev 11 p 714/1072
// Transfer Sequence Diagram for Master Receiver for N=1
static inline enum STMI2CSubTransactionStatus stmi2c_read1(uint32_t i2c, struct i2c_periph *periph, struct i2c_transaction *trans)
{
uint16_t SR1 = I2C_SR1(i2c);
// Start Condition Was Just Generated
if (BIT_X_IS_SET_IN_REG( I2C_SR1_SB, SR1 ) )
{
i2c_disable_interrupt(i2c, I2C_CR2_ITBUFEN);
i2c_send_data(i2c, trans->slave_addr | 0x01);
// Document the current Status
periph->status = I2CAddrRdSent;
}
// Address Was Sent
else if (BIT_X_IS_SET_IN_REG(I2C_SR1_ADDR, SR1) )
{
// First Clear the ACK bit: after the next byte we do not want new bytes
i2c_nack_current(i2c);
i2c_disable_ack(i2c);
// --- next to steps MUST be executed together to avoid missing the stop
__I2C_REG_CRITICAL_ZONE_START;
// Only after setting ACK, read SR2 to clear the ADDR (next byte will start arriving)
uint16_t SR2 __attribute__ ((unused)) = I2C_SR2(i2c);
// Schedule a Stop
PPRZ_I2C_SEND_STOP(i2c);
__I2C_REG_CRITICAL_ZONE_STOP;
// --- end of critical zone -----------
// Enable the RXNE: it will trigger as soon as the 1 byte is received to get the result
i2c_enable_interrupt(i2c, I2C_CR2_ITBUFEN);
// Document the current Status
periph->status = I2CReadingLastByte;
}
// As soon as there is 1 byte ready to read, we have our byte
else if (BIT_X_IS_SET_IN_REG(I2C_SR1_RxNE, SR1) )
{
i2c_disable_interrupt(i2c, I2C_CR2_ITBUFEN);
trans->buf[0] = I2C_DR(i2c);
// We got all the results (stop condition might still be in progress but this is the last interrupt)
trans->status = I2CTransSuccess;
// Document the current Status:
// -the stop was actually already requested in the previous step
periph->status = I2CStopRequested;
return STMI2C_SubTra_Ready_StopRequested;
}
else // Event Logic Error
{
return STMI2C_SubTra_Error;
}
return STMI2C_SubTra_Busy;
}
static void
com_send_start()
{
/* send start */
i2c_send_start(I2C1);
while (!((I2C_SR1(I2C1) & I2C_SR1_SB)
& (I2C_SR2(I2C1) & (I2C_SR2_MSL | I2C_SR2_BUSY))))
;
/* send address */
i2c_send_7bit_address(I2C1, current_address, I2C_WRITE);
while (!(I2C_SR1(I2C1) & I2C_SR1_ADDR))
;
(void)I2C_SR2(I2C1);
selected = true;
}
void i2c_transmit(const i2c_channel *cp, const uint8_t *data, size_t count)
{
uint32_t base = cp->i_base_address;
if (cp->i_is_master) {
// Send start condition.
I2C_CR1(base) |= I2C_CR1_START;
uint32_t t0 = system_millis;
while (!(I2C_SR1(base) & I2C_SR1_SB)) {
if (system_millis >= t0 + TIMEOUT_MSEC) {
fprintf(stderr, "i2c: timeout on SB\n");
return;
}
}
// Send slave address.
I2C_DR(base) = cp->i_address & ~0x01;
t0 = system_millis;
while (!(I2C_SR1(base) & I2C_SR1_ADDR)) {
if (I2C_SR1(base) & I2C_SR1_AF) {
I2C_CR1(base) |= I2C_CR1_STOP;
I2C_SR1(base) = ~I2C_SR1_AF;
fprintf(stderr,
"i2c @ %ld: ack failure on addr\n",
system_millis / 1000);
return;
}
if (system_millis >= t0 + TIMEOUT_MSEC) {
fprintf(stderr, "i2c: timeout on ADDR\n");
return;
}
}
// Clear ADDR flag by reading SR1 and SR2 registers.
uint16_t unused;
unused = I2C_SR1(base);
unused = I2C_SR2(base);
unused = unused;
// Write each data byte; wait for BTF.
