diff --git a/lib/onewire_slave.c b/lib/onewire_slave.c
new file mode 100644
index 0000000..039423b
--- /dev/null
+++ b/lib/onewire_slave.c
@@ -0,0 +1,418 @@
+/* This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see .
+ *
+ */
+/** library for 1-wire protocol as master (code)
+ * @file onewire_slave.c
+ * @author King Kévin
+ * @date 2017
+ * @note peripherals used: GPIO and timer @ref onewire_slave_timer, GPIO @ref onewire_slave_gpio
+ * @note overdrive mode is not supported
+ * @implements 1-Wire protocol description from Book of iButton Standards
+ */
+
+/* standard libraries */
+#include // standard integer types
+#include // boolean type
+#include // NULL definition
+
+/* STM32 (including CM3) libraries */
+#include // Cortex M3 utilities
+#include // interrupt handler
+#include // real-time control clock library
+#include // general purpose input output library
+#include // timer library
+#include // external interrupt library
+
+/* own libraries */
+#include "global.h" // help macros
+#include "onewire_slave.h" // own definitions
+
+/** @defgroup onewire_slave_timer timer used to measure 1-wire signal timing
+ * @{
+ */
+#define ONEWIRE_SLAVE_TIMER 2 /**< timer ID */
+/** @} */
+
+/** @defgroup onewire_slave_gpio GPIO used for 1-wire signal
+ * @warning ensure no same pin number on other parts are used for external interrupts
+ * @note external pull-up resistor on pin is required (< 5 kOhm), generally provided by the master
+ * @{
+ */
+#define ONEWIRE_SLAVE_PORT A /**< GPIO port */
+#define ONEWIRE_SLAVE_PIN 4 /**< GPIO pin */
+/** @} */
+
+/** state of 1-Wire communication */
+static volatile enum {
+ ONEWIRE_STATE_IDLE, /**< no current communication */
+ ONEWIRE_STATE_RESET, /**< reset pulse has been detected */
+ ONEWIRE_STATE_WAIT_PRESENCE, /**< waiting before sending the presence pulse */
+ ONEWIRE_STATE_PULSE_PRESENCE, /**< sending the presence pulse */
+ ONEWIRE_STATE_ROM_COMMAND, /**< slave is reading ROM command bits */
+ ONEWIRE_STATE_ROM_READ, /**< slave is sending ROM code in response to ROM command READ ROM */
+ ONEWIRE_STATE_ROM_MATCH, /**< master is sending ROM code to select slave */
+ ONEWIRE_STATE_ROM_SEARCH_TRUE, /**< master is searching ROM code, slave will send first bit (not negated) */
+ ONEWIRE_STATE_ROM_SEARCH_FALSE, /**< master is searching ROM code, slave will send first bit (not negated) */
+ ONEWIRE_STATE_ROM_SEARCH_SELECT, /**< master is searching ROM code, slave will read selected bit */
+ ONEWIRE_STATE_FUNCTION_COMMAND, /**< slave is reading function command bits */
+ ONEWIRE_STATE_FUNCTION_DATA, /**< waiting for user to provide data to transfer */
+ ONEWIRE_STATE_FUNCTION_READ, /**< slave is reading bits */
+ ONEWIRE_STATE_FUNCTION_WRITE, /**< slave is writing bits */
+ ONEWIRE_MAX /** to count the number of possible states */
+} onewire_slave_state = ONEWIRE_STATE_IDLE;
+
+static uint8_t onewire_slave_rom_code[8] = {0}; /**< slave ROM code */
+
+volatile bool onewire_slave_function_code_received = false;
+volatile uint8_t onewire_slave_function_code = 0;
+volatile bool onewire_slave_transfer_complete = false;
+
