onewire_master: add parasite power support
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@ -17,8 +17,8 @@
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* @author King Kévin <kingkevin@cuvoodoo.info>
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* @date 2017
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* @note peripherals used: timer @ref onewire_master_timer, GPIO @ref onewire_master_gpio
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* @note overdrive mode is not supported
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* @warning this library does not support active parasite power mode (more than the pull-up resistor itself)
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* @note overdrive mode is not provided
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* @implements 1-Wire protocol description from Book of iButton Standards
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*/
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/* standard libraries */
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@ -44,7 +44,7 @@
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/** @} */
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/** @defgroup onewire_master_gpio GPIO used for 1-wire signal
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* @note use external pull-up resistor on pin
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* @note external pull-up resistor on pin is required (< 5 kOhm)
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* @{
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*/
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#define ONEWIRE_MASTER_PORT A /**< GPIO port */
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@ -63,17 +63,25 @@ volatile enum {
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ONEWIRE_MAX /** to count the number of possible states */
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} onewire_master_state = ONEWIRE_STATE_IDLE;
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volatile bool slave_presence = false; /**< if slaves have been detected */
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uint8_t* buffer = NULL; /**< input/output buffer for read/write commands/functions */
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uint32_t buffer_size = 0; /**< size of buffer in bits */
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volatile uint32_t buffer_bit = 0; /**< number of bits read/written */
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static volatile bool slave_presence = false; /**< if slaves have been detected */
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static uint8_t* buffer = NULL; /**< input/output buffer for read/write commands/functions */
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static uint32_t buffer_size = 0; /**< size of buffer in bits */
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static volatile uint32_t buffer_bit = 0; /**< number of bits read/written */
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static bool onewire_master_parasite = false; /**< if parasite power should be provided whenever the is no communication */
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static uint16_t onewire_master_recovery = 0; /**< the recovery time in us (1 < Trec) */
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void onewire_master_setup(void)
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void onewire_master_setup(bool parasite, uint16_t recovery)
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{
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// setup GPIO with external interrupt
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rcc_periph_clock_enable(RCC_GPIO(ONEWIRE_MASTER_PORT)); // enable clock for GPIO peripheral
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gpio_set_mode(GPIO(ONEWIRE_MASTER_PORT), GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_OPENDRAIN, GPIO(ONEWIRE_MASTER_PIN)); // setup GPIO pin as output (master starts communication before slave replies)
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gpio_set(GPIO(ONEWIRE_MASTER_PORT),GPIO(ONEWIRE_MASTER_PIN)); // idle is high (using pull-up resistor)
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onewire_master_parasite = parasite; // save if we should provide parasite power
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// setup GPIO pin as output (master starts communication before slave replies)
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if (onewire_master_parasite) {
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gpio_set_mode(GPIO(ONEWIRE_MASTER_PORT), GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO(ONEWIRE_MASTER_PIN)); // provide parasite power (external pull-up resistor is still require for communication)
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} else {
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gpio_set_mode(GPIO(ONEWIRE_MASTER_PORT), GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_OPENDRAIN, GPIO(ONEWIRE_MASTER_PIN)); // normal 1-Wire communication (only using external pull-up resistor)
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}
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// setup timer to generate/measure signal timing
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rcc_periph_clock_enable(RCC_TIM(ONEWIRE_MASTER_TIMER)); // enable clock for timer peripheral
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@ -82,10 +90,19 @@ void onewire_master_setup(void)
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timer_set_prescaler(TIM(ONEWIRE_MASTER_TIMER), 1-1); // don't use prescale since this 16 bits timer allows to wait > 480 us used for the reset pulse ( 1/(72E6/1/(2**16))=910us )