for (size_t i = 0; i < count; i++) {
I2C_DR(base) = data[i];
t0 = system_millis;
while (!(I2C_SR1(base) & I2C_SR1_BTF)) {
if (system_millis >= t0 + TIMEOUT_MSEC) {
fprintf(stderr, "i2c: timeout on BTF\n");
return;
}
}
}
I2C_CR1(base) |= I2C_CR1_STOP;
fprintf(stderr, "i2c @ %lu: transmit complete\n", system_millis / 1000);
} else {
assert(false && "slave transmission not implemented");
}
}
static uint8_t i2c_start(uint32_t i2c, uint8_t address, uint8_t mode)
{
i2c_send_start(i2c);
/* Wait for master mode selected */
while (!((I2C_SR1(i2c) & I2C_SR1_SB)
& (I2C_SR2(i2c) & (I2C_SR2_MSL | I2C_SR2_BUSY))));
i2c_send_7bit_address(i2c, address, mode);
/* Waiting for address is transferred. */
while (!(I2C_SR1(i2c) & I2C_SR1_ADDR));
/* Cleaning ADDR condition sequence. */
uint32_t reg32 = I2C_SR2(i2c);
(void) reg32; /* unused */
return 0;
}
static uint32_t i2c_read(uint32_t i2c, uint8_t address, uint8_t reg)
{
while ((I2C_SR2(i2c) & I2C_SR2_BUSY));
i2c_start(i2c, address, I2C_WRITE);
i2c_send_data(i2c, reg);
while (!(I2C_SR1(i2c) & (I2C_SR1_BTF)));
i2c_start(i2c, address, I2C_READ);
i2c_send_stop(i2c);
while (!(I2C_SR1(i2c) & I2C_SR1_RxNE));
uint32_t result = i2c_get_data(i2c);
I2C_SR1(i2c) &= ~I2C_SR1_AF;
return result;
}
bool_t i2c_idle(struct i2c_periph* periph)
{
// This is actually a difficult function:
// -simply reading the status flags can clear bits and corrupt the transaction
uint32_t i2c = (uint32_t) periph->reg_addr;
#ifdef I2C_DEBUG_LED
#if USE_I2C1
if (periph == &i2c1)
{
return TRUE;
}
#endif
#endif
// First we check if the software thinks it is ready
if (periph->status == I2CIdle)
return ! (BIT_X_IS_SET_IN_REG( I2C_SR2_BUSY, I2C_SR2(i2c) ) );
else
return FALSE;
}
uint16_t stts75_read_temperature(uint32_t i2c, uint8_t sensor)
{
uint32_t reg32 __attribute__((unused));
uint16_t temperature;
/* Send START condition. */
i2c_send_start(i2c);
/* Waiting for START is send and switched to master mode. */
while (!((I2C_SR1(i2c) & I2C_SR1_SB)
& (I2C_SR2(i2c) & (I2C_SR2_MSL | I2C_SR2_BUSY))));
/* Say to what address we want to talk to. */
/* Yes, WRITE is correct - for selecting register in STTS75. */
i2c_send_7bit_address(i2c, sensor, I2C_WRITE);
/* Waiting for address is transferred. */
while (!(I2C_SR1(i2c) & I2C_SR1_ADDR));
/* Cleaning ADDR condition sequence. */
reg32 = I2C_SR2(i2c);
i2c_send_data(i2c, 0x0); /* temperature register */
while (!(I2C_SR1(i2c) & (I2C_SR1_BTF | I2C_SR1_TxE)));
/*
* Now we transferred that we want to ACCESS the temperature register.
* Now we send another START condition (repeated START) and then
* transfer the destination but with flag READ.
*/
/* Send START condition. */
i2c_send_start(i2c);
/* Waiting for START is send and switched to master mode. */
while (!((I2C_SR1(i2c) & I2C_SR1_SB)
& (I2C_SR2(i2c) & (I2C_SR2_MSL | I2C_SR2_BUSY))));
/* Say to what address we want to talk to. */
i2c_send_7bit_address(i2c, sensor, I2C_READ);
/* 2-byte receive is a special case. See datasheet POS bit. */
I2C_CR1(i2c) |= (I2C_CR1_POS | I2C_CR1_ACK);
/* Waiting for address is transferred. */
while (!(I2C_SR1(i2c) & I2C_SR1_ADDR));
/* Cleaning ADDR condition sequence. */
reg32 = I2C_SR2(i2c);
/* Cleaning I2C_SR1_ACK. */
I2C_CR1(i2c) &= ~I2C_CR1_ACK;
/* Now the slave should begin to send us the first byte. Await BTF. */
while (!(I2C_SR1(i2c) & I2C_SR1_BTF));
temperature = (uint16_t)(I2C_DR(i2c) << 8); /* MSB */
/*
* Yes they mean it: we have to generate the STOP condition before
* saving the 1st byte.
