// read word from register
// returns true if read was successful, false if failed
bool AP_BattMonitor_SMBus_I2C::read_word(uint8_t reg, uint16_t& data) const
{
// take i2c bus semaphore
if (!_dev->get_semaphore()->take_nonblocking()) {
return false;
}
uint8_t buff[3]; // buffer to hold results
// read three bytes and place in last three bytes of buffer
if (!_dev->read_registers(reg, buff, sizeof(buff))) {
_dev->get_semaphore()->give();
return false;
}
// check PEC
uint8_t pec = get_PEC(BATTMONITOR_SMBUS_I2C_ADDR, reg, true, buff, 2);
if (pec != buff[2]) {
_dev->get_semaphore()->give();
return false;
}
// convert buffer to word
data = (uint16_t)buff[1]<<8 | (uint16_t)buff[0];
// give back i2c semaphore
_dev->get_semaphore()->give();
// return success
return true;
}
// read_block - returns number of characters read if successful, zero if unsuccessful
uint8_t AP_BattMonitor_SMBus_I2C::read_block(uint8_t reg, uint8_t* data, uint8_t max_len, bool append_zero) const
{
uint8_t buff[max_len+2]; // buffer to hold results (2 extra byte returned holding length and PEC)
// take i2c bus semaphore
if (!_dev->get_semaphore()->take_nonblocking()) {
return 0;
}
// read bytes
if (!_dev->read_registers(reg, buff, sizeof(buff))) {
_dev->get_semaphore()->give();
return 0;
}
// give back i2c semaphore
_dev->get_semaphore()->give();
// get length
uint8_t bufflen = buff[0];
// sanity check length returned by smbus
if (bufflen == 0 || bufflen > max_len) {
return 0;
}
// check PEC
uint8_t pec = get_PEC(BATTMONITOR_SMBUS_I2C_ADDR, reg, true, buff, bufflen+1);
if (pec != buff[bufflen+1]) {
return 0;
}
// copy data (excluding PEC)
memcpy(data, &buff[1], bufflen);
// optionally add zero to end
if (append_zero) {
data[bufflen] = '\0';
}
// return success
return bufflen;
}
// read_block - returns number of characters read if successful, zero if unsuccessful
uint8_t AP_BattMonitor_SMBus_Maxell::read_block(uint8_t reg, uint8_t* data, bool append_zero) const
{
// get length
uint8_t bufflen;
// read byte (first byte indicates the number of bytes in the block)
if (!_dev->read_registers(reg, &bufflen, 1)) {
return 0;
}
// sanity check length returned by smbus
if (bufflen == 0 || bufflen > SMBUS_READ_BLOCK_MAXIMUM_TRANSFER) {
return 0;
}
// buffer to hold results (2 extra byte returned holding length and PEC)
const uint8_t read_size = bufflen + 1 + (_pec_supported ? 1 : 0);
uint8_t buff[read_size];
// read bytes
if (!_dev->read_registers(reg, buff, read_size)) {
return 0;
}
// check PEC
if (_pec_supported) {
uint8_t pec = get_PEC(AP_BATTMONITOR_SMBUS_I2C_ADDR, reg, true, buff, bufflen+1);
if (pec != buff[bufflen+1]) {
return 0;
}
}
// copy data (excluding PEC)
memcpy(data, &buff[1], bufflen);
// optionally add zero to end
if (append_zero) {
data[bufflen] = '\0';
}
// return success
return bufflen;
}
uint8_t
BATT_SMBUS::read_block(uint8_t reg, uint8_t *data, uint8_t max_len, bool append_zero)
{
uint8_t buff[max_len + 2]; // buffer to hold results
// read bytes including PEC
int ret = transfer(®, 1, buff, max_len + 2);
// return zero on failure
if (ret != OK) {
return 0;
}
// get length
uint8_t bufflen = buff[0];
// sanity check length returned by smbus
if (bufflen == 0 || bufflen > max_len) {
return 0;
}
// check PEC
uint8_t pec = get_PEC(reg, true, buff, bufflen + 1);
if (pec != buff[bufflen + 1]) {
return 0;
}
// copy data
memcpy(data, &buff[1], bufflen);
// optionally add zero to end
if (append_zero) {
data[bufflen] = '\0';
}
// return success
return bufflen;
}
int
BATT_SMBUS::read_reg(uint8_t reg, uint16_t &val)
{
uint8_t buff[3]; // 2 bytes of data + PEC
// read from register
int ret = transfer(®, 1, buff, 3);
if (ret == OK) {
// check PEC
uint8_t pec = get_PEC(reg, true, buff, 2);
if (pec == buff[2]) {
val = (uint16_t)buff[1] << 8 | (uint16_t)buff[0];
} else {
ret = ENOTTY;
}
}
// return success or failure
return ret;
}
