1wire-search/main.c

#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
#include <stdbool.h>
#include <inttypes.h>

#include "ow_search.h"

// ----------- DEMO -----------------

int main(void)
{
    // The search algorithm stores its internal state in a struct.

    // This allows calling it repeatedly if there are more devices
    // than could fit in the address buffer.

    struct ow_search_state search_state;
    ow_search_init(&search_state, 0xF0 /* SEARCH_ROM */, false /* checksums */);

    // Buffer for the found addresses - can have up to 65536 rows
    // Keep in mind that each address uses 8 bytes
    #define CODE_BUFFER_LEN 8
    ow_romcode_t addresses[CODE_BUFFER_LEN];

    // The algorithm stores its return value in the status field,
    // we can loop until it becomes OW_SEARCH_DONE or OW_SEARCH_FAILED
    while (search_state.status == OW_SEARCH_MORE) {
        // Perform a run of the algorithm
        uint16_t count = ow_search_run(&search_state, addresses, CODE_BUFFER_LEN);

        // Do something with the found addresses
        printf("Found %d addresses, status %d\n", count, search_state.status);
        for (int i = 0; i < count; i++) {
            printf("> ");
            for (int j = 0; j < 8; j++) {
                printf("%02x ", addresses[i][j]);
            }
            uint64_t numeric = ow_romcode_to_u64(addresses[i]);
            printf(" (0x%016"PRIx64")\n", numeric);
        }
        printf("\n");
    }

    return 0;
}

// ------------ SIMULATOR ---------------

// A simple 1-wire bus simulation following the real behavior of bus devices
// in the search operation.

struct owunit {
    ow_romcode_t romcode;
    bool selected;
    uint8_t rompos;
    int state;
};

#define UNITS_COUNT 13
struct owunit units[UNITS_COUNT] = {
    {.romcode = {0b00000000}},//00
    {.romcode = {0b00000001}},//01
    {.romcode = {0b00010001}},//11
    {.romcode = {0b00110001}},//31
    {.romcode = {0b00110101}},//35
    {.romcode = {0b01010001}},//51
    {.romcode = {0b10000000}},//80
    {.romcode = {0b10101010}},//aa
    {.romcode = {0b11110101}},//f5
    {.romcode = {0b11110111}},//f7
    {.romcode = {0xFF,0x00,0xFF,0x00,0x55,0x00,0xAA,0x00}},
    {.romcode = {0x12,0x34,0x56,0x78,0x9a,0xbc,0xde,0xf0}},
    {.romcode = {0x10,0x76,0xc7,0x04,0x01,0x08,0x00,0x71}}, // this is from a real 1-wire thermometer - checksum should be OK
};

void rom_device_reset(struct owunit *device)
{
    device->rompos = 0;
    device->state = 0;
    device->selected = true;
}

bool rom_device_read(struct owunit *device)
{
    if (!device->selected) return true;
    bool res = 0;
    if (device->state == 0) {
        device->state++;
        res = ow_code_getbit(device->romcode, device->rompos);
        return res;
    }
    if (device->state == 1) {
        device->state++;
        res = !ow_code_getbit(device->romcode, device->rompos);
        return res;
    }

    return res;
}

void rom_device_write(struct owunit *device, bool selectedbit)
{
    if (!device->selected) return;

    if (ow_code_getbit(device->romcode, device->rompos) != selectedbit) {
        device->selected = false;
    }
    else {
        device->rompos++;
        device->state = 0;
    }
}

bool ow_reset(void)
{
    for (int i = 0; i < UNITS_COUNT; ++i) {
        rom_device_reset(&units[i]);
    }
    return (UNITS_COUNT > 0);
}

bool ow_read_bit(void)
{
    bool bus = 1;
    for (int i = 0; i < UNITS_COUNT; ++i) {
        bus &= rom_device_read(&units[i]);
    }
    return bus;
}

void ow_write_bit(bool value)
{
    for (int i = 0; i < UNITS_COUNT; ++i) {
        rom_device_write(&units[i], value);
    }
}

void ow_write_u8(uint8_t value)
{
    (void) value;
    // Dummy, do nothing
}