*/
I2C_CR1(i2c) |= I2C_CR1_STOP;
temperature |= I2C_DR(i2c); /* LSB */
/* Original state. */
I2C_CR1(i2c) &= ~I2C_CR1_POS;
return temperature;
}
// Doc ID 13902 Rev 11 p 712/1072
// Transfer Sequence Diagram for Master Receiver for N>2
static inline enum STMI2CSubTransactionStatus stmi2c_readmany(uint32_t i2c, struct i2c_periph *periph, struct i2c_transaction *trans)
{
uint16_t SR1 = I2C_SR1(i2c);
// Start Condition Was Just Generated
if (BIT_X_IS_SET_IN_REG( I2C_SR1_SB, SR1 ) )
{
i2c_disable_interrupt(i2c, I2C_CR2_ITBUFEN);
// The first data byte will be acked in read many so the slave knows it should send more
i2c_nack_current(i2c);
i2c_enable_ack(i2c);
// Clear the SB flag
i2c_send_data(i2c, trans->slave_addr | 0x01);
// Document the current Status
periph->status = I2CAddrRdSent;
}
// Address Was Sent
else if (BIT_X_IS_SET_IN_REG(I2C_SR1_ADDR, SR1) )
{
periph->idx_buf = 0;
// Enable RXNE: receive an interrupt any time a byte is available
// only enable if MORE than 3 bytes need to be read
if (periph->idx_buf < (trans->len_r - 3))
{
i2c_enable_interrupt(i2c, I2C_CR2_ITBUFEN);
}
// ACK is still on to get more DATA
// Read SR2 to clear the ADDR (next byte will start arriving)
uint16_t SR2 __attribute__ ((unused)) = I2C_SR2(i2c);
// Document the current Status
periph->status = I2CReadingByte;
}
// one or more bytes are available AND we were interested in Buffer interrupts
else if ( (BIT_X_IS_SET_IN_REG(I2C_SR1_RxNE, SR1) ) && (BIT_X_IS_SET_IN_REG(I2C_CR2_ITBUFEN, I2C_CR2(i2c))) )
{
// read byte until 3 bytes remain to be read (e.g. len_r = 6, -> idx=3 means idx 3,4,5 = 3 remain to be read
if (periph->idx_buf < (trans->len_r - 3))
{
trans->buf[periph->idx_buf] = I2C_DR(i2c);
periph->idx_buf ++;
}
// from : 3bytes -> last byte: do nothing
//
// finally: this was the last byte
else if (periph->idx_buf >= (trans->len_r - 1))
{
i2c_disable_interrupt(i2c, I2C_CR2_ITBUFEN);
// Last Value
trans->buf[periph->idx_buf] = i2c_get_data(i2c);
periph->idx_buf ++;
// We got all the results
trans->status = I2CTransSuccess;
return STMI2C_SubTra_Ready_StopRequested;
}
// Check for end of transaction: start waiting for BTF instead of RXNE
if (periph->idx_buf < (trans->len_r - 3))
{
i2c_enable_interrupt(i2c, I2C_CR2_ITBUFEN);
}
else // idx >= len-3: there are 3 bytes to be read
{
// We want to halt I2C to have sufficient time to clear ACK, so:
// Stop listening to RXNE as it will be triggered infinitely since we did not empty the buffer
// on the next (second in buffer) received byte BTF will be set (buffer full and I2C halted)
i2c_disable_interrupt(i2c, I2C_CR2_ITBUFEN);
}
}
// Buffer is full while this was not a RXNE interrupt
else if (BIT_X_IS_SET_IN_REG(I2C_SR1_BTF, SR1) )
{
// Now the shift register and data register contain data(n-2) and data(n-1)
// And I2C is halted so we have time
// --- Make absolutely sure the next 2 I2C actions are performed with no delay
__I2C_REG_CRITICAL_ZONE_START;
// First we clear the ACK while the SCL is held low by BTF
i2c_disable_ack(i2c);
// Now that ACK is cleared we read one byte: instantly the last byte is being clocked in...
