Revert "Add I2C slave library & example"

examples/i2c_slave/Makefile

-all : flash
-
-TARGET:=i2c_slave_example
-
-include ../../ch32v003fun/ch32v003fun.mk
-
-flash : cv_flash
-clean : cv_clean
-

examples/i2c_slave/README.md

-# I2C peripheral in slave mode
-
-This library and example show how to use the I2C peripheral in slave mode.
-
-The library uses a one-byte address, allowing for up to 256 registers to be defined.
-
-The first byte written to the device within a transaction determines the offset for following reads and writes, emulating a simple EEPROM.
-
-The example will turn on a LED connected to PD0 when the LSB of register 0 is set to 1 and off when it's set to 0.

examples/i2c_slave/i2c_slave.h

-/*
- * Single-File-Header for using the I2C peripheral in slave mode
- *
- * MIT License
- *
- * Copyright (c) 2023 Renze Nicolai
- *
- * Permission is hereby granted, free of charge, to any person obtaining a copy
- * of this software and associated documentation files (the "Software"), to deal
- * in the Software without restriction, including without limitation the rights
- * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- * copies of the Software, and to permit persons to whom the Software is
- * furnished to do so, subject to the following conditions:
- *
- * The above copyright notice and this permission notice shall be included in all
- * copies or substantial portions of the Software.
- *
- * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
- * SOFTWARE.
- */
-
-#ifndef __I2C_SLAVE_H
-#define __I2C_SLAVE_H
-
-#include <stdint.h>
-
-#define APB_CLOCK SYSTEM_CORE_CLOCK
-
-struct _i2c_slave_state {
-    uint8_t first_write;
-    uint8_t offset;
-    uint8_t position;
-    volatile uint8_t* volatile registers;
-    uint8_t size;
-} i2c_slave_state;
-
-void SetupI2CSlave(uint8_t address, volatile uint8_t* registers, uint8_t size) {
-    i2c_slave_state.first_write = 1;
-    i2c_slave_state.offset = 0;
-    i2c_slave_state.position = 0;
-    i2c_slave_state.registers = registers;
-    i2c_slave_state.size = size;
-
-    // Enable GPIOC and I2C
-    RCC->APB2PCENR |= RCC_APB2Periph_GPIOC;
-    RCC->APB1PCENR |= RCC_APB1Periph_I2C1;
-
-    // PC1 is SDA, 10MHz Output, alt func, open-drain
-    GPIOC->CFGLR &= ~(0xf<<(4*1));
-    GPIOC->CFGLR |= (GPIO_Speed_10MHz | GPIO_CNF_OUT_OD_AF)<<(4*1);
-
-    // PC2 is SCL, 10MHz Output, alt func, open-drain
-    GPIOC->CFGLR &= ~(0xf<<(4*2));
-    GPIOC->CFGLR |= (GPIO_Speed_10MHz | GPIO_CNF_OUT_OD_AF)<<(4*2);
-
-    // Reset I2C1 to init all regs
-    RCC->APB1PRSTR |= RCC_APB1Periph_I2C1;
-    RCC->APB1PRSTR &= ~RCC_APB1Periph_I2C1;
-
-    I2C1->CTLR1 |= I2C_CTLR1_SWRST;
-    I2C1->CTLR1 &= ~I2C_CTLR1_SWRST;
-
-    // Set module clock frequency
-    uint32_t prerate = 2000000; // I2C Logic clock rate, must be higher than the bus clock rate
-    I2C1->CTLR2 |= (APB_CLOCK/prerate) & I2C_CTLR2_FREQ;
-
-    // Enable interrupts
-    I2C1->CTLR2 |= I2C_CTLR2_ITBUFEN;
-    I2C1->CTLR2 |= I2C_CTLR2_ITEVTEN; // Event interrupt
-    I2C1->CTLR2 |= I2C_CTLR2_ITERREN; // Error interrupt
-
-    NVIC_EnableIRQ(I2C1_EV_IRQn); // Event interrupt
-    NVIC_SetPriority(I2C1_EV_IRQn, 2 << 4);
-    NVIC_EnableIRQ(I2C1_ER_IRQn); // Error interrupt
-
-    // Set clock configuration
-    uint32_t clockrate = 1000000; // I2C Bus clock rate, must be lower than the logic clock rate
-    I2C1->CKCFGR = ((APB_CLOCK/(3*clockrate))&I2C_CKCFGR_CCR) | I2C_CKCFGR_FS; // Fast mode 33% duty cycle
-    //I2C1->CKCFGR = ((APB_CLOCK/(25*clockrate))&I2C_CKCFGR_CCR) | I2C_CKCFGR_DUTY | I2C_CKCFGR_FS; // Fast mode 36% duty cycle
-    //I2C1->CKCFGR = (APB_CLOCK/(2*clockrate))&I2C_CKCFGR_CCR; // Standard mode good to 100kHz
-
-    // Set I2C address
-    I2C1->OADDR1 = address << 1;
-
-    // Enable I2C
-    I2C1->CTLR1 |= I2C_CTLR1_PE;
-
-    // Acknowledge the first address match event when it happens
-    I2C1->CTLR1 |= I2C_CTLR1_ACK;
-}
-
-void I2C1_EV_IRQHandler(void) __attribute__((interrupt));
-void I2C1_EV_IRQHandler(void) {
-    uint16_t STAR1, STAR2 __attribute__((unused));
-    STAR1 = I2C1->STAR1;
-    STAR2 = I2C1->STAR2;
-
-    I2C1->CTLR1 |= I2C_CTLR1_ACK;
-
-    if (STAR1 & I2C_STAR1_ADDR) { // Start event
-        i2c_slave_state.first_write = 1; // Next write will be the offset
-        i2c_slave_state.position = i2c_slave_state.offset; // Reset position
-    }
-
-    if (STAR1 & I2C_STAR1_RXNE) { // Write event
-        if (i2c_slave_state.first_write) { // First byte written, set the offset
-            i2c_slave_state.offset = I2C1->DATAR;
-            i2c_slave_state.position = i2c_slave_state.offset;
-            i2c_slave_state.first_write = 0;
-        } else { // Normal register write
-            if (i2c_slave_state.position < i2c_slave_state.size) {
-                i2c_slave_state.registers[i2c_slave_state.position] = I2C1->DATAR;
-                i2c_slave_state.position++;
-            }
-        }
-    }
-
-    if (STAR1 & I2C_STAR1_TXE) { // Read event
-        if (i2c_slave_state.position < i2c_slave_state.size) {
-            I2C1->DATAR = i2c_slave_state.registers[i2c_slave_state.position];
-            i2c_slave_state.position++;
-        } else {
-            I2C1->DATAR = 0x00;
-        }
-    }
-}
-
-void I2C1_ER_IRQHandler(void) __attribute__((interrupt));
-void I2C1_ER_IRQHandler(void) {
-    uint16_t STAR1 = I2C1->STAR1;
-
-    if (STAR1 & I2C_STAR1_BERR) { // Bus error
-        I2C1->STAR1 &= ~(I2C_STAR1_BERR); // Clear error
-    }
-
-    if (STAR1 & I2C_STAR1_ARLO) { // Arbitration lost error
-        I2C1->STAR1 &= ~(I2C_STAR1_ARLO); // Clear error
-    }
-
-    if (STAR1 & I2C_STAR1_AF) { // Acknowledge failure
-        I2C1->STAR1 &= ~(I2C_STAR1_AF); // Clear error
-    }
-}
-
-#endif

