diff --git a/lib/microwire_master.c b/lib/microwire_master.c
new file mode 100644
index 0000000..bff991d
--- /dev/null
+++ b/lib/microwire_master.c
@@ -0,0 +1,315 @@
+/* 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 to communicate using microwore as master (code)
+ * @file microwire_master.c
+ * @author King Kévin
+ * @date 2017
+ * @note peripherals used: GPIO @ref microwire_master_gpio, timer @ref microwire_master_timer
+ * microwire is a 3-Wire half-duplex synchronous bus. It is very similar to SPI without fixed length messages (bit-wised).
+ * @note the user has to handle the slave select pin (high during operations) so to be able to handle multiple slaves.
+ * @warning this library implements the M93Cx8 EEPROM operation codes. Other microwire-based ICs might use different ones.
+ */
+
+/* standard libraries */
+#include // standard integer types
+#include // general utilities
+
+/* STM32 (including CM3) libraries */
+#include // Cortex M3 utilities
+#include // real-time control clock library
+#include // general purpose input output library
+#include // timer utilities
+
+#include "global.h" // global utilities
+#include "microwire_master.h" // microwire header and definitions
+
+/** @defgroup microwire_master_gpio GPIO peripheral used to communicate
+ * @{
+ */
+#define MICROWIRE_MASTER_SDO_PORT A /**< SDO output signal port (to be connected on D slave signal) */
+#define MICROWIRE_MASTER_SDO_PIN 0 /**< SDO output signal pin (to be connected on D slave signal) */
+#define MICROWIRE_MASTER_SDI_PORT A /**< SDO input signal port (to be connected on Q slave signal) */
+#define MICROWIRE_MASTER_SDI_PIN 2 /**< SDO input signal pin (to be connected on Q slave signal) */
+#define MICROWIRE_MASTER_SCK_PORT A /**< SCK output signal port (to be connected on C slave signal) */
+#define MICROWIRE_MASTER_SCK_PIN 4 /**< SCK output signal pin (to be connected on C slave signal) */
+/** @} */
+
+/** @defgroup microwire_master_timer timer peripheral used to generate timing for the signal
+ * @{
+ */
+#define MICROWIRE_MASTER_TIMER 4 /**< timer peripheral */
+/** @} */
+
+/** address size used in operations (slave specific) */
+uint8_t mirowire_master_address_size = 0;
+/** organization used (true=x16, false=x8) */
+bool mirowire_master_organization_x16 = true;
+
+void microwire_master_setup(uint32_t frequency, bool organization_x16, uint8_t address_size)
+{
+ // sanity checks
+ if (0==frequency || 0==address_size) {
+ return;
+ }
+ mirowire_master_address_size = address_size; // save address size
+ mirowire_master_organization_x16 = organization_x16; // save organisation
+
+ // setup GPIO
+ rcc_periph_clock_enable(RCC_GPIO(MICROWIRE_MASTER_SDO_PORT)); // enable clock for GPIO domain for SDO signal
+ gpio_set_mode(GPIO(MICROWIRE_MASTER_SDO_PORT), GPIO_MODE_OUTPUT_10_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO(MICROWIRE_MASTER_SDO_PIN)); // set SDO signal as output (controlled by the master)
+ gpio_clear(GPIO(MICROWIRE_MASTER_SDO_PORT), GPIO(MICROWIRE_MASTER_SDO_PIN)); // SDO is idle low
+ rcc_periph_clock_enable(RCC_GPIO(MICROWIRE_MASTER_SDI_PORT)); // enable clock for GPIO domain for SDI signal
+ gpio_set_mode(GPIO(MICROWIRE_MASTER_SDI_PORT), GPIO_MODE_INPUT, GPIO_CNF_INPUT_FLOAT, GPIO(MICROWIRE_MASTER_SDI_PIN)); // set SDI signal as output (controlled by the slave)
+ rcc_periph_clock_enable(RCC_GPIO(MICROWIRE_MASTER_SCK_PORT)); // enable clock for GPIO domain for SCK signal
+ gpio_set_mode(GPIO(MICROWIRE_MASTER_SCK_PORT), GPIO_MODE_OUTPUT_10_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, GPIO(MICROWIRE_MASTER_SCK_PIN)); // set SCK signal as output (controlled by the master)
+ gpio_clear(GPIO(MICROWIRE_MASTER_SCK_PORT), GPIO(MICROWIRE_MASTER_SCK_PIN)); // SCK is idle low
+
+ // setup timer to generate timing for the signal
+ rcc_periph_clock_enable(RCC_TIM(MICROWIRE_MASTER_TIMER)); // enable clock for timer domain