trans->buf[periph->idx_buf] = i2c_get_data(i2c);
periph->idx_buf ++;
// Now the last byte is being clocked. Stop in MUST be set BEFORE the transfer of the last byte is complete
PPRZ_I2C_SEND_STOP(i2c);
__I2C_REG_CRITICAL_ZONE_STOP;
// --- end of critical zone -----------
// Document the current Status
periph->status = I2CStopRequested;
// read the byte2 we had in the buffer (BTF means 2 bytes available)
trans->buf[periph->idx_buf] = i2c_get_data(i2c);
periph->idx_buf ++;
// Ask for an interrupt to read the last byte (which is normally still busy now)
// The last byte will be received with RXNE
i2c_enable_interrupt(i2c, I2C_CR2_ITBUFEN);
}
else // Event Logic Error
{
return STMI2C_SubTra_Error;
}
return STMI2C_SubTra_Busy;
}
// Doc ID 13902 Rev 11 p 713/1072
// Transfer Sequence Diagram for Master Receiver for N=2
static inline enum STMI2CSubTransactionStatus stmi2c_read2(uint32_t i2c, struct i2c_periph *periph, struct i2c_transaction *trans)
{
uint16_t SR1 = I2C_SR1(i2c);
// Start Condition Was Just Generated
if (BIT_X_IS_SET_IN_REG( I2C_SR1_SB, SR1 ) )
{
// according to the datasheet: instantly shedule a NAK on the second received byte:
i2c_disable_interrupt(i2c, I2C_CR2_ITBUFEN);
i2c_enable_ack(i2c);
i2c_nack_next(i2c);
i2c_send_data(i2c, trans->slave_addr | 0x01);
// Document the current Status
periph->status = I2CAddrRdSent;
}
// Address Was Sent
else if (BIT_X_IS_SET_IN_REG(I2C_SR1_ADDR, SR1) )
{
// --- make absolutely sure this command is not delayed too much after the previous:
// --- the NAK bits must be set before the first byte arrived: allow other interrupts here
__I2C_REG_CRITICAL_ZONE_START;
// if transfer of DR was finished already then we will get too many bytes
// BEFORE clearing ACK, read SR2 to clear the ADDR (next byte will start arriving)
// clearing ACK after the byte transfer has already started will NACK the next (2nd)
uint16_t SR2 __attribute__ ((unused)) = I2C_SR2(i2c);
// NOT First Clear the ACK bit but only AFTER clearing ADDR
i2c_disable_ack(i2c);
// Disable the RXNE and wait for BTF
i2c_disable_interrupt(i2c, I2C_CR2_ITBUFEN);
__I2C_REG_CRITICAL_ZONE_STOP;
// --- end of critical zone -----------
// We do not set the RxE but wait for both bytes to arrive using BTF
// Document the current Status
periph->status = I2CReadingByte;
}
// Receive buffer if full, master is halted: BTF
else if (BIT_X_IS_SET_IN_REG(I2C_SR1_BTF, SR1) )
{
// Stop condition MUST be set BEFORE reading the DR
// otherwise since there is new buffer space a new byte will be read
PPRZ_I2C_SEND_STOP(i2c);
// Document the current Status
periph->status = I2CStopRequested;
trans->buf[0] = I2C_DR(i2c);
trans->buf[1] = I2C_DR(i2c);
// We got all the results
trans->status = I2CTransSuccess;
return STMI2C_SubTra_Ready_StopRequested;
}
else // Event Logic Error
{
return STMI2C_SubTra_Error;
}
return STMI2C_SubTra_Busy;
}
int i2c_read(struct i2c_dev *i2c, uint8_t addr, uint8_t *data, uint32_t num) {
if (!i2c || !i2c->ready || i2c->port < 1 || i2c->port > 3 || !data || !num) {
return -1;
}
/* Check for bus error */
if (*I2C_SR1(i2c->port) & I2C_SR1_BERR) {
