/**
* @brief Enables a channel de-activation edge notification.
* @pre The PWM unit must have been activated using @p pwmStart().
* @pre The channel must have been activated using @p pwmEnableChannel().
* @note If the notification is already enabled then the call has no effect.
*
* @param[in] pwmp pointer to a @p PWMDriver object
* @param[in] channel PWM channel identifier (0...channels-1)
*
* @api
*/
void pwmEnableChannelNotification(PWMDriver *pwmp, pwmchannel_t channel) {
osalDbgCheck((pwmp != NULL) && (channel < pwmp->channels));
osalSysLock();
osalDbgAssert(pwmp->state == PWM_READY, "not ready");
osalDbgAssert((pwmp->enabled & (1 << channel)) != 0,
"channel not enabled");
osalDbgAssert(pwmp->config->channels[channel].callback != NULL,
"undefined channel callback");
pwmEnableChannelNotificationI(pwmp, channel);
osalSysUnlock();
}
/**
* @brief Read some bites from slave device.
*
* @param[in] owp pointer to the @p onewireDriver object
* @param[out] rxbuf pointer to the buffer for read data
* @param[in] rxbytes amount of data to be received
*/
void onewireRead(onewireDriver *owp, uint8_t *rxbuf, size_t rxbytes) {
PWMDriver *pwmd;
PWMConfig *pwmcfg;
size_t mch, sch;
osalDbgCheck((NULL != owp) && (NULL != rxbuf));
osalDbgCheck((rxbytes > 0) && (rxbytes <= ONEWIRE_MAX_TRANSACTION_LEN));
osalDbgAssert(owp->reg.state == ONEWIRE_READY, "Invalid state");
/* Buffer zeroing. This is important because of driver collects
bits using |= operation.*/
memset(rxbuf, 0, rxbytes);
pwmd = owp->config->pwmd;
pwmcfg = owp->config->pwmcfg;
mch = owp->config->master_channel;
sch = owp->config->sample_channel;
owp->reg.bit = 0;
owp->reg.final_timeslot = false;
owp->buf = rxbuf;
owp->reg.bytes = rxbytes;
pwmcfg->period = ONEWIRE_ZERO_WIDTH + ONEWIRE_RECOVERY_WIDTH;
pwmcfg->callback = NULL;
pwmcfg->channels[mch].callback = NULL;
pwmcfg->channels[mch].mode = owp->config->pwmmode;
pwmcfg->channels[sch].callback = pwm_read_bit_cb;
pwmcfg->channels[sch].mode = PWM_OUTPUT_ACTIVE_LOW;
ow_bus_active(owp);
osalSysLock();
pwmEnableChannelI(pwmd, mch, ONEWIRE_ONE_WIDTH);
pwmEnableChannelI(pwmd, sch, ONEWIRE_SAMPLE_WIDTH);
pwmEnableChannelNotificationI(pwmd, sch);
osalThreadSuspendS(&owp->thread);
osalSysUnlock();
ow_bus_idle(owp);
}
/**
* @brief Generate reset pulse on bus.
*
* @param[in] owp pointer to the @p onewireDriver object
*
* @return Bool flag denoting device presence.
* @retval true There is at least one device on bus.
*/
bool onewireReset(onewireDriver *owp) {
PWMDriver *pwmd;
PWMConfig *pwmcfg;
size_t mch, sch;
osalDbgCheck(NULL != owp);
osalDbgAssert(owp->reg.state == ONEWIRE_READY, "Invalid state");
/* short circuit on bus or any other device transmit data */
if (PAL_LOW == ow_read_bit(owp))
return false;
pwmd = owp->config->pwmd;
pwmcfg = owp->config->pwmcfg;
mch = owp->config->master_channel;
sch = owp->config->sample_channel;
pwmcfg->period = ONEWIRE_RESET_LOW_WIDTH + ONEWIRE_RESET_SAMPLE_WIDTH;
pwmcfg->callback = NULL;
pwmcfg->channels[mch].callback = NULL;
pwmcfg->channels[mch].mode = owp->config->pwmmode;
pwmcfg->channels[sch].callback = pwm_reset_cb;
pwmcfg->channels[sch].mode = PWM_OUTPUT_ACTIVE_LOW;
ow_bus_active(owp);
osalSysLock();
pwmEnableChannelI(pwmd, mch, ONEWIRE_RESET_LOW_WIDTH);
pwmEnableChannelI(pwmd, sch, ONEWIRE_RESET_SAMPLE_WIDTH);
pwmEnableChannelNotificationI(pwmd, sch);
osalThreadSuspendS(&owp->thread);
osalSysUnlock();
ow_bus_idle(owp);
/* wait until slave release bus to discriminate short circuit condition */
osalThreadSleepMicroseconds(500);
return (PAL_HIGH == ow_read_bit(owp)) && (true == owp->reg.slave_present);
}
/**
* @brief Performs tree search on bus.