+static volatile uint8_t bits_buffer = 0; /**< buffer for the incoming bits (up to one byte) */
+static volatile uint32_t bits_bit = 0; /**< number of incoming bits */
+static volatile uint8_t* onewire_slave_transfer_data = NULL; /**< data to transfer (read or write) */
+static volatile uint32_t onewire_slave_transfer_bits = 0; /**< number of bits to transfer */
+
+/** compute CRC for 1-Wire
+ * @note this CRC-8 uses normal polynomial 0x31, reverse polynomial 0x8C, start value 0x00
+ * @param[in] data bytes on which to calculate CRC checksum on
+ * @param[in] length number of bytes in data
+ * @return computed CRC checksum
+ */
+static uint8_t onewire_slave_crc(uint8_t* data, uint32_t length)
+{
+ if (NULL==data || 0==length) { // check input
+ return 0; // wrong input
+ }
+
+ uint8_t crc = 0x00; // initial value
+ for (uint8_t i=0; i>1)^0x8C; // // shift to the right (for the next bit) and XOR with (reverse) polynomial
+ } else {
+ crc >>= 1; // just shift right (for the next bit)
+ }
+ }
+ }
+ return crc;
+}
+
+void onewire_slave_setup(uint8_t family, uint64_t serial)
+{
+ // save ROM code (LSB first)
+ onewire_slave_rom_code[0] = family;
+ onewire_slave_rom_code[1] = serial >> 40;
+ onewire_slave_rom_code[2] = serial >> 32;
+ onewire_slave_rom_code[3] = serial >> 24;
+ onewire_slave_rom_code[4] = serial >> 16;
+ onewire_slave_rom_code[5] = serial >> 8;
+ onewire_slave_rom_code[6] = serial >> 0;
+ onewire_slave_rom_code[7] = onewire_slave_crc(onewire_slave_rom_code, 7); // calculate CRC
+
+ // setup timer to generate/measure signal timing
+ rcc_periph_clock_enable(RCC_TIM(ONEWIRE_SLAVE_TIMER)); // enable clock for timer peripheral
+ timer_reset(TIM(ONEWIRE_SLAVE_TIMER)); // reset timer state
+ timer_set_mode(TIM(ONEWIRE_SLAVE_TIMER), TIM_CR1_CKD_CK_INT, TIM_CR1_CMS_EDGE, TIM_CR1_DIR_UP); // set timer mode, use undivided timer clock, edge alignment (simple count), and count up
+ timer_set_prescaler(TIM(ONEWIRE_SLAVE_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 )
+
+ // use comparator to time signal (without using the output), starting at slot start
+ timer_set_period(TIM(ONEWIRE_SLAVE_TIMER), 480*(rcc_ahb_frequency/1000000)-1-1300); // minimum time needed for a reset pulse (480 < Trst), plus hand tuning
+ timer_set_oc_mode(TIM(ONEWIRE_SLAVE_TIMER), TIM_OC1, TIM_OCM_FROZEN);
+ timer_set_oc_value(TIM(ONEWIRE_SLAVE_TIMER), TIM_OC1, 16*(rcc_ahb_frequency/1000000)-1); // time to wait before sending the presence pulse, after the rising edge of the reset pulse (15 < Tpdh < 60)
+ timer_set_oc_mode(TIM(ONEWIRE_SLAVE_TIMER), TIM_OC2, TIM_OCM_FROZEN);
+ timer_set_oc_value(TIM(ONEWIRE_SLAVE_TIMER), TIM_OC2, 45*(rcc_ahb_frequency/1000000)-1-350); // time to sample the bit after being set (1 < Tlow1 < 15, 60 < Tslot < 120), or stop sending the bit use compare function to detect slave presence (15 = Trdv + 0 < Trelease < 45), plus hand tuning
+ timer_set_oc_value(TIM(ONEWIRE_SLAVE_TIMER), TIM_OC3, 90*(rcc_ahb_frequency/1000000)-1); // time to stop the presence pulse (60 < Tpdl < 120)
+ timer_set_oc_value(TIM(ONEWIRE_SLAVE_TIMER), TIM_OC4, 121*(rcc_ahb_frequency/1000000)-1); // time end of slot (60 < Tslot < 120)