printk("I2C: Bus error, reseting.\r\n");
/* Clear the error and reset I2C */
*I2C_SR1(i2c->port) &= ~(I2C_SR1_BERR);
if (i2c_reset(i2c)) {
/* Failed to reset */
return -1;
}
}
/* Wait until BUSY is reset and previous transaction STOP is complete */
int count = 10000;
while ((*I2C_SR2(i2c->port) & I2C_SR2_BUSY) || (*I2C_CR1(i2c->port) & I2C_CR1_STOP)) {
if (--count == 0) {
printk("I2C: Stalled, reseting.\r\n");
if (i2c_reset(i2c)) {
/* Failed to reset */
return -1;
}
}
else if (count < 0) {
printk("I2C: Stalled, reset failed, force clearing busy.\r\n");
if (i2c_force_clear_busy(i2c)) {
/* Failed to clear */
return -1;
}
}
}
int total = 0;
*I2C_CR1(i2c->port) |= I2C_CR1_START;
count = 10000;
while (!(*I2C_SR1(i2c->port) & I2C_SR1_SB)) {
if (!count--) {
i2c_stop(i2c->port);
return -1;
}
}
*I2C_DR(i2c->port) = (addr << 1) | 1;
count = 10000;
while (!(*I2C_SR1(i2c->port) & I2C_SR1_ADDR)) {
if (*I2C_SR1(i2c->port) & I2C_SR1_AF || !count--) {
i2c_stop(i2c->port);
return -1;
}
}
uint8_t single_byte = num == 1;
if (!single_byte) {
*I2C_CR1(i2c->port) |= I2C_CR1_ACK;
}
else { /* In single byte receive, never ACK */
*I2C_CR1(i2c->port) &= ~(I2C_CR1_ACK);
}
while (num--) {
count = 10000;
while (!(*I2C_SR2(i2c->port) & I2C_SR2_MSL)) {
if (!count--) {
i2c_stop(i2c->port);
return -1;
}
}
/* In single byte receive, stop after ADDR clear (SR1 and SR2 read) */
if (single_byte) {
i2c_stop(i2c->port);
}
count = 10000;
while (!(*I2C_SR1(i2c->port) & I2C_SR1_RXNE)) {
if (!count--) {
i2c_stop(i2c->port);
return -1;
}
}
*data++ = *I2C_DR(i2c->port);
total++;
/* NACK and STOP after second last receive */
if (num == 1) {
*I2C_CR1(i2c->port) &= ~(I2C_CR1_ACK);
i2c_stop(i2c->port);
}
}
return total;
}
int8_t i2c_write(struct i2c_dev *i2c, uint8_t addr, uint8_t *data, uint32_t num) {
if (!i2c || !i2c->ready || i2c->port < 1 || i2c->port > 3 || !data || !num) {
return -1;
}
/* Check for bus error */
if (*I2C_SR1(i2c->port) & I2C_SR1_BERR) {
printk("I2C: Bus error, reseting.\r\n");
/* Clear the error and reset I2C */
*I2C_SR1(i2c->port) &= ~(I2C_SR1_BERR);
if (i2c_reset(i2c)) {
/* Failed to reset */
return -1;
}
}
/* Wait until BUSY is reset and previous transaction STOP is complete */
int count = 10000;
while ((*I2C_SR2(i2c->port) & I2C_SR2_BUSY) || (*I2C_CR1(i2c->port) & I2C_CR1_STOP)) {
if (--count == 0) {
printk("I2C: Stalled, reseting.\r\n");
if (i2c_reset(i2c)) {
/* Failed to reset */
return -1;
}
}
else if (count < 0) {
printk("I2C: Stalled, reset failed, force clearing busy.\r\n");
if (i2c_force_clear_busy(i2c)) {
/* Failed to clear */
return -1;
}
}
}
*I2C_CR1(i2c->port) |= I2C_CR1_START;
count = 10000;
while (!(*I2C_SR1(i2c->port) & I2C_SR1_SB)) {
if (!count--) {
i2c_stop(i2c->port);
return -1;
}
}
*I2C_DR(i2c->port) = addr << 1;
count = 10000;
while (!(*I2C_SR1(i2c->port) & I2C_SR1_ADDR)) {
if ((*I2C_SR1(i2c->port) & I2C_SR1_AF) || !count--) {
i2c_stop(i2c->port);
return -1;
}
}
count = 10000;
while (!(*I2C_SR2(i2c->port) & I2C_SR2_MSL)) {
if (!count--) {
i2c_stop(i2c->port);
return -1;
}
}
int total = 0;
while (num--) {
/* Make sure shift register is empty */
