I2C works

F0:F030,F042,F072/usbcan_gpio/i2c.c

@@ -0,0 +1,214 @@
+/*
+ * This file is part of the usbcangpio project.
+ * Copyright 2026 Edward V. Emelianov <edward.emelianoff@gmail.com>.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "gpio.h"
+#include "i2c.h"
+
+// fields position in I2C1->TIMINGR
+#define I2C_TIMINGR_PRESC_Pos   28
+#define I2C_TIMINGR_SCLDEL_Pos  20
+#define I2C_TIMINGR_SDADEL_Pos  16
+#define I2C_TIMINGR_SCLH_Pos    8
+#define I2C_TIMINGR_SCLL_Pos    0
+
+i2c_speed_t curI2Cspeed = I2C_SPEED_10K;
+extern volatile uint32_t Tms;
+static uint32_t cntr;
+volatile uint8_t I2C_scan_mode = 0; // == 1 when I2C is in scan mode
+static uint8_t i2caddr  = I2C_ADDREND; // address for `scan`, not active
+
+void i2c_setup(i2c_speed_t speed){
+    if(speed >= I2C_SPEED_1M) speed = curI2Cspeed;
+    else curI2Cspeed = speed;
+    uint8_t PRESC, SCLDEL = 4, SDADEL = 2, SCLH, SCLL;
+    I2C1->CR1 = 0;
+    // I2C
+    RCC->CFGR3 |= RCC_CFGR3_I2C1SW; // use sysclock for timing
+    switch(curI2Cspeed){
+        case I2C_SPEED_10K:
+            PRESC = 0x0B;
+            SCLH = 0xC3;
+            SCLL = 0xC7;
+            break;
+        case I2C_SPEED_100K:
+            PRESC = 0x0B;
+            SCLH = 0x0F;
+            SCLL = 0x13;
+            break;
+        case I2C_SPEED_400K:
+            SDADEL = 3;
+            SCLDEL = 3;
+            PRESC = 5;
+            SCLH = 3;
+            SCLL = 9;
+            break;
+        case I2C_SPEED_1M:
+        default:
+            SDADEL = 0;
+            SCLDEL = 1;
+            PRESC = 5;
+            SCLH = 1;
+            SCLL = 3;
+            break;
+    }
+    I2C1->TIMINGR = (PRESC<<I2C_TIMINGR_PRESC_Pos) | (SCLDEL<<I2C_TIMINGR_SCLDEL_Pos) |
+                    (SDADEL<<I2C_TIMINGR_SDADEL_Pos) | (SCLH<<I2C_TIMINGR_SCLH_Pos) | (SCLL<< I2C_TIMINGR_SCLL_Pos);
+    if(speed < I2C_SPEED_400K){
+        SYSCFG->CFGR1 &= ~SYSCFG_CFGR1_I2C_FMP_I2C1;
+    }else{ // activate FM+
+        SYSCFG->CFGR1 |= SYSCFG_CFGR1_I2C_FMP_I2C1;
+    }
+    I2C1->ICR = 0xffff; // clear all errors
+    I2C1->CR1 = I2C_CR1_PE;
+}
+
+void i2c_stop(){
+    I2C1->CR1 = 0;
+}
+
+/**
+ * write command byte to I2C
+ * @param addr - device address (TSYS01_ADDR0 or TSYS01_ADDR1)
+ * @param data - bytes to write
+ * @param nbytes - amount of bytes to write
+ * @param stop - to set STOP
+ * @return 0 if error
+ */
+static uint8_t i2c_writes(uint8_t addr, uint8_t *data, uint8_t nbytes, uint8_t stop){
+    cntr = Tms;
+    I2C1->CR1 = 0; // clear busy flag
+    I2C1->ICR = 0x3f38; // clear all errors
+    I2C1->CR1 = I2C_CR1_PE;
+    while(I2C1->ISR & I2C_ISR_BUSY){
+        IWDG->KR = IWDG_REFRESH;
+        if(Tms - cntr > I2C_TIMEOUT){
+            DBG("Line busy\n");
+            return 0;  // check busy
+    }}
+    cntr = Tms;
+    while(I2C1->CR2 & I2C_CR2_START){
+        IWDG->KR = IWDG_REFRESH;
+        if(Tms - cntr > I2C_TIMEOUT){
+        return 0; // check start
+    }}
+    //I2C1->ICR = 0x3f38; // clear all errors
+    I2C1->CR2 = nbytes << 16 | addr;
+    if(stop) I2C1->CR2 |= I2C_CR2_AUTOEND; // autoend