+ timer_clear_flag(TIM(ONEWIRE_SLAVE_TIMER), TIM_SR_UIF | TIM_SR_CC1IF | TIM_SR_CC2IF | TIM_SR_CC3IF | TIM_SR_CC4IF); // clear all interrupt flags
+ timer_update_on_overflow(TIM(ONEWIRE_SLAVE_TIMER)); // only use counter overflow as UEV source (use overflow as start time or timeout)
+ timer_enable_irq(TIM(ONEWIRE_SLAVE_TIMER), TIM_DIER_UIE); // enable update interrupt for overflow
+ nvic_enable_irq(NVIC_TIM_IRQ(ONEWIRE_SLAVE_TIMER)); // catch interrupt in service routine
+
+ onewire_slave_function_code_received = false; // reset state
+ onewire_slave_state = ONEWIRE_STATE_IDLE; // reset state
+ onewire_slave_transfer_complete = false; // reset state
+
+#define TIMDBG_PORT B
+#define TIMDBG_PIN1 12
+#define TIMDBG_PIN2 13
+#define TIMDBG_PIN3 14
+#define TIMDBG_PIN4 15
+rcc_periph_clock_enable(RCC_GPIO(TIMDBG_PORT));
+gpio_set_mode(GPIO(TIMDBG_PORT), GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO(TIMDBG_PIN1) | GPIO(TIMDBG_PIN2) | GPIO(TIMDBG_PIN3) | GPIO(TIMDBG_PIN4));
+
+ // setup GPIO with external interrupt
+ rcc_periph_clock_enable(RCC_GPIO(ONEWIRE_SLAVE_PORT)); // enable clock for GPIO peripheral
+ gpio_set(GPIO(ONEWIRE_SLAVE_PORT), GPIO(ONEWIRE_SLAVE_PIN)); // idle is high (using pull-up resistor)
+ gpio_set_mode(GPIO(ONEWIRE_SLAVE_PORT), GPIO_MODE_OUTPUT_50_MHZ, GPIO_CNF_OUTPUT_OPENDRAIN, GPIO(ONEWIRE_SLAVE_PIN)); // control output using open drain (this mode also allows to read the input signal)
+ rcc_periph_clock_enable(RCC_AFIO); // enable alternate function clock for external interrupt
+ exti_select_source(EXTI(ONEWIRE_SLAVE_PIN), GPIO(ONEWIRE_SLAVE_PORT)); // mask external interrupt of this pin only for this port
+ exti_set_trigger(EXTI(ONEWIRE_SLAVE_PIN), EXTI_TRIGGER_BOTH); // trigger on signal change
+ exti_enable_request(EXTI(ONEWIRE_SLAVE_PIN)); // enable external interrupt
+ nvic_enable_irq(NVIC_EXTI_IRQ(ONEWIRE_SLAVE_PIN)); // enable interrupt
+}
+
+void onewire_slave_function_read(uint8_t* data, uint32_t bits)
+{
+ if (NULL==data || 0==bits) { // verify input
+ return;
+ }
+ if (onewire_slave_state!=ONEWIRE_STATE_FUNCTION_DATA) { // not in the right state to transfer data
+ return;
+ }
+ onewire_slave_transfer_data = data; // save buffer to write to
+ onewire_slave_transfer_bits = bits; // number of bits to read
+ onewire_slave_transfer_complete = false; // reset state
+ bits_bit = 0; // reset number of bits read
+ onewire_slave_state = ONEWIRE_STATE_FUNCTION_READ; // read data
+}
+
+void onewire_slave_function_write(uint8_t* data, uint32_t bits)
+{
+ if (NULL==data || 0==bits) { // verify input
+ return;
+ }
+ if (onewire_slave_state!=ONEWIRE_STATE_FUNCTION_DATA) { // not in the right state to transfer data
+ return;
+ }
+ onewire_slave_transfer_data = data; // save buffer to read from
+ onewire_slave_transfer_bits = bits; // number of bits to write
+ onewire_slave_transfer_complete = false; // reset state
+ bits_bit = 0; // reset number of bits written
+ bits_buffer = onewire_slave_transfer_data[0]; // prepare byte to write
+ onewire_slave_state = ONEWIRE_STATE_FUNCTION_WRITE; // write data
+}
+
+/** interrupt service routine called when 1-Wire signal changes */
