/**
 * Copyright (c) 2020 Raspberry Pi (Trading) Ltd.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

// Sweep through all 7-bit I2C addresses, to see if any slaves are present on
// the I2C bus. Print out a table that looks like this:
//
// I2C Bus Scan
//    0 1 2 3 4 5 6 7 8 9 A B C D E F
// 00 . . . . . . . . . . . . . . . .
// 10 . . @ . . . . . . . . . . . . .
// 20 . . . . . . . . . . . . . . . .
// 30 . . . . @ . . . . . . . . . . .
// 40 . . . . . . . . . . . . . . . .
// 50 . . . . . . . . . . . . . . . .
// 60 . . . . . . . . . . . . . . . .
// 70 . . . . . . . . . . . . . . . .
// E.g. if addresses 0x12 and 0x34 were acknowledged.

#include <stdio.h>
#include "pico/stdlib.h"
#include "pico/binary_info.h"
#include "hardware/i2c.h"
#include "pico/stdlib.h"
#include "hardware/spi.h"
#include "hardware/i2c.h"
#include "hardware/dma.h"
#include "hardware/pio.h"
#include "hardware/interp.h"
#include "hardware/timer.h"
#include "hardware/pwm.h"
#include "hardware/clocks.h"
#include "hardware/uart.h"
// I2C reserves some addresses for special purposes. We exclude these from the scan.
// These are any addresses of the form 000 0xxx or 111 1xxx
bool reserved_addr(uint8_t addr) {
    return (addr & 0x78) == 0 || (addr & 0x78) == 0x78;
}
#define PICO_DEFAULT_I2C_SDA_PIN 22
#define PICO_DEFAULT_I2C_SCL_PIN 19
int main() {
    // Enable UART so we can print status output
    stdio_init_all();
#if !defined(i2c_default) || !defined(PICO_DEFAULT_I2C_SDA_PIN) || !defined(PICO_DEFAULT_I2C_SCL_PIN)
#warning i2c/bus_scan example requires a board with I2C pins
    puts("Default I2C pins were not defined");
#else
    // This example will use I2C0 on the default SDA and SCL pins (GP4, GP5 on a Pico)
    gpio_set_function(11, GPIO_FUNC_PWM);
    uint slice_num = pwm_gpio_to_slice_num(11);
    // 6 cycles (0 to 5), 125 MHz / 6 = ~20.83 MHz wrap rate
    pwm_set_wrap(slice_num, 5);
    pwm_set_gpio_level(11, 3);
    pwm_set_enabled(slice_num, true);
    sleep_ms(1000);

    i2c_init(i2c1, 100 * 1000);
    gpio_set_function(22, GPIO_FUNC_I2C);
    gpio_set_function(19, GPIO_FUNC_I2C);
    gpio_pull_up(22);
    gpio_pull_up(19);
    // Make the I2C pins available to picotool
    bi_decl(bi_2pins_with_func(22, 19, GPIO_FUNC_I2C));
    while(true){
        printf("\nI2C Bus Scan\n");
        printf("   0  1  2  3  4  5  6  7  8  9  A  B  C  D  E  F\n");

        for (int addr = 0; addr < (1 << 7); ++addr) {
            if (addr % 16 == 0) {
                printf("%02x ", addr);
            }

            // Perform a 1-byte dummy read from the probe address. If a slave
            // acknowledges this address, the function returns the number of bytes
            // transferred. If the address byte is ignored, the function returns
            // -1.

            // Skip over any reserved addresses.
            int ret;
            uint8_t rxdata;
            if (reserved_addr(addr))
                ret = PICO_ERROR_GENERIC;
            else
                ret = i2c_read_blocking(i2c1, addr, &rxdata, 1, false);
                

            printf(ret < 0 ? "." : "@");
            printf(addr % 16 == 15 ? "\n" : "  ");
        }
        printf("Done.\n");
        sleep_ms(1000);
    }

    return 0;
#endif
}