count = 10000;
while (!(*I2C_SR1(i2c->port) & I2C_SR1_TXE)) {
if (!count--) {
i2c_stop(i2c->port);
return -1;
}
}
*I2C_DR(i2c->port) = *data++;
count = 10000;
while (!(*I2C_SR1(i2c->port) & I2C_SR1_TXE)) {
if (!count--) {
i2c_stop(i2c->port);
return -1;
}
}
total += 1;
}
i2c_stop(i2c->port);
return total;
}
/* On rare occassions, the I2C device will get confused, either because we missed
* a timing requirement, or it is just stupid. Regardless, it holds SDA low waiting
* for some unknown action from the master. This keeps the bus BUSY and prevents
* any further communication. This condition is fixed by manually clocking SCL
* until SDA is released by the slave. As far as it is concerned, we just completed
* a normal transaction. */
static int i2c_force_clear_busy(struct i2c_dev *i2c) {
if (!i2c) {
return -1;
}
int count = 10000;
switch (i2c->port) {
case 1:
/* Set pins to output/input */
gpio_moder(GPIOB, I2C1_SCL, GPIO_MODER_OUT);
gpio_moder(GPIOB, I2C1_SDA, GPIO_MODER_IN);
/* Toggle clock until bus no longer busy */
while (!(*GPIO_IDR(GPIOB) & GPIO_IDR_PIN(I2C1_SDA))) {
if (!count--) {
/* Out of time, perhaps the last ditch effort will save us. */
break;
}
/* Toggle clock */
*GPIO_ODR(GPIOB) ^= GPIO_ODR_PIN(I2C1_SCL);
for (volatile int delay = 100; delay > 0; delay--);
}
gpio_moder(GPIOB, I2C1_SCL, GPIO_MODER_ALT);
gpio_moder(GPIOB, I2C1_SDA, GPIO_MODER_ALT);
for (volatile int delay = 100; delay > 0; delay--);
break;
case 2:
/* Set pins to output/input */
gpio_moder(GPIOB, I2C2_SCL, GPIO_MODER_OUT);
gpio_moder(GPIOB, I2C2_SDA, GPIO_MODER_IN);
/* Toggle clock until SDA raised */
while (!(*GPIO_IDR(GPIOB) & GPIO_IDR_PIN(I2C2_SDA))) {
if (!count--) {
/* Out of time, perhaps the last ditch effort will save us. */
break;
}
/* Toggle clock */
*GPIO_ODR(GPIOB) ^= GPIO_ODR_PIN(I2C2_SCL);
for (volatile int delay = 100; delay > 0; delay--);
}
gpio_moder(GPIOB, I2C2_SCL, GPIO_MODER_ALT);
gpio_moder(GPIOB, I2C2_SDA, GPIO_MODER_ALT);
for (volatile int delay = 100; delay > 0; delay--);
break;
default:
return -1;
}
/* Make sure the peripheral recognizes that the bus is now free */
if (*I2C_SR2(i2c->port) & I2C_SR2_BUSY) {
/* Last ditch effort */
if (i2c_reset(i2c) || (*I2C_SR2(i2c->port) & I2C_SR2_BUSY)) {
/* Failed to reset */
printk("I2C: BUSY flag failed to clear.\r\nI2C: I have tried everything I know :(. At this point, reset is your best option.\r\n");
return -1;
}
}
return 0;
}
// Doc ID 13902 Rev 11 p 710/1072
// Transfer Sequence Diagram for Master Transmitter
static inline enum STMI2CSubTransactionStatus stmi2c_send(uint32_t i2c, struct i2c_periph *periph, struct i2c_transaction *trans)
{
uint16_t SR1 = I2C_SR1(i2c);
// Start Condition Was Just Generated
if (BIT_X_IS_SET_IN_REG( I2C_SR1_SB, SR1 ) )
{
// Disable buffer interrupt
i2c_disable_interrupt(i2c, I2C_CR2_ITBUFEN);
// Send Slave address and wait for ADDR interrupt
i2c_send_data(i2c, trans->slave_addr);
// Document the current Status
periph->status = I2CAddrWrSent;
}
// Address Was Sent
else if (BIT_X_IS_SET_IN_REG(I2C_SR1_ADDR, SR1) )
{
// Now read SR2 to clear the ADDR status Bit