+void EXTI_ISR(ONEWIRE_SLAVE_PIN)(void)
+{
+ exti_reset_request(EXTI(ONEWIRE_SLAVE_PIN)); // reset interrupt
+ if (gpio_get(GPIO(ONEWIRE_SLAVE_PORT), GPIO(ONEWIRE_SLAVE_PIN))) { // it's a rising edge
+ switch (onewire_slave_state) {
+ case ONEWIRE_STATE_RESET: // reset pulse has ended
+ timer_disable_counter(TIM(ONEWIRE_SLAVE_TIMER)); // stop timer for reconfiguration
+ timer_set_counter(TIM(ONEWIRE_SLAVE_TIMER), 0); // reset timer counter
+ timer_clear_flag(TIM(ONEWIRE_SLAVE_TIMER), TIM_SR_CC1IF); // clear flag
+ timer_enable_irq(TIM(ONEWIRE_SLAVE_TIMER), TIM_DIER_CC1IE); // enable compare interrupt for presence pulse
+ timer_enable_counter(TIM(ONEWIRE_SLAVE_TIMER)); // start timer to generate timing
+ onewire_slave_state = ONEWIRE_STATE_WAIT_PRESENCE; // set new stated
+ break;
+ case ONEWIRE_STATE_PULSE_PRESENCE: // we stopped sending the presence pulse
+ onewire_slave_state = ONEWIRE_STATE_ROM_COMMAND; // we now expect a ROM command
+ bits_bit = 0; // reset buffer bit count
+ break; // no need to stop the time, the reset will be checked correctly
+ default: // rising edge is not important is the other cases
+ break; // nothing to do
+ }
+ } else { // it's a falling edge, the beginning of a new signal
+ timer_disable_counter(TIM(ONEWIRE_SLAVE_TIMER)); // stop timer for reconfiguration
+ timer_set_counter(TIM(ONEWIRE_SLAVE_TIMER), 0); // reset timer counter
+ timer_disable_irq(TIM(ONEWIRE_SLAVE_TIMER), TIM_DIER_CC1IE | TIM_DIER_CC2IE | TIM_DIER_CC3IE | TIM_DIER_CC4IE); // disable all timers
+ switch (onewire_slave_state) {
+ case ONEWIRE_STATE_PULSE_PRESENCE: // we started sending the presence pulse
+ timer_enable_irq(TIM(ONEWIRE_SLAVE_TIMER), TIM_DIER_CC3IE); // enable timer for end of pulse
+ break;
+ case ONEWIRE_STATE_ROM_COMMAND: // read ROM command bits
+ case ONEWIRE_STATE_ROM_MATCH: // read ROM code bits
+ case ONEWIRE_STATE_FUNCTION_COMMAND: // read function command bits
+ case ONEWIRE_STATE_ROM_SEARCH_SELECT: // read selected ROM code bit
+ case ONEWIRE_STATE_FUNCTION_READ: // read function data bit
+ timer_enable_irq(TIM(ONEWIRE_SLAVE_TIMER), TIM_DIER_CC2IE); // enable timer for reading bit
+ break;
+ case ONEWIRE_STATE_ROM_READ: // send ROM code bit
+ case ONEWIRE_STATE_ROM_SEARCH_TRUE: // send ROM code bit while searching ROM, not negated
+ case ONEWIRE_STATE_ROM_SEARCH_FALSE: // send ROM code bit while searching ROM, already negated
+ case ONEWIRE_STATE_FUNCTION_WRITE: // write function data bit
+ timer_enable_irq(TIM(ONEWIRE_SLAVE_TIMER), TIM_DIER_CC2IE); // enable timer for reading bit
+ if (0==(bits_buffer&(1<<(bits_bit%8)))) { // need to send a 0 bit
+ gpio_clear(GPIO(ONEWIRE_SLAVE_PORT), GPIO(ONEWIRE_SLAVE_PIN)); // hold low to send 0 bit
+ }
+ break;
+ case ONEWIRE_STATE_IDLE: // we only expect a reset
+ default: // we don't expect any falling edge in other states
+ onewire_slave_state = ONEWIRE_STATE_IDLE; // unexpected signal, reset to idle state
+ break; // the timer overflow will confirm detect reset pulses
+ }
+ timer_clear_flag(TIM(ONEWIRE_SLAVE_TIMER), TIM_SR_UIF | TIM_SR_CC1IF | TIM_SR_CC2IF | TIM_SR_CC3IF | TIM_SR_CC4IF); // clear all flags
