/**
* \internal Sets configurations to module
*
* \param[out] module Pointer to software module structure
* \param[in] config Configuration structure with configurations to set
*
* \return Status of setting configuration.
* \retval STATUS_OK If module was configured correctly
* \retval STATUS_ERR_ALREADY_INITIALIZED If setting other GCLK generator than
* previously set
* \retval STATUS_ERR_BAUDRATE_UNAVAILABLE If given baudrate is not compatible
* with set GCLK frequency
*/
static enum status_code _i2c_master_set_config(
struct i2c_master_module *const module,
const struct i2c_master_config *const config)
{
/* Sanity check arguments. */
Assert(module);
Assert(module->hw);
Assert(config);
/* Temporary variables. */
uint32_t tmp_ctrla;
int32_t tmp_baud;
int32_t tmp_baud_hs;
enum status_code tmp_status_code = STATUS_OK;
SercomI2cm *const i2c_module = &(module->hw->I2CM);
Sercom *const sercom_hw = module->hw;
uint8_t sercom_index = _sercom_get_sercom_inst_index(sercom_hw);
/* Pin configuration */
struct system_pinmux_config pin_conf;
system_pinmux_get_config_defaults(&pin_conf);
uint32_t pad0 = config->pinmux_pad0;
uint32_t pad1 = config->pinmux_pad1;
/* SERCOM PAD0 - SDA */
if (pad0 == PINMUX_DEFAULT) {
pad0 = _sercom_get_default_pad(sercom_hw, 0);
}
pin_conf.mux_position = pad0 & 0xFFFF;
pin_conf.direction = SYSTEM_PINMUX_PIN_DIR_OUTPUT_WITH_READBACK;
system_pinmux_pin_set_config(pad0 >> 16, &pin_conf);
/* SERCOM PAD1 - SCL */
if (pad1 == PINMUX_DEFAULT) {
pad1 = _sercom_get_default_pad(sercom_hw, 1);
}
pin_conf.mux_position = pad1 & 0xFFFF;
pin_conf.direction = SYSTEM_PINMUX_PIN_DIR_OUTPUT_WITH_READBACK;
system_pinmux_pin_set_config(pad1 >> 16, &pin_conf);
/* Save timeout on unknown bus state in software module. */
module->unknown_bus_state_timeout = config->unknown_bus_state_timeout;
/* Save timeout on buffer write. */
module->buffer_timeout = config->buffer_timeout;
/* Set whether module should run in standby. */
if (config->run_in_standby || system_is_debugger_present()) {
tmp_ctrla = SERCOM_I2CM_CTRLA_RUNSTDBY;
} else {
tmp_ctrla = 0;
}
/* Check and set start data hold timeout. */
if (config->start_hold_time != I2C_MASTER_START_HOLD_TIME_DISABLED) {
tmp_ctrla |= config->start_hold_time;
}
/* Check and set transfer speed */
tmp_ctrla |= config->transfer_speed;
/* Check and set SCL low timeout. */
if (config->scl_low_timeout) {
tmp_ctrla |= SERCOM_I2CM_CTRLA_LOWTOUTEN;
}
/* Check and set inactive bus timeout. */
if (config->inactive_timeout != I2C_MASTER_INACTIVE_TIMEOUT_DISABLED) {
tmp_ctrla |= config->inactive_timeout;
}
/* Check and set SCL clock stretch mode. */
if (config->scl_stretch_only_after_ack_bit) {
tmp_ctrla |= SERCOM_I2CM_CTRLA_SCLSM;
}
/* Check and set slave SCL low extend timeout. */
if (config->slave_scl_low_extend_timeout) {
tmp_ctrla |= SERCOM_I2CM_CTRLA_SEXTTOEN;
}
/* Check and set master SCL low extend timeout. */
if (config->master_scl_low_extend_timeout) {
tmp_ctrla |= SERCOM_I2CM_CTRLA_MEXTTOEN;
}
/* Write config to register CTRLA. */
i2c_module->CTRLA.reg |= tmp_ctrla;
/* Set configurations in CTRLB. */
i2c_module->CTRLB.reg = SERCOM_I2CM_CTRLB_SMEN;
/* Find and set baudrate. */
tmp_baud = (int32_t)(div_ceil(