+    // now start transfer
+    I2C1->CR2 |= I2C_CR2_START;
+    for(int i = 0; i < nbytes; ++i){
+        cntr = Tms;
+        while(!(I2C1->ISR & I2C_ISR_TXIS)){ // ready to transmit
+            IWDG->KR = IWDG_REFRESH;
+            if(I2C1->ISR & I2C_ISR_NACKF){
+                I2C1->ICR |= I2C_ICR_NACKCF;
+                DBG("NAK\n");
+                return 0;
+            }
+            if(Tms - cntr > I2C_TIMEOUT){
+                DBG("Timeout\n");
+                return 0;
+            }
+        }
+        I2C1->TXDR = data[i]; // send data
+    }
+    // wait for data gone
+    while(I2C1->ISR & I2C_ISR_BUSY){
+        IWDG->KR = IWDG_REFRESH;
+        if(Tms - cntr > I2C_TIMEOUT){break;}
+    }
+    return 1;
+}
+
+uint8_t i2c_write(uint8_t addr, uint8_t *data, uint8_t nbytes){
+    return i2c_writes(addr, data, nbytes, 1);
+}
+
+/**
+ * read nbytes of data from I2C line
+ * `data` should be an array with at least `nbytes` length
+ * @return 1 if all OK, 0 if NACK or no device found
+ */
+static uint8_t i2c_readb(uint8_t addr, uint8_t *data, uint8_t nbytes, uint8_t busychk){
+    if(busychk){
+        cntr = Tms;
+        while(I2C1->ISR & I2C_ISR_BUSY){
+            IWDG->KR = IWDG_REFRESH;
+            if(Tms - cntr > I2C_TIMEOUT){
+                DBG("Line busy\n");
+                return 0;  // check busy
+        }}
+    }
+    cntr = Tms;
+    while(I2C1->CR2 & I2C_CR2_START){
+        IWDG->KR = IWDG_REFRESH;
+        if(Tms - cntr > I2C_TIMEOUT){
+            DBG("No start\n");
+            return 0; // check start
+    }}
+    // read N bytes
+    I2C1->CR2 = (nbytes<<16) | addr | 1 | I2C_CR2_AUTOEND | I2C_CR2_RD_WRN;
+    I2C1->CR2 |= I2C_CR2_START;
+    uint8_t i;
+    for(i = 0; i < nbytes; ++i){
+        cntr = Tms;
+        while(!(I2C1->ISR & I2C_ISR_RXNE)){ // wait for data
+            IWDG->KR = IWDG_REFRESH;
+            if(I2C1->ISR & I2C_ISR_NACKF){
+                I2C1->ICR |= I2C_ICR_NACKCF;
+                DBG("NAK\n");
+                return 0;
+            }
+            if(Tms - cntr > I2C_TIMEOUT){
+                DBG("Timeout\n");
+                return 0;
+            }
+        }
+        *data++ = I2C1->RXDR;
+    }
+    return 1;
+ }
+
+uint8_t i2c_read(uint8_t addr, uint8_t *data, uint8_t nbytes){
+    return i2c_readb(addr, data, nbytes, 1);
+}
+
+// read register reg
+uint8_t i2c_read_reg(uint8_t addr, uint8_t reg, uint8_t *data, uint8_t nbytes){
+    if(!i2c_writes(addr, &reg, 1, 0)) return 0;
+    return i2c_readb(addr, data, nbytes, 0);
+}
+
+void i2c_init_scan_mode(){
+    i2caddr = 1;
+    I2C_scan_mode = 1;
+}
+
+// return 1 if next addr is active & return in as `addr`
+// if addresses are over, return 1 and set addr to I2C_NOADDR
+// if scan mode inactive, return 0 and set addr to I2C_NOADDR
+int i2c_scan_next_addr(uint8_t *addr){
+    *addr = i2caddr;
+    if(i2caddr == I2C_ADDREND){
+        *addr = I2C_ADDREND;
+        I2C_scan_mode = 0;
+        return 0;
+    }
+    if(!i2c_read_reg((i2caddr++)<<1, 0, NULL, 0)) return 0;
+    return 1;
+}