+ timer_enable_counter(TIM(ONEWIRE_SLAVE_TIMER)); // start timer to measure the configured timeouts
+ }
+}
+
+/** interrupt service routine called for timer */
+void TIM_ISR(ONEWIRE_SLAVE_TIMER)(void)
+{
+ if (timer_interrupt_source(TIM(ONEWIRE_SLAVE_TIMER), TIM_SR_UIF)) { // reset timer triggered, verify if it's a reset
+gpio_toggle(GPIO(TIMDBG_PORT), GPIO(TIMDBG_PIN1) | GPIO(TIMDBG_PIN2) | GPIO(TIMDBG_PIN3) | GPIO(TIMDBG_PIN4));
+ if (0==gpio_get(GPIO(ONEWIRE_SLAVE_PORT), GPIO(ONEWIRE_SLAVE_PIN))) { // signal it still low, thus it must be a reset
+ onewire_slave_state = ONEWIRE_STATE_RESET; // update state
+ }
+ timer_disable_counter(TIM(ONEWIRE_SLAVE_TIMER)); // stop timer since there is nothing more to measure
+ timer_disable_irq(TIM(ONEWIRE_SLAVE_TIMER), TIM_DIER_CC1IE | TIM_DIER_CC2IE | TIM_DIER_CC3IE | TIM_DIER_CC4IE); // disable all timers
+ timer_clear_flag(TIM(ONEWIRE_SLAVE_TIMER), TIM_SR_UIF | TIM_SR_CC1IF | TIM_SR_CC2IF | TIM_SR_CC3IF | TIM_SR_CC4IF); // clear all flag (I have no idea why the others are get too, even when the interrupt is not enabled)
+ }
+ if (timer_interrupt_source(TIM(ONEWIRE_SLAVE_TIMER), TIM_SR_CC1IF)) { // wait for presence pulse timer triggered
+gpio_toggle(GPIO(TIMDBG_PORT), GPIO(TIMDBG_PIN1));
+ timer_clear_flag(TIM(ONEWIRE_SLAVE_TIMER), TIM_SR_CC1IF); // clear flag
+ if (ONEWIRE_STATE_WAIT_PRESENCE==onewire_slave_state) { // we can now send the pulse
+ onewire_slave_state = ONEWIRE_STATE_PULSE_PRESENCE; // save new state
+ gpio_clear(GPIO(ONEWIRE_SLAVE_PORT), GPIO(ONEWIRE_SLAVE_PIN)); // send presence pulse (will also trigger the timer start)
+ }
+ }
+ if (timer_interrupt_source(TIM(ONEWIRE_SLAVE_TIMER), TIM_SR_CC2IF)) { // time to read the bit, or stop writing it
+ // read/write bit depending on bit
+gpio_toggle(GPIO(TIMDBG_PORT), GPIO(TIMDBG_PIN2));
+ switch (onewire_slave_state) {
+ case ONEWIRE_STATE_ROM_COMMAND: // read ROM command code bit
+ case ONEWIRE_STATE_ROM_MATCH: // read ROM code
+ case ONEWIRE_STATE_FUNCTION_COMMAND: // read function command code bit
+ case ONEWIRE_STATE_ROM_SEARCH_SELECT: // read selected ROM code bit
+ case ONEWIRE_STATE_FUNCTION_READ: // read function data bit
+ if (gpio_get(GPIO(ONEWIRE_SLAVE_PORT), GPIO(ONEWIRE_SLAVE_PIN))) { // bit is set to 1
+ bits_buffer |= (1<<(bits_bit%8)); // set bit
+ } else { // bit is set to 0
+ bits_buffer &= ~(1<<(bits_bit%8)); // clear bit
+ }
+ bits_bit++; // go to next bit
+ break;
+ case ONEWIRE_STATE_ROM_READ: // write ROM code
+ case ONEWIRE_STATE_FUNCTION_WRITE: // write function data bit
+ gpio_set(GPIO(ONEWIRE_SLAVE_PORT), GPIO(ONEWIRE_SLAVE_PIN)); // stop sending bit
+ bits_bit++; // go to next bit
+ break;
+ case ONEWIRE_STATE_ROM_SEARCH_TRUE: // ROM code bit is sent
+ case ONEWIRE_STATE_ROM_SEARCH_FALSE: // ROM code bit is sent
+ gpio_set(GPIO(ONEWIRE_SLAVE_PORT), GPIO(ONEWIRE_SLAVE_PIN)); // stop sending bit
+ break;
+ default: // these states don't need read/write
+ break;
+ }
+ static uint8_t rom_code_byte; // which byte of the ROM code is processed
+ // act on bit count
+ switch (onewire_slave_state) {
+ case ONEWIRE_STATE_ROM_COMMAND: // read ROM command