+ timer_reset(TIM(MICROWIRE_MASTER_TIMER)); // reset timer state
+ timer_set_mode(TIM(MICROWIRE_MASTER_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
+ uint16_t prescaler = rcc_ahb_frequency/(frequency*2)/(uint32_t)(1<<16)+1; // calculate prescaler for most accurate timing for this speed
+ timer_set_prescaler(TIM(MICROWIRE_MASTER_TIMER), prescaler-1); // set calculated prescaler
+ uint16_t period = (rcc_ahb_frequency/prescaler)/(frequency*2); // calculate period to get most accurate timing based on the calculated prescaler
+ timer_set_period(TIM(MICROWIRE_MASTER_TIMER), period-1); // set calculated period
+ timer_update_on_overflow(TIM(MICROWIRE_MASTER_TIMER)); // only use counter overflow as UEV source (use overflow as timeout)
+ SCB_SCR |= SCB_SCR_SEVEONPEND; // enable wake up on event (instead of using ISR)
+ timer_enable_irq(TIM(MICROWIRE_MASTER_TIMER), TIM_DIER_UIE); // enable update interrupt for timer
+}
+
+/** wait for clock tick used to synchronise communication */
+static void microwire_master_wait_clock(void)
+{
+ while ( !timer_get_flag(TIM(MICROWIRE_MASTER_TIMER), TIM_SR_UIF)) { // wait for timer overflow event for clock change
+ __asm__("wfe"); // go to sleep and wait for event
+ }
+ timer_clear_flag(TIM(MICROWIRE_MASTER_TIMER), TIM_SR_UIF); // clear timer flag
+ nvic_clear_pending_irq(NVIC_TIM_IRQ(MICROWIRE_MASTER_TIMER)); // clear IRQ flag (else event doesn't wake up)
+
+}
+
+/** send bit over microwire
+ * @param[in] bit bit to send (true = '1', false = '0')
+ */
+static void microwire_master_send_bit(bool bit)
+{
+ if (bit) {
+ gpio_set(GPIO(MICROWIRE_MASTER_SDO_PORT), GPIO(MICROWIRE_MASTER_SDO_PIN)); // set '1' on output
+ } else {
+ gpio_clear(GPIO(MICROWIRE_MASTER_SDO_PORT), GPIO(MICROWIRE_MASTER_SDO_PIN)); // set '0' on output
+ }
+ microwire_master_wait_clock(); // wait for clock timing
+ gpio_set(GPIO(MICROWIRE_MASTER_SCK_PORT), GPIO(MICROWIRE_MASTER_SCK_PIN)); // make rising edge for slave to sample
+ microwire_master_wait_clock(); // keep output signal stable while clock is high
+ gpio_clear(GPIO(MICROWIRE_MASTER_SCK_PORT), GPIO(MICROWIRE_MASTER_SCK_PIN)); // put clock back to idle
+}
+
+/** initialize microwire communication and send header (with leading start bit '1')
+ * @param[in] operation operation code to send (2 bits)
+ * @param[in] address slave memory address to select
+ */
+static void microwire_master_start(uint8_t operation, uint32_t address)
+{
+ // to sanity checks
+ if (0==mirowire_master_address_size) { // can't send address
+ return;
+ }
+
+ // initial setup
+ gpio_clear(GPIO(MICROWIRE_MASTER_SCK_PORT), GPIO(MICROWIRE_MASTER_SCK_PIN)); // ensure clock is low (to sample on rising edge)
+ timer_set_counter(TIM(MICROWIRE_MASTER_TIMER),0); // reset timer counter
+ timer_clear_flag(TIM(MICROWIRE_MASTER_TIMER), TIM_SR_UIF); // clear timer flag
+ nvic_clear_pending_irq(NVIC_TIM_IRQ(MICROWIRE_MASTER_TIMER)); // clear IRQ flag (else event doesn't wake up)
+ timer_enable_counter(TIM(MICROWIRE_MASTER_TIMER)); // start timer to generate timing
+
+ // send '1' start bit
+ microwire_master_send_bit(true); // send start bit
+ // send two bits operation code
+ if (operation&0x2) { // send first bit (MSb first)
+ microwire_master_send_bit(true); // send '1'
+ } else {
+ microwire_master_send_bit(false); // send '2'
+ }
+ if (operation&0x1) { // send second bit (LSb last)
+ microwire_master_send_bit(true); // send '1'
+ } else {
+ microwire_master_send_bit(false); // send '2'
+ }
+
+ // send address
+ for (uint8_t bit = mirowire_master_address_size; bit > 0; bit--) {
+ if ((address>>(bit-1))&0x01) {
+ microwire_master_send_bit(true); // send '1' address bit
+ } else {
+ microwire_master_send_bit(false); // send '0' address bit
+ }
+ }
+ gpio_clear(GPIO(MICROWIRE_MASTER_SDO_PORT), GPIO(MICROWIRE_MASTER_SDO_PIN)); // ensure output is idle low (could be floating)
+}
+
+/** stop microwire communication and end all activities */
+static void microwire_master_stop(void)