* @note This function does internal 1-wire reset calls every search
* iteration.
*
* @param[in] owp pointer to a @p OWDriver object
* @param[out] result pointer to buffer for discovered ROMs
* @param[in] max_rom_cnt buffer size in ROMs count for overflow prevention
*
* @return Count of discovered ROMs. May be more than max_rom_cnt.
* @retval 0 no ROMs found or communication error occurred.
*/
size_t onewireSearchRom(onewireDriver *owp, uint8_t *result,
size_t max_rom_cnt) {
PWMDriver *pwmd;
PWMConfig *pwmcfg;
uint8_t cmd;
size_t mch, sch;
osalDbgCheck(NULL != owp);
osalDbgAssert(ONEWIRE_READY == owp->reg.state, "Invalid state");
osalDbgCheck((max_rom_cnt <= 256) && (max_rom_cnt > 0));
pwmd = owp->config->pwmd;
pwmcfg = owp->config->pwmcfg;
cmd = ONEWIRE_CMD_SEARCH_ROM;
mch = owp->config->master_channel;
sch = owp->config->sample_channel;
search_clean_start(&owp->search_rom);
do {
/* every search must be started from reset pulse */
if (false == onewireReset(owp))
return 0;
/* initialize buffer to store result */
if (owp->search_rom.reg.devices_found >= max_rom_cnt)
owp->search_rom.retbuf = result + 8*(max_rom_cnt-1);
else
owp->search_rom.retbuf = result + 8*owp->search_rom.reg.devices_found;
memset(owp->search_rom.retbuf, 0, 8);
/* clean iteration state */
search_clean_iteration(&owp->search_rom);
/**/
onewireWrite(&OWD1, &cmd, 1, 0);
/* Reconfiguration always needed because of previous call onewireWrite.*/
pwmcfg->period = ONEWIRE_ZERO_WIDTH + ONEWIRE_RECOVERY_WIDTH;
pwmcfg->callback = NULL;
pwmcfg->channels[mch].callback = NULL;
pwmcfg->channels[mch].mode = owp->config->pwmmode;
pwmcfg->channels[sch].callback = pwm_search_rom_cb;
pwmcfg->channels[sch].mode = PWM_OUTPUT_ACTIVE_LOW;
ow_bus_active(owp);
osalSysLock();
pwmEnableChannelI(pwmd, mch, ONEWIRE_ONE_WIDTH);
pwmEnableChannelI(pwmd, sch, ONEWIRE_SAMPLE_WIDTH);
pwmEnableChannelNotificationI(pwmd, sch);
osalThreadSuspendS(&owp->thread);
osalSysUnlock();
ow_bus_idle(owp);
if (ONEWIRE_SEARCH_ROM_ERROR != owp->search_rom.reg.result) {
/* check CRC and return 0 (0 == error) if mismatch */
if (owp->search_rom.retbuf[7] != onewireCRC(owp->search_rom.retbuf, 7))
return 0;
/* store cached result for usage in next iteration */
memcpy(owp->search_rom.prev_path, owp->search_rom.retbuf, 8);
}
}
while (ONEWIRE_SEARCH_ROM_SUCCESS == owp->search_rom.reg.result);
/**/
if (ONEWIRE_SEARCH_ROM_ERROR == owp->search_rom.reg.result)
return 0;
else
return owp->search_rom.reg.devices_found;
}