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// use comparator to time signal (without using the output), starting at slot start
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timer_set_oc_value(TIM(ONEWIRE_MASTER_TIMER), TIM_OC1, 1*(rcc_ahb_frequency/1000000)-1); // use compare function to time master pulling low (1 < Tlowr < 15)
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timer_set_oc_value(TIM(ONEWIRE_MASTER_TIMER), TIM_OC2, 7*(rcc_ahb_frequency/1000000)-1); // use compare function to read of write (1 < Trw < 15)
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timer_set_oc_value(TIM(ONEWIRE_MASTER_TIMER), TIM_OC1, 1*(rcc_ahb_frequency/1000000)-1); // use compare function to time master pulling low when reading (1 < Tlowr < 15)
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timer_set_oc_value(TIM(ONEWIRE_MASTER_TIMER), TIM_OC2, 7*(rcc_ahb_frequency/1000000)-1); // use compare function to read or write 0 or 1 (1 < Trw < 15)
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timer_set_oc_value(TIM(ONEWIRE_MASTER_TIMER), TIM_OC3, 62*(rcc_ahb_frequency/1000000)-1); // use compare function to end time slot (60 < Tslot < 120), this will be followed by a recovery time (end of timer)
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timer_set_oc_value(TIM(ONEWIRE_MASTER_TIMER), TIM_OC4, 120*(rcc_ahb_frequency/1000000)-1); // use compare function to detect slave presence (60 < Tpdl < 240)
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timer_set_oc_value(TIM(ONEWIRE_MASTER_TIMER), TIM_OC4, (70-10)*(rcc_ahb_frequency/1000000)-1); // use compare function to detect slave presence (15 < Tpdh < 60 + 60 < Tpdl < 240), with hand tunig
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onewire_master_recovery = 5; // set minimum recovery time
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if (recovery>onewire_master_recovery) {
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onewire_master_recovery = recovery; // save desired recovery time
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}
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if (UINT16_MAX/onewire_master_recovery<(rcc_ahb_frequency/1000000)) { // catch integer overflow
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onewire_master_recovery = UINT16_MAX; // save maximum value
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} else {
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onewire_master_recovery *= (rcc_ahb_frequency/1000000); // save actual recovery time value
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}
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timer_clear_flag(TIM(ONEWIRE_MASTER_TIMER), TIM_SR_UIF); // clear update (overflow) flag
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timer_update_on_overflow(TIM(ONEWIRE_MASTER_TIMER)); // only use counter overflow as UEV source (use overflow as start time or timeout)
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@ -101,12 +118,13 @@ bool onewire_master_reset(void)
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// prepare timer
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timer_disable_counter(TIM(ONEWIRE_MASTER_TIMER)); // disable timer to reconfigure it
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timer_set_counter(TIM(ONEWIRE_MASTER_TIMER),0); // reset counter
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timer_set_period(TIM(ONEWIRE_MASTER_TIMER), 490*(rcc_ahb_frequency/1000000)-1); // set timeout to > 480 us
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timer_set_period(TIM(ONEWIRE_MASTER_TIMER), 490*(rcc_ahb_frequency/1000000)-1); // set timeout to > 480 us (480 < Trst)
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slave_presence = false; // reset state
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onewire_master_state = ONEWIRE_STATE_MASTER_RESET; // set new state
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gpio_clear(GPIO(ONEWIRE_MASTER_PORT),GPIO(ONEWIRE_MASTER_PIN)); // pull signal low to start reset (it's not important if it was low in the first place since the reset pulse has no maximum time)
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gpio_set_mode(GPIO(ONEWIRE_MASTER_PORT), GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_OPENDRAIN, GPIO(ONEWIRE_MASTER_PIN)); // normal 1-Wire communication (only using external pull-up resistor)
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gpio_clear(GPIO(ONEWIRE_MASTER_PORT),GPIO(ONEWIRE_MASTER_PIN)); // pull signal low to start reset (it's not important if it was low in the first place since the reset pulse has no maximum time)
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timer_enable_counter(TIM(ONEWIRE_MASTER_TIMER)); // start timer
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while (onewire_master_state!=ONEWIRE_STATE_DONE && onewire_master_state!=ONEWIRE_STATE_ERROR) { // wait until reset procedure completed
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@ -131,13 +149,20 @@ static bool onewire_master_write(void)
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// prepare timer
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timer_disable_counter(TIM(ONEWIRE_MASTER_TIMER)); // disable timer to reconfigure it
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timer_set_counter(TIM(ONEWIRE_MASTER_TIMER),0); // reset counter
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timer_set_period(TIM(ONEWIRE_MASTER_TIMER), TIM_CCR3(TIM(ONEWIRE_MASTER_TIMER))+5*(rcc_ahb_frequency/1000000)); // set time for new time slot (Trec>1, after time slot end)