+{
+ timer_disable_counter(TIM(MICROWIRE_MASTER_TIMER)); // disable timer
+ timer_set_counter(TIM(MICROWIRE_MASTER_TIMER),0); // reset timer counter
+ timer_clear_flag(TIM(MICROWIRE_MASTER_TIMER), TIM_SR_UIF); // clear timer flag
+ nvic_clear_pending_irq(NVIC_TIM_IRQ(MICROWIRE_MASTER_TIMER)); // clear IRQ flag
+ gpio_clear(GPIO(MICROWIRE_MASTER_SCK_PORT), GPIO(MICROWIRE_MASTER_SCK_PIN)); // ensure clock is idle low
+ gpio_clear(GPIO(MICROWIRE_MASTER_SDO_PORT), GPIO(MICROWIRE_MASTER_SDO_PIN)); // ensure output is idle low
+}
+
+
+/** read bit from microwire communication
+ * @return bit value (true = '1', false = '0')
+ */
+static bool microwire_master_read_bit(void)
+{
+ microwire_master_wait_clock(); // wait for clock timing
+ gpio_set(GPIO(MICROWIRE_MASTER_SCK_PORT), GPIO(MICROWIRE_MASTER_SCK_PIN)); // make rising edge for slave to output data
+ microwire_master_wait_clock(); // wait for signal to be stable
+ gpio_clear(GPIO(MICROWIRE_MASTER_SCK_PORT), GPIO(MICROWIRE_MASTER_SCK_PIN)); // set clock low again
+ return 0!=gpio_get(GPIO(MICROWIRE_MASTER_SDI_PORT), GPIO(MICROWIRE_MASTER_SDI_PIN)); // read input signal
+}
+
+void microwire_master_read(uint32_t address, uint16_t* data, size_t length)
+{
+ // to sanity checks
+ if (NULL==data || 0==length || 0==mirowire_master_address_size) { // can't save data
+ return;
+ }
+
+ microwire_master_start(0x02, address); // send '10' READ instruction and memory address
+
+ // there should already be a '0' dummy bit
+ if (0!=gpio_get(GPIO(MICROWIRE_MASTER_SDI_PORT), GPIO(MICROWIRE_MASTER_SDI_PIN))) { // the dummy bit wasn't '0'
+ goto clean;
+ }
+
+ // read data
+ for (size_t i=0; i0; b--) {
+ if (microwire_master_read_bit()) { // read bit, MSb first
+ data[i] |= (1<<(b-1)); // set bit
+ } else {
+ data[i] &= ~(1<<(b-1)); // clear bit
+ }
+ }
+ }
+
+clean:
+ microwire_master_stop(); // stop communication and clean up
+}
+
+void microwire_master_write_enable(void)
+{
+ // to sanity checks
+ if (mirowire_master_address_size<2) { // can't send '11...' address
+ return;
+ }
+
+ microwire_master_start(0x0, 0x3<<(mirowire_master_address_size-2)); // send '00' WEN operation code and '11...' address
+ microwire_master_stop(); // clean up
+}
+
+void microwire_master_write_disable(void)
+{
+ // to sanity checks
+ if (mirowire_master_address_size<2) { // can't send '00...' address
+ return;
+ }
+
+ microwire_master_start(0x0, 0); // send '00' WDS operation code and '00...' address
+ microwire_master_stop(); // clean up
+}
+
+void microwire_master_write(uint32_t address, uint16_t data)
+{
+ // to sanity checks
+ if (0==mirowire_master_address_size) { // can't send address
+ return;
+ }
+
+ microwire_master_start(0x01, address); // send '01' WRITE operation code and memory address
+
+ // write data (MSb first)
+ for (uint8_t b=(mirowire_master_organization_x16 ? 16 : 8); b>0; b--) {
+ if (data&(1<<(b-1))) { // bit is set
+ microwire_master_send_bit(true); // send '1' data bit
+ } else {
+ microwire_master_send_bit(false); // send '0' data bit
+ }
+ }
+
+ microwire_master_stop(); // clean up
+}
+
+void microwire_master_wait_ready(void)
+{
+
+ // initial setup
+ gpio_clear(GPIO(MICROWIRE_MASTER_SCK_PORT), GPIO(MICROWIRE_MASTER_SCK_PIN)); // ensure clock is low (to sample on rising edge)
+ timer_set_counter(TIM(MICROWIRE_MASTER_TIMER),0); // reset timer counter
+ timer_clear_flag(TIM(MICROWIRE_MASTER_TIMER), TIM_SR_UIF); // clear timer flag
+ nvic_clear_pending_irq(NVIC_TIM_IRQ(MICROWIRE_MASTER_TIMER)); // clear IRQ flag (else event doesn't wake up)
+ timer_enable_counter(TIM(MICROWIRE_MASTER_TIMER)); // start timer to generate timing
+
+
+ // SDI low on busy, high on ready, clock is ignored
+ while (!microwire_master_read_bit()); // wait until slave is ready
+
+ microwire_master_stop(); // clean up
+}
+
+void microwire_master_erase(uint32_t address)
+{
+ // sanity checks
+ if (0==mirowire_master_address_size) { // can't send address
+ return;
+ }
+
+ microwire_master_start(0x03, address); // send '11' ERASE operation code and memory address
+ microwire_master_stop(); // clean up
+}
+
+void microwire_master_erase_all(void)
+{
+ // sanity checks
+ if (mirowire_master_address_size<2) { // can't send '11...' address
+ return;
+ }
+
+ microwire_master_start(0x00, 0x2<<(mirowire_master_address_size-2)); // send '00' ERAL operation code and '10...' address
+ microwire_master_stop(); // clean up
+}
+
+void microwire_master_write_all(uint16_t data)
+{
+ // sanity checks
+ if (0==mirowire_master_address_size) { // can't send address
+ return;
+ }
+
+ microwire_master_start(0x00, 0x1<<(mirowire_master_address_size-2)); // send '00' WRAL operation code and '01...' address
+ // write data (MSb first)
+ for (uint8_t b=(mirowire_master_organization_x16 ? 16 : 8); b>0; b--) {
+ if (data&(1<<(b-1))) { // bit is set
+ microwire_master_send_bit(true); // send '1' data bit
+ } else {
+ microwire_master_send_bit(false); // send '0' data bit
+ }
+ }
+
+ microwire_master_stop(); // clean up
+}
diff --git a/lib/microwire_master.h b/lib/microwire_master.h
new file mode 100644
index 0000000..6a6e47d
--- /dev/null
+++ b/lib/microwire_master.h
@@ -0,0 +1,68 @@
+/* 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 to communicate using microwore as master (API)
+ * @file microwire_master.h
+ * @author King Kévin
+ * @date 2017
+ * @note peripherals used: GPIO @ref microwire_master_gpio, timer @ref microwire_master_timer
+ * microwire is a 3-Wire half-duplex synchronous bus. It is very similar to SPI without fixed length messages (bit-wised).
+ * @note the user has to handle the slave select pin (high during operations) so to be able to handle multiple slaves.
+ * @warning this library implements the M93Cx8 EEPROM operation codes. Other microwire-based ICs might use different ones.
+ */
+#pragma once
+
+/** setup microwire peripheral
+ * @param[in] frequency clock frequency in Hz
+ * @param[in] organization_x16 if x16 memory organization (16-bits) is used, or x8 (8-bits)
+ * @param[in] address_size address size in bits
+ * @note frequency practically limited to 500 kHz due to the software implementation nature
+ */
+void microwire_master_setup(uint32_t frequency, bool organization_x16, uint8_t address_size);
+/** read data from slave memory
+ * @param[in] address memory address of data to read
+ * @param[out] data array to store read data
+ * @param[in] length number of data bytes/words to read
+ */
+void microwire_master_read(uint32_t address, uint16_t* data, size_t length);
+/** enable write and erase operations
+ * @note on slave boot write is disable to prevent corruption
+ */
+void microwire_master_write_enable(void);
+/** disable write and erase operations
+ * @note this should be done after every complete write operation to protect against corruption
+ */
+void microwire_master_write_disable(void);
+/** write data to slave memory
+ * @param[in] address memory address of data to read
+ * @param[in] data byte/word to write
+ * @note after each write and before the next operation user should wait for the slave to be ready
+ */
+void microwire_master_write(uint32_t address, uint16_t data);
+/** wait until slave is ready after a write or erase */
+void microwire_master_wait_ready(void);
+/** erase memory
+ * @param[in] address memory address of data to read
+ * @note after each erase and before the next operation user should wait for the slave to be ready
+ */
+void microwire_master_erase(uint32_t address);
+/** erase all memory
+ * @note after each erase and before the next operation user should wait for the slave to be ready
+ */
+void microwire_master_erase_all(void);
+/** write data to all slave memory
+ * @param[in] data byte/word to write
+ * @note after each write and before the next operation user should wait for the slave to be ready
+ */
+void microwire_master_write_all(uint16_t data);