+ if (bits_bit>7) { // complete ROM command code received
+ bits_bit = 0; // reset buffer
+ rom_code_byte = 0; // reset ROM code byte index
+ switch (bits_buffer) { // act depending on ROM command code
+ case 0x33: // READ ROM
+ bits_buffer = onewire_slave_rom_code[rom_code_byte]; // prepare to send the first byte
+ onewire_slave_state = ONEWIRE_STATE_ROM_READ; // write ROM code
+ break;
+ case 0xcc: // SKIP ROM
+ onewire_slave_state = ONEWIRE_STATE_FUNCTION_COMMAND; // now read function command code
+ break;
+ case 0x55: // MATCH ROM
+ onewire_slave_state = ONEWIRE_STATE_ROM_MATCH; // read ROM code
+ break;
+ case 0xf0: // SEARCH ROM
+ bits_buffer = onewire_slave_rom_code[rom_code_byte]; // prepare to search code
+ onewire_slave_state = ONEWIRE_STATE_ROM_SEARCH_TRUE; // prepare to start sending first new bit
+ break;
+ default: // unknown ROM code
+ onewire_slave_state = ONEWIRE_STATE_IDLE; // go back to default idle state
+ break;
+ }
+ }
+ break;
+ case ONEWIRE_STATE_ROM_READ: // send ROM code
+ if (bits_bit>7) { // complete byte transmitted
+ rom_code_byte++; // go to next ROM code byte
+ if (rom_code_byte>LENGTH(onewire_slave_rom_code)) { // complete ROM code send
+ onewire_slave_state = ONEWIRE_STATE_IDLE; // go back to default idle state
+ } else {
+ bits_bit = 0; // reset buffer
+ bits_buffer = onewire_slave_rom_code[rom_code_byte]; // send next ROM code byte
+ }
+ }
+ break;
+ case ONEWIRE_STATE_ROM_MATCH: // compare ROM code
+ if (bits_bit>7) { // complete byte received
+ if (bits_buffer==onewire_slave_rom_code[rom_code_byte]) { // ROM code byte matches
+ bits_bit = 0; // reset buffer
+ rom_code_byte++; // go to next ROM code byte
+ if (rom_code_byte>=LENGTH(onewire_slave_rom_code)) { // complete ROM code matches
+ onewire_slave_state = ONEWIRE_STATE_FUNCTION_COMMAND; // now read function command code
+ }
+ } else { // ROM code does not match
+ onewire_slave_state = ONEWIRE_STATE_IDLE; // stop comparing and go back to idle
+ }
+ }
+ break;
+ case ONEWIRE_STATE_ROM_SEARCH_TRUE: // ROM code bit is send, prepare to send negated version
+ bits_buffer ^= (1<7) { // complete byte searched
+ bits_bit = 0; // reset buffer
+ rom_code_byte++; // go to next ROM code byte
+ if (rom_code_byte>=LENGTH(onewire_slave_rom_code)) { // complete ROM code search
+ onewire_slave_state = ONEWIRE_STATE_FUNCTION_COMMAND; // now read function command code
+ } else {
+ bits_buffer = onewire_slave_rom_code[rom_code_byte]; // prepare next ROM code byte
+ }
+ }
+ break;
+ case ONEWIRE_STATE_FUNCTION_COMMAND: // read function command
+ if (bits_bit>7) { // complete function command code received
+ onewire_slave_function_code = bits_buffer; // save function command code to user buffer
+ onewire_slave_state = ONEWIRE_STATE_FUNCTION_DATA; // let the user transfer data
+ onewire_slave_function_code_received = true; // notify user
+ }
+ break;
+ case ONEWIRE_STATE_FUNCTION_READ: // save function data bit
+ if (0==bits_bit%8) { // complete byte received
+ onewire_slave_transfer_data[(bits_bit-1)/8] = bits_buffer; // save received bytes
+ }
+ if (bits_bit>=onewire_slave_transfer_bits) { // read transfer complete