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uint16_t timeout = TIM_CCR3(TIM(ONEWIRE_MASTER_TIMER)); // time until new slot (= end of slot+recovery)
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if (UINT16_MAX-timeout<onewire_master_recovery) { // catch integer overflow
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timeout = UINT16_MAX; // set maximum value
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} else {
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timeout += onewire_master_recovery; // add recovery time to end of slot
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}
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timer_set_period(TIM(ONEWIRE_MASTER_TIMER), timeout-1); // set time for new time slot (Trec>1, after time slot end and recovery time)
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timer_clear_flag(TIM(ONEWIRE_MASTER_TIMER), TIM_SR_CC2IF); // clear output compare flag
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timer_enable_irq(TIM(ONEWIRE_MASTER_TIMER), TIM_DIER_CC2IE); // enable compare interrupt for bit setting
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timer_clear_flag(TIM(ONEWIRE_MASTER_TIMER), TIM_SR_CC3IF); // clear output compare flag
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timer_enable_irq(TIM(ONEWIRE_MASTER_TIMER), TIM_DIER_CC3IE); // enable compare interrupt for end of time slow
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// start writing
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gpio_set_mode(GPIO(ONEWIRE_MASTER_PORT), GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_OPENDRAIN, GPIO(ONEWIRE_MASTER_PIN)); // normal 1-Wire communication (only using external pull-up resistor)
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gpio_clear(GPIO(ONEWIRE_MASTER_PORT),GPIO(ONEWIRE_MASTER_PIN)); // pull signal low to start slot
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timer_enable_counter(TIM(ONEWIRE_MASTER_TIMER)); // start timer
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while (onewire_master_state!=ONEWIRE_STATE_DONE && onewire_master_state!=ONEWIRE_STATE_ERROR) { // wait until write procedure completed
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@ -162,7 +187,15 @@ static bool onewire_master_read(void)
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onewire_master_state = ONEWIRE_STATE_MASTER_READ; // set new state
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// prepare timer
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timer_disable_counter(TIM(ONEWIRE_MASTER_TIMER)); // disable timer to reconfigure it
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timer_set_counter(TIM(ONEWIRE_MASTER_TIMER),0); // reset counter
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uint16_t timeout = TIM_CCR3(TIM(ONEWIRE_MASTER_TIMER)); // time until new slot (= end of slot+recovery)
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if (UINT16_MAX-timeout<onewire_master_recovery) { // catch integer overflow
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timeout = UINT16_MAX; // set maximum value
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} else {
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timeout += onewire_master_recovery; // add recovery time to end of slot
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}
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timer_set_period(TIM(ONEWIRE_MASTER_TIMER), timeout-1); // set time for new time slot (Trec>1, after time slot end and recovery time)
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timer_clear_flag(TIM(ONEWIRE_MASTER_TIMER), TIM_SR_CC1IF); // clear output compare flag
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timer_enable_irq(TIM(ONEWIRE_MASTER_TIMER), TIM_DIER_CC1IE); // enable compare interrupt for stop pulling low
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timer_clear_flag(TIM(ONEWIRE_MASTER_TIMER), TIM_SR_CC2IF); // clear output compare flag
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@ -171,6 +204,7 @@ static bool onewire_master_read(void)
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timer_enable_irq(TIM(ONEWIRE_MASTER_TIMER), TIM_DIER_CC3IE); // enable compare interrupt for end of time slow
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// start reading
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gpio_set_mode(GPIO(ONEWIRE_MASTER_PORT), GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_OPENDRAIN, GPIO(ONEWIRE_MASTER_PIN)); // normal 1-Wire communication (only using external pull-up resistor)
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gpio_clear(GPIO(ONEWIRE_MASTER_PORT),GPIO(ONEWIRE_MASTER_PIN)); // pull signal low to start slot
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timer_enable_counter(TIM(ONEWIRE_MASTER_TIMER)); // start timer
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while (onewire_master_state!=ONEWIRE_STATE_DONE && onewire_master_state!=ONEWIRE_STATE_ERROR) { // wait until read procedure completed
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@ -386,13 +420,19 @@ void TIM_ISR(ONEWIRE_MASTER_TIMER)(void)
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break;
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default: // unknown state for this stage
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timer_disable_counter(TIM(ONEWIRE_MASTER_TIMER)); // disable timer
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timer_disable_irq(TIM(ONEWIRE_MASTER_TIMER), TIM_DIER_CC1IE); // disable all compare interrupt
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timer_disable_irq(TIM(ONEWIRE_MASTER_TIMER), TIM_DIER_CC2IE); // disable all compare interrupt