examples/i2c_slave/i2c_slave_example.c

-#define SYSTEM_CORE_CLOCK 48000000
-
-#include "ch32v003fun.h"
-#include "i2c_slave.h"
-#include <stdio.h>
-
-// The I2C slave library uses a one byte address so you can extend the size of this array up to 256 registers
-// note that the register set is modified by interrupts, to prevent the compiler from accidently optimizing stuff
-// away make sure to declare the register array volatile
-
-volatile uint8_t i2c_registers[32] = {0x00};
-
-int main() {
-    SystemInit48HSI();
-    SetupDebugPrintf();
-    SetupI2CSlave(0x9, i2c_registers, sizeof(i2c_registers));
-
-    // Enable GPIOD and set pin 0 to output
-    RCC->APB2PCENR |= RCC_APB2Periph_GPIOD;
-    GPIOD->CFGLR &= ~(0xf<<(4*0));
-    GPIOD->CFGLR |= (GPIO_Speed_10MHz | GPIO_CNF_OUT_PP)<<(4*0);
-
-    while (1) {
-        if (i2c_registers[0] & 1) { // Turn on LED (PD0) if bit 1 of register 0 is set
-            GPIOD-> BSHR |= 1 << 16;
-        } else {
-            GPIOD-> BSHR |= 1;
-        }
-    }
-}