+ onewire_slave_transfer_data[(bits_bit-1)/8] = bits_buffer; // save last bits
+ onewire_slave_state = ONEWIRE_STATE_FUNCTION_DATA; // let the user transfer more data
+ onewire_slave_transfer_complete = true; // notify user
+ }
+ break;
+ case ONEWIRE_STATE_FUNCTION_WRITE: // update function data bit to write
+ if (0==bits_bit%8) { // complete byte transfer
+ bits_buffer = onewire_slave_transfer_data[bits_bit/8]; // prepare next byte to write
+ }
+ if (bits_bit>=onewire_slave_transfer_bits) { // write transfer complete
+ onewire_slave_state = ONEWIRE_STATE_FUNCTION_DATA; // let the user transfer more data
+ onewire_slave_transfer_complete = true; // notify user
+ }
+ break;
+ default: // no action needed
+ break;
+ }
+ timer_clear_flag(TIM(ONEWIRE_SLAVE_TIMER), TIM_SR_CC2IF); // clear flag
+ }
+ if (timer_interrupt_source(TIM(ONEWIRE_SLAVE_TIMER), TIM_SR_CC3IF)) { // end of presence pulse timer triggered
+gpio_toggle(GPIO(TIMDBG_PORT), GPIO(TIMDBG_PIN3));
+ timer_clear_flag(TIM(ONEWIRE_SLAVE_TIMER), TIM_SR_CC3IF); // clear flag
+ if (ONEWIRE_STATE_PULSE_PRESENCE==onewire_slave_state) {
+ gpio_set(GPIO(ONEWIRE_SLAVE_PORT), GPIO(ONEWIRE_SLAVE_PIN)); // stop sending presence pulse
+ // if the pin stays low the reset timer will catch it
+ }
+ }
+ if (timer_get_flag(TIM(ONEWIRE_SLAVE_TIMER), TIM_SR_CC4IF)) { // end of slot timer triggered (not used)
+gpio_toggle(GPIO(TIMDBG_PORT), GPIO(TIMDBG_PIN4));
+ timer_clear_flag(TIM(ONEWIRE_SLAVE_TIMER), TIM_SR_CC4IF); // clear flag
+ }
+}
diff --git a/lib/onewire_slave.h b/lib/onewire_slave.h
new file mode 100644
index 0000000..0fe9d32
--- /dev/null
+++ b/lib/onewire_slave.h
@@ -0,0 +1,51 @@
+/* This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see .
+ *
+ */
+/** library for 1-wire protocol as slave (API)
+ * @file onewire_slave.h
+ * @author King Kévin
+ * @date 2017
+ * @note peripherals used: timer @ref onewire_slave_timer, GPIO @ref onewire_slave_gpio
+ * @note overdrive mode is not supported
+ */
+#pragma once
+
+/** set when a function command code has been received
+ * @note needs to be cleared by user
+ */
+extern volatile bool onewire_slave_function_code_received;
+/** last function command code received */
+extern volatile uint8_t onewire_slave_function_code;
+/** set when data read/write transfer has been completed
+ * @note needs to be cleared by user
+ */
+extern volatile bool onewire_slave_transfer_complete;
+
+/** setup 1-wire peripheral
+ * @param[in] family family code for slave ROM code (8 bits)
+ * @param[in] serial serial number for slave ROM code (48 bits)
+ */
+void onewire_slave_setup(uint8_t family, uint64_t serial);
+/** read data from master
+ * @param[out] data buffer to save read bits
+ * @param[in] bits number of bits to read
+ * @note onewire_slave_transfer_complete is set when transfer is completed
+ */
+void onewire_slave_function_read(uint8_t* data, uint32_t bits);
+/** write data to master
+ * @param[in] data data to write
+ * @param[in] bits number of bits to write
+ * @note onewire_slave_transfer_complete is set when transfer is completed
+ */
+void onewire_slave_function_write(uint8_t* data, uint32_t bits);