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timer_disable_irq(TIM(ONEWIRE_MASTER_TIMER), TIM_DIER_CC3IE); // disable all compare interrupt
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timer_disable_irq(TIM(ONEWIRE_MASTER_TIMER), TIM_DIER_CC4IE); // disable all compare interrupt
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gpio_set(GPIO(ONEWIRE_MASTER_PORT),GPIO(ONEWIRE_MASTER_PIN)); // pull signal high (idle state)
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onewire_master_state = ONEWIRE_STATE_ERROR; // indicate error
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}
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} else if (timer_get_flag(TIM(ONEWIRE_MASTER_TIMER), TIM_SR_CC1IF)) { // compare event happened for master pull low end
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if (onewire_master_parasite && (ONEWIRE_STATE_ERROR==onewire_master_state || ONEWIRE_STATE_DONE==onewire_master_state)) {
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gpio_set_mode(GPIO(ONEWIRE_MASTER_PORT), GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO(ONEWIRE_MASTER_PIN)); // provide parasite power
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} else {
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gpio_set_mode(GPIO(ONEWIRE_MASTER_PORT), GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_OPENDRAIN, GPIO(ONEWIRE_MASTER_PIN)); // normal 1-Wire communication (only using external pull-up resistor)
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}
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} else if (timer_get_flag(TIM(ONEWIRE_MASTER_TIMER), TIM_SR_CC1IF)) { // compare event happened for master pull low end for read
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timer_clear_flag(TIM(ONEWIRE_MASTER_TIMER), TIM_SR_CC1IF); // clear flag
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switch (onewire_master_state) {
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case ONEWIRE_STATE_MASTER_READ: // master has to read a bit
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@ -433,7 +473,10 @@ void TIM_ISR(ONEWIRE_MASTER_TIMER)(void)
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}
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} else if (timer_get_flag(TIM(ONEWIRE_MASTER_TIMER), TIM_SR_CC3IF)) { // compare event happened for end to time slot
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timer_clear_flag(TIM(ONEWIRE_MASTER_TIMER), TIM_SR_CC3IF); // clear flag
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gpio_set(GPIO(ONEWIRE_MASTER_PORT),GPIO(ONEWIRE_MASTER_PIN)); // pull signal high to end time slot
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gpio_set(GPIO(ONEWIRE_MASTER_PORT),GPIO(ONEWIRE_MASTER_PIN)); // pull signal high to end time slot
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if (onewire_master_parasite) { // provide power during recovery time
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gpio_set_mode(GPIO(ONEWIRE_MASTER_PORT), GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO(ONEWIRE_MASTER_PIN)); // provide parasite power
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}
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} else if (timer_get_flag(TIM(ONEWIRE_MASTER_TIMER), TIM_SR_CC4IF)) { // compare event happened for slave presence detection
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timer_clear_flag(TIM(ONEWIRE_MASTER_TIMER), TIM_SR_CC4IF); // clear flag
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if (gpio_get(GPIO(ONEWIRE_MASTER_PORT),GPIO(ONEWIRE_MASTER_PIN))) { // check is a slave let its presence know by pulling low
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@ -17,13 +17,16 @@
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* @author King Kévin <kingkevin@cuvoodoo.info>
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* @date 2017
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* @note peripherals used: timer @ref onewire_master_timer, GPIO @ref onewire_master_gpio
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* @note overdrive mode is not supported
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* @warning this library does not support active parasite power mode (more than the pull-up resistor itself)
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* @note overdrive mode is not provided
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*/
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#pragma once
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/** setup 1-wire peripheral */
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void onewire_master_setup(void);
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/** setup 1-wire peripheral
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* @param[in] parasite enable parasite power (provide power over 1-Wire line when not communicating)
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* @warning multiple masters and interrupts are prevented when parasite power is used
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* @param[in] recovery recovery time in us between timeslot, e.g. to ensure enough parasite power is provided (0 if not required)
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*/
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void onewire_master_setup(bool parasite, uint16_t recovery);
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/** send reset pulse
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* @return if slaves have indicated their presence
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*/
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