system_gclk_chan_get_hz(SERCOM0_GCLK_ID_CORE + sercom_index),
(2000*(config->baud_rate))) - 5);
/* Check that baudrate is supported at current speed. */
if (tmp_baud > 255 || tmp_baud < 0) {
/* Baud rate not supported. */
tmp_status_code = STATUS_ERR_BAUDRATE_UNAVAILABLE;
} else {
/* Find baudrate for high speed */
tmp_baud_hs = (int32_t)(div_ceil(
system_gclk_chan_get_hz(SERCOM0_GCLK_ID_CORE + sercom_index),
(2000*(config->baud_rate_high_speed))) - 1);
/* Check that baudrate is supported at current speed. */
if (tmp_baud_hs > 255 || tmp_baud_hs < 0) {
/* Baud rate not supported. */
tmp_status_code = STATUS_ERR_BAUDRATE_UNAVAILABLE;
}
}
if (tmp_status_code != STATUS_ERR_BAUDRATE_UNAVAILABLE) {
/* Baud rate acceptable. */
i2c_module->BAUD.reg = SERCOM_I2CM_BAUD_BAUD(tmp_baud) |
SERCOM_I2CM_BAUD_HSBAUD(tmp_baud_hs);
}
return tmp_status_code;
}
void i2c_init(i2c_t dev)
{
uint32_t timeout_counter = 0;
int32_t tmp_baud;
assert(dev < I2C_NUMOF);
/* Initialize mutex */
mutex_init(&locks[dev]);
/* DISABLE I2C MASTER */
_i2c_poweroff(dev);
/* Reset I2C */
bus(dev)->CTRLA.reg = SERCOM_I2CM_CTRLA_SWRST;
while (bus(dev)->SYNCBUSY.reg & SERCOM_I2CM_SYNCBUSY_MASK) {}
/* Turn on power manager for sercom */
sercom_clk_en(bus(dev));
/* I2C using CLK GEN 0 */
sercom_set_gen(bus(dev),i2c_config[dev].gclk_src);
/* Check if module is enabled. */
if (bus(dev)->CTRLA.reg & SERCOM_I2CM_CTRLA_ENABLE) {
DEBUG("STATUS_ERR_DENIED\n");
return;
}
/* Check if reset is in progress. */
if (bus(dev)->CTRLA.reg & SERCOM_I2CM_CTRLA_SWRST) {
DEBUG("STATUS_BUSY\n");
return;
}
/************ SERCOM PAD0 - SDA and SERCOM PAD1 - SCL *************/
gpio_init_mux(i2c_config[dev].sda_pin, i2c_config[dev].mux);
gpio_init_mux(i2c_config[dev].scl_pin, i2c_config[dev].mux);
/* I2C CONFIGURATION */
while (bus(dev)->SYNCBUSY.reg & SERCOM_I2CM_SYNCBUSY_MASK) {}
/* Set sercom module to operate in I2C master mode and run in Standby
if user requests it */
bus(dev)->CTRLA.reg = SERCOM_I2CM_CTRLA_MODE_I2C_MASTER |
((i2c_config[dev].flags & I2C_FLAG_RUN_STANDBY) ?
SERCOM_I2CM_CTRLA_RUNSTDBY : 0);
/* Enable Smart Mode (ACK is sent when DATA.DATA is read) */
bus(dev)->CTRLB.reg = SERCOM_I2CM_CTRLB_SMEN;
/* Find and set baudrate. Read speed configuration. Set transfer
* speed: SERCOM_I2CM_CTRLA_SPEED(0): Standard-mode (Sm) up to 100
* kHz and Fast-mode (Fm) up to 400 kHz */
switch (i2c_config[dev].speed) {
case I2C_SPEED_NORMAL:
case I2C_SPEED_FAST:
bus(dev)->CTRLA.reg |= SERCOM_I2CM_CTRLA_SPEED(0);
break;
case I2C_SPEED_HIGH:
bus(dev)->CTRLA.reg |= SERCOM_I2CM_CTRLA_SPEED(2);
break;
default:
DEBUG("BAD BAUDRATE\n");
return;
}
/* Get the baudrate */
tmp_baud = (int32_t)(((CLOCK_CORECLOCK +
(2 * (i2c_config[dev].speed)) - 1) /
(2 * (i2c_config[dev].speed))) -
(i2c_config[dev].speed == I2C_SPEED_HIGH ? 1 : 5));
/* Ensure baudrate is within limits */
if (tmp_baud < 255 && tmp_baud > 0) {
bus(dev)->BAUD.reg = SERCOM_I2CM_BAUD_BAUD(tmp_baud);
}
/* ENABLE I2C MASTER */
_i2c_poweron(dev);
/* Start timeout if bus state is unknown. */
while ((bus(dev)->STATUS.reg &
SERCOM_I2CM_STATUS_BUSSTATE_Msk) == BUSSTATE_UNKNOWN) {
if (timeout_counter++ >= SAMD21_I2C_TIMEOUT) {
/* Timeout, force bus state to idle. */
bus(dev)->STATUS.reg = BUSSTATE_IDLE;
}
}
}