uint16_t SR2 __attribute__ ((unused)) = I2C_SR2(i2c);
// Maybe check we are transmitting (did not loose arbitration for instance)
// if (! BIT_X_IS_SET_IN_REG(I2C_SR2_TRA, SR2)) { }
// update: this should be caught by the ARLO error: so we will not arrive here
// Send First max 2 bytes
i2c_send_data(i2c, trans->buf[0]);
if (trans->len_w > 1)
{
i2c_send_data(i2c, trans->buf[1]);
periph->idx_buf = 2;
}
else
{
periph->idx_buf = 1;
}
// Enable buffer-space available interrupt
// only if there is more to send: wait for TXE, no more to send: wait for BTF
if ( periph->idx_buf < trans->len_w)
i2c_enable_interrupt(i2c, I2C_CR2_ITBUFEN);
// Document the current Status
periph->status = I2CSendingByte;
}
// The buffer is not full anymore AND we were not waiting for BTF
else if ((BIT_X_IS_SET_IN_REG(I2C_SR1_TxE, SR1) ) && (BIT_X_IS_SET_IN_REG(I2C_CR2_ITBUFEN, I2C_CR2(i2c))) )
{
// Send the next byte
i2c_send_data(i2c, trans->buf[periph->idx_buf]);
periph->idx_buf++;
// All bytes Sent? Then wait for BTF instead
if ( periph->idx_buf >= trans->len_w)
{
// Not interested anymore to know the buffer has space left
i2c_disable_interrupt(i2c, I2C_CR2_ITBUFEN);
// Next interrupt will be BTF (or error)
}
}
// BTF: means last byte was sent
else if (BIT_X_IS_SET_IN_REG(I2C_SR1_BTF, SR1) )
{
if (trans->type == I2CTransTx)
{
// Tell the driver we are ready
trans->status = I2CTransSuccess;
}
// Otherwise we still need to do the receiving part
return STMI2C_SubTra_Ready;
}
else // Event Logic Error
{
return STMI2C_SubTra_Error;
}
return STMI2C_SubTra_Busy;
}
void i2c_receive(const i2c_channel *cp, uint8_t *data, size_t count)
{
uint32_t base = cp->i_base_address;
if (cp->i_is_master) {
I2C_CR1(base) |= I2C_CR1_ACK;
// Send start condition.
I2C_CR1(base) |= I2C_CR1_START;
uint32_t t0 = system_millis;
while (!(I2C_SR1(base) & I2C_SR1_SB)) {
if (system_millis >= t0 + TIMEOUT_MSEC) {
fprintf(stderr, "i2c: timeout on SB\n");
printf("SR1 = %#lx\n", I2C_SR1(base));
return;
}
}
// Send slave address.
I2C_DR(base) = cp->i_address | 0x01;
t0 = system_millis;
while (!(I2C_SR1(base) & I2C_SR1_ADDR)) {
if (I2C_SR1(base) & I2C_SR1_AF) {
I2C_CR1(base) |= I2C_CR1_STOP;
I2C_SR1(base) = ~I2C_SR1_AF;
fprintf(stderr,
"i2c @ %ld: ack failure on addr\n",
system_millis / 1000);
return;
}
if (system_millis >= t0 + TIMEOUT_MSEC) {
fprintf(stderr, "i2c: timeout on ADDR\n");
return;
}
}
// Clear ADDR flag by reading SR1 and SR2 registers.
uint16_t unused;
unused = I2C_SR1(base);
unused = I2C_SR2(base);
unused = unused;
// Read each data byte; wait for BTF.
for (size_t i = 0; i < count; i++) {
if (i + 1 == count)
I2C_CR1(base) &= ~I2C_CR1_ACK;
t0 = system_millis;
while (true) {
uint32_t sr1 = I2C_SR1(base);
if (sr1 & (I2C_SR1_OVR | I2C_SR1_BERR)) {
fprintf(stderr, "i2c: receive error\n");
break;
}
if (sr1 & I2C_SR1_RxNE)
break;
if (system_millis >= t0 + TIMEOUT_MSEC) {
fprintf(stderr, "i2c: timeout on receive\n");
}
}
data[i] = I2C_DR(base);
I2C_DR(base) = data[i];
}
printf("%lu: I2C receive complete\n", system_millis / 1000);
} else {
assert(false && "slave reception not implemented");
}
}