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https://github.com/mytechnotalent/Embedded-Hacking.git
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93 lines
3.1 KiB
C
93 lines
3.1 KiB
C
/**
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* @file i2c.c
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* @brief Implementation of the I2C bus driver
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* @author Kevin Thomas
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* @date 2025
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*
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* MIT License
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*
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* Copyright (c) 2025 Kevin Thomas
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all
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* copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*/
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#include "i2c.h"
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#include <stdio.h>
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#include "pico/stdlib.h"
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#include "hardware/i2c.h"
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#include "hardware/gpio.h"
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/**
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* @brief Map an I2C port number to its hardware instance pointer
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*
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* @param port I2C port number (0 for i2c0, 1 for i2c1)
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* @return i2c_inst_t* Pointer to the corresponding I2C hardware instance
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*/
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static i2c_inst_t *_get_i2c_inst(uint8_t port) {
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return port == 0 ? i2c0 : i2c1;
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}
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void i2c_driver_init(uint8_t port, uint32_t sda_pin, uint32_t scl_pin,
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uint32_t baud_hz) {
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i2c_inst_t *inst = _get_i2c_inst(port);
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i2c_init(inst, baud_hz);
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gpio_set_function(sda_pin, GPIO_FUNC_I2C);
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gpio_set_function(scl_pin, GPIO_FUNC_I2C);
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gpio_pull_up(sda_pin);
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gpio_pull_up(scl_pin);
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}
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bool i2c_driver_probe(uint8_t port, uint8_t addr) {
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i2c_inst_t *inst = _get_i2c_inst(port);
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uint8_t dummy;
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return i2c_read_blocking(inst, addr, &dummy, 1, false) >= 0;
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}
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/**
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* @brief Print the I2C scan table header over UART
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*/
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static void _print_scan_header(void) {
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printf("\r\nI2C bus scan:\r\n");
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printf(" 0 1 2 3 4 5 6 7 8 9 A B C D E F\r\n");
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}
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/**
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* @brief Print one cell of the scan table for a given address
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*
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* Prints the row label when the address is at a 16-byte boundary, then
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* prints the address if a device responds, dashes if not, or blank if
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* the address is in the reserved range. Ends the row at every 16th address.
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*
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* @param port I2C port number (0 for i2c0, 1 for i2c1)
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* @param addr 7-bit I2C address being probed
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*/
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static void _print_scan_entry(uint8_t port, uint8_t addr) {
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if (addr % 16 == 0) printf("%02X: ", addr);
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if (addr < 0x08 || addr > 0x77) printf(" ");
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else if (i2c_driver_probe(port, addr)) printf("%02X ", addr);
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else printf("-- ");
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if (addr % 16 == 15) printf("\r\n");
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}
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void i2c_driver_scan(uint8_t port) {
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_print_scan_header();
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for (uint8_t addr = 0; addr < 128; addr++)
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_print_scan_entry(port, addr);
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}
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