From 3fbcd6f300c3477d93d2c5a20ba2141c63decd08 Mon Sep 17 00:00:00 2001 From: pmantoine Date: Wed, 8 Feb 2023 10:04:18 +0800 Subject: [PATCH] STM32 native I2C driver initial edits --- I2CManager.cpp | 3 + I2CManager_STM32.h | 244 +++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 247 insertions(+) create mode 100644 I2CManager_STM32.h diff --git a/I2CManager.cpp b/I2CManager.cpp index 00aa71b..564c7b0 100644 --- a/I2CManager.cpp +++ b/I2CManager.cpp @@ -35,6 +35,9 @@ #elif defined(ARDUINO_ARCH_SAMD) #include "I2CManager_NonBlocking.h" #include "I2CManager_SAMD.h" // SAMD21 for now... SAMD51 as well later +#elif defined(ARDUINO_ARCH_STM32) +#include "I2CManager_NonBlocking.h" +#include "I2CManager_STM32.h" // STM32F411RE for now... more later #else #define I2C_USE_WIRE #include "I2CManager_Wire.h" // Other platforms diff --git a/I2CManager_STM32.h b/I2CManager_STM32.h new file mode 100644 index 0000000..0e944e7 --- /dev/null +++ b/I2CManager_STM32.h @@ -0,0 +1,244 @@ +/* + * © 2022-23 Paul M Antoine + * © 2023, Neil McKechnie + * All rights reserved. + * + * This file is part of CommandStation-EX + * + * This 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. + * + * It 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 CommandStation. If not, see . + */ + +#ifndef I2CMANAGER_STM32_H +#define I2CMANAGER_STM32_H + +#include +#include "I2CManager.h" + +//#include +//#include +#include + +/*************************************************************************** + * Interrupt handler. + * IRQ handler for SERCOM3 which is the default I2C definition for Arduino Zero + * compatible variants such as the Sparkfun SAMD21 Dev Breakout etc. + * Later we may wish to allow use of an alternate I2C bus, or more than one I2C + * bus on the SAMD architecture + ***************************************************************************/ +#if defined(I2C_USE_INTERRUPTS) && defined(ARDUINO_ARCH_STM32) +void I2C1_IRQHandler() { + I2CManagerClass::handleInterrupt(); +} +#endif + +// Assume I2C1 for now - default I2C bus on Nucleo-F411RE and likely Nucleo-64 variants +I2C_TypeDef *s = I2C1; + +/*************************************************************************** + * Set I2C clock speed register. This should only be called outside of + * a transmission. The I2CManagerClass::_setClock() function ensures + * that it is only called at the beginning of an I2C transaction. + ***************************************************************************/ +void I2CManagerClass::I2C_setClock(uint32_t i2cClockSpeed) { + + // Calculate a rise time appropriate to the requested bus speed + int t_rise; + if (i2cClockSpeed < 200000L) { + i2cClockSpeed = 100000L; + t_rise = 1000; + } else if (i2cClockSpeed < 800000L) { + i2cClockSpeed = 400000L; + t_rise = 300; + } else if (i2cClockSpeed < 1200000L) { + i2cClockSpeed = 1000000L; + t_rise = 120; + } else { + i2cClockSpeed = 100000L; + t_rise = 1000; + } + + + // Disable the I2C master mode and wait for sync + // s->I2CM.CTRLA.bit.ENABLE = 0 ; + // while (s->I2CM.SYNCBUSY.bit.ENABLE != 0); + + // Calculate baudrate - using a rise time appropriate for the speed + // s->I2CM.BAUD.bit.BAUD = SystemCoreClock / (2 * i2cClockSpeed) - 5 - (((SystemCoreClock / 1000000) * t_rise) / (2 * 1000)); + + // Enable the I2C master mode and wait for sync + // s->I2CM.CTRLA.bit.ENABLE = 1 ; + // while (s->I2CM.SYNCBUSY.bit.ENABLE != 0); + + // Setting bus idle mode and wait for sync + // s->I2CM.STATUS.bit.BUSSTATE = 1 ; + // while (s->I2CM.SYNCBUSY.bit.SYSOP != 0); +} + +/*************************************************************************** + * Initialise I2C registers. + ***************************************************************************/ +void I2CManagerClass::I2C_init() +{ + //Setting up the clocks + RCC->APB1ENR |= (1<<21); // Enable I2C CLOCK + RCC->AHB1ENR |= (1<<1); // Enable GPIOB CLOCK for PB8/PB9 + // Standard I2C pins are SCL on PB8 and SDA on PB9 + // Bits (17:16)= 1:0 --> Alternate Function for Pin PB8; + // Bits (19:18)= 1:0 --> Alternate Function for Pin PB9 + GPIOB->MODER |= (2<<(8*2)) | (2<<(9*2)); // PB8 and PB9 set to ALT function + GPIOB->OTYPER |= (1<<8) | (1<<9); // PB8 and PB9 set to open drain output capability + GPIOB->OSPEEDR |= (3<<(8*2)) | (3<<(9*2)); // PB8 and PB9 set to High Speed mode + GPIOB->PUPDR |= (1<<(8*2)) | (1<<(9*2)); // PB8 and PB9 set to pull-up capability + // Alt Function High register routing pins PB8 and PB9 for I2C1: + // Bits (3:2:1:0) = 0:1:0:0 --> AF4 for pin PB8 + // Bits (7:6:5:4) = 0:1:0:0 --> AF4 for pin PB9 + GPIOB->AFR[1] |= (4<<0) | (4<<4); // PB8 on low nibble, PB9 on next nibble up + + // Software reset the I2C peripheral + s->CR1 |= (1<<15); // reset the I2C + s->CR1 &= ~(1<<15); // Normal operation + + // Program the peripheral input clock in I2C_CR2 Register in order to generate correct timings + s->CR2 |= (16<<0); // PCLK1 FREQUENCY in MHz + + // Configure the Clock Control Register for 100KHz SCL frequency + // Bit 15: I2C Master mode, 0=standard, 1=Fast Mode + // Bit 14: Duty, fast mode duty cