measurement_fw/owi.c

#include "owi.h"
#include "r_cg_wdt.h"
#include "delay.h"
#include <string.h>

/* 내부 상태 */
static uint32_t bit_period_us = OWI_BIT_PERIOD_US;
static uint8_t  g_owi_timeout_latched = 0;

static uint16_t g_owi_last_timeout_byte_index = 0xFFFFu;
static uint8_t  g_owi_last_timeout_bit_index  = 0xFFu;

static uint16_t g_owi_current_read_byte_index = 0u;
static uint8_t  g_owi_current_read_bit_index  = 0u;

static void OWI_KickWdt(void)
{
    R_WDT_Restart();
}

/* =========================================================
 * GPIO helpers (P70 / HW Open-Drain)
 * - LOW  : 출력 모드 + 0
 * - HIGH : 입력(Hi-Z)로 release
 * ========================================================= */
void GPIO_Clear(void)
{
    OWI_PORT_POM |= (uint8_t)OWI_PIN_MASK;
    OWI_PORT_P   &= (uint8_t)~OWI_PIN_MASK;
    OWI_PORT_PM  &= (uint8_t)~OWI_PIN_MASK;
}

void GPIO_Input(void)
{
    OWI_PORT_POM |= (uint8_t)OWI_PIN_MASK;
    OWI_PORT_P   |= (uint8_t)OWI_PIN_MASK;
    OWI_PORT_PM  |= (uint8_t)OWI_PIN_MASK;
}

int GPIO_Read(void)
{
    return (OWI_PORT_P & (uint8_t)OWI_PIN_MASK) ? 1 : 0;
}

static void OWI_Release(void)
{
    OWI_PORT_POM |= (uint8_t)OWI_PIN_MASK;
    OWI_PORT_P   |= (uint8_t)OWI_PIN_MASK;
    OWI_PORT_PM  |= (uint8_t)OWI_PIN_MASK;
}

static void OWI_DriveLow(void)
{
    OWI_PORT_POM |= (uint8_t)OWI_PIN_MASK;
    OWI_PORT_P   &= (uint8_t)~OWI_PIN_MASK;
    OWI_PORT_PM  &= (uint8_t)~OWI_PIN_MASK;
}

/* =========================================================
 * Diagnostics
 * ========================================================= */
uint8_t OWI_HasTimeout(void)
{
    return g_owi_timeout_latched;
}

void OWI_ClearTimeout(void)
{
    g_owi_timeout_latched = 0;
    g_owi_last_timeout_byte_index = 0xFFFFu;
    g_owi_last_timeout_bit_index  = 0xFFu;
}

uint16_t OWI_GetLastTimeoutByteIndex(void)
{
    return g_owi_last_timeout_byte_index;
}

uint8_t OWI_GetLastTimeoutBitIndex(void)
{
    return g_owi_last_timeout_bit_index;
}

/* =========================================================
 * OWI Init
 * ========================================================= */
void OWI_Init(uint32_t bit_time_us)
{
    bit_period_us = bit_time_us;
    (void)bit_period_us;

    OWI_PORT_POM |= (uint8_t)OWI_PIN_MASK;
    OWI_PORT_PU &= (uint8_t)~OWI_PIN_MASK;

    OWI_ClearTimeout();
    GPIO_Input();
    OWI_KickWdt();
}

/* =========================================================
 * Start/Stop/Secure
 * ========================================================= */
void OWI_Start(void)
{
    GPIO_Clear();
    delay_us(TSTART_HOLD);

    GPIO_Input();
    delay_us(TBIT);
}

void OWI_Stop(void)
{
    GPIO_Input();
    delay_us(TSTOP_LOW);
    delay_us(TIDLE);
}

static void OWI_StopRead(void)
{
    OWI_DriveLow();
    delay_us(TSTOP_LOW);
    OWI_Release();
    delay_us(TIDLE);
}

static uint8_t OWI_WaitForFallingEdge(uint16_t byte_index, uint8_t bit_index)
{
    int timeout = (int)(bit_period_us * 4u);

    while (GPIO_Read() && timeout-- > 0) {
        delay_us(1u);
    }

    if (timeout <= 0) {
        if (!g_owi_timeout_latched) {
            g_owi_timeout_latched = 1;
            g_owi_last_timeout_byte_index = byte_index;
            g_owi_last_timeout_bit_index  = bit_index;
        }
        return 0u;
    }

    return 1u;
}

static uint8_t OWI_ReadByte_StreamSynced(uint16_t byte_index)
{
    uint8_t data = 0;
    int b;

    for (b = 7; b >= 0; b--) {
        uint8_t bit_index = (uint8_t)(7 - b);
        uint8_t bit;

        g_owi_current_read_byte_index = byte_index;
        g_owi_current_read_bit_index  = bit_index;

        /* 슬롯 시작 후 중앙 샘플 */
        delay_us(bit_period_us / 2u);
        bit = GPIO_Read() ? 1u : 0u;
        data |= (uint8_t)(bit << b);

        /* 남은 반 슬롯 대기 */
        delay_us(bit_period_us / 2u);
    }

    return data;
}

void OWI_SecureStop(void)
{
    int i;

    GPIO_Clear();
    delay_us(SECURE_HIGH);

    for (i = 0; i < (int)SECURE_TOGGLE_COUNT; i++) {
        GPIO_Input();
        delay_us(SECURE_TOGGLE_HIGH);

        GPIO_Clear();
        delay_us(SECURE_TOGGLE_LOW);
    }

    GPIO_Input();
    delay_us(SECURE_HIGH);

    GPIO_Clear();
    delay_us(TSTART_HOLD);
    GPIO_Input();
}

/* =========================================================
 * Bit/Byte IO
 * ========================================================= */
void OWI_WriteBit(int bit)
{
    uint32_t t_low  = bit ? (uint32_t)TLOW_1 : (uint32_t)TLOW_0;
    uint32_t t_high = (uint32_t)TBIT - t_low;

    /* HIGH 구간 */
    OWI_Release();
    delay_us(t_high);

    /* LOW 구간 */
    OWI_DriveLow();
    delay_us(t_low);

    /* 다음 슬롯 시작 전 반드시 release */
    OWI_Release();
}

void OWI_WriteByte(uint8_t data)
{
    int i;
    for (i = 7; i >= 0; i--) {
        OWI_WriteBit((data >> i) & 0x01u);
    }
    GPIO_Input();
}

uint8_t OWI_ReadBit(void)
{
    int timeout;
    int low_width = 0;

    /* 1) 라인이 HIGH가 될 때까지 정리 */
    timeout = (int)(bit_period_us * 2u);
    while (!GPIO_Read() && timeout-- > 0) {
        delay_us(1u);
    }

    if (timeout <= 0) {
        if (!g_owi_timeout_latched) {
            g_owi_timeout_latched = 1;
            g_owi_last_timeout_byte_index = g_owi_current_read_byte_index;
            g_owi_last_timeout_bit_index  = g_owi_current_read_bit_index;
        }
        return 0u;
    }

    /* 2) 다음 LOW 시작 대기 */
    timeout = (int)(bit_period_us * 2u);
    while (GPIO_Read() && timeout-- > 0) {
        delay_us(1u);
    }

    if (timeout <= 0) {
        if (!g_owi_timeout_latched) {
            g_owi_timeout_latched = 1;
            g_owi_last_timeout_byte_index = g_owi_current_read_byte_index;
            g_owi_last_timeout_bit_index  = g_owi_current_read_bit_index;
        }
        return 0u;
    }

    /* 3) LOW가 유지되는 시간을 직접 측정 */
    while (!GPIO_Read() && low_width < (int)(bit_period_us * 2u)) {
        delay_us(1u);
        low_width++;
    }

    /* 4) LOW 폭 기준으로 판정
       - 짧으면 1
       - 길면 0
       threshold ~= TBIT/2
    */
    return (low_width < (int)(bit_period_us / 2u)) ? 1u : 0u;
}

uint8_t OWI_ReadByte(void)
{
    uint8_t data = 0;
    int i;

    for (i = 7; i >= 0; i--) {
        g_owi_current_read_bit_index = (uint8_t)(7 - i);
        data |= (uint8_t)(OWI_ReadBit() << i);
        if (OWI_HasTimeout()) {
            break;
        }
    }
    return data;
}

/* =========================================================
 * Raw helpers
 * ========================================================= */
static void owi_result_init(owi_io_result_t *r)
{
    if (!r) return;
    memset(r, 0, sizeof(*r));
    r->ok = 1;
    r->timeout_byte_index = 0xFFFFu;
    r->timeout_bit_index  = 0xFFu;
}

static void owi_result_latch_timeout(owi_io_result_t *r)
{
    if (!r) return;

    if (OWI_HasTimeout()) {
        r->ok = 0;
        r->timeout = 1;
        r->timeout_byte_index = OWI_GetLastTimeoutByteIndex();
        r->timeout_bit_index  = OWI_GetLastTimeoutBitIndex();
    }
}

void OWI_T_CommandModeRaw(const uint8_t *tx_data, uint8_t tx_len, uint8_t id, owi_io_result_t *r)
{
    int i;

    owi_result_init(r);

    //delay_us(200);
    OWI_Init(OWI_BIT_PERIOD_US);
    OWI_ClearTimeout();

    OWI_KickWdt();
    OWI_SecureStop();
    OWI_KickWdt();
    OWI_WriteByte((uint8_t)(id << 1));
    OWI_KickWdt();

    for (i = 0; i < (int)tx_len; i++) {
        OWI_KickWdt();
        OWI_WriteByte(tx_data[i]);
        OWI_KickWdt();
    }

    OWI_Stop();
    OWI_KickWdt();
    owi_result_latch_timeout(r);
}

void OWI_CommandModeRaw(const uint8_t *tx_data, uint8_t tx_len, uint8_t id, owi_io_result_t *r)
{
    int i;

    owi_result_init(r);
    OWI_Init(OWI_BIT_PERIOD_US);
    OWI_ClearTimeout();

    OWI_KickWdt();
    OWI_SecureStop();
    OWI_KickWdt();
    OWI_WriteByte((uint8_t)(id << 1));
    OWI_KickWdt();

    for (i = 0; i < (int)tx_len; i++) {
        OWI_KickWdt();
        OWI_WriteByte(tx_data[i]);
        OWI_KickWdt();
    }

    OWI_Stop();
    OWI_KickWdt();
    owi_result_latch_timeout(r);
}

void OWI_ReadBytesRaw(int length, uint8_t id, owi_io_result_t *r)
{
    int i;
    int max_len;
    uint8_t is_long_read;

    if (!r) return;

    owi_result_init(r);
    OWI_Init(OWI_BIT_PERIOD_US);

    if (length <= 0) {
        r->ok = 0;
        return;
    }

    max_len = (int)OWI_IO_MAX_BYTES;
    if (length > max_len) {
        length = max_len;
    }

    r->read_len = (uint16_t)length;
    OWI_ClearTimeout();

    is_long_read = (length >= 119) ? 1u : 0u;

    OWI_KickWdt();
    OWI_SecureStop();
    OWI_WriteByte((uint8_t)((id << 1) | 1u));

    /* 기존 잘 되던 값 유지 */
    delay_us(100u);
    OWI_KickWdt();

    /* 첫 falling edge를 한 번 잡는다 */
    if (!OWI_WaitForFallingEdge(0u, 0u)) {
        owi_result_latch_timeout(r);
        OWI_StopRead();
        OWI_KickWdt();
        return;
    }

    for (i = 0; i < length; i++) {
        OWI_KickWdt();

        /* long read만 주기적 재동기화 */
        if (is_long_read && i == (length - 50)) {
            OWI_KickWdt();
	    if (!OWI_WaitForFallingEdge((uint16_t)i, 0u)) {
	        owi_result_latch_timeout(r);
	        break;
	    }
	}

        r->data[i] = OWI_ReadByte_StreamSynced((uint16_t)i);

        if (OWI_HasTimeout()) {
            owi_result_latch_timeout(r);
            break;
        }
    }

    OWI_StopRead();
    OWI_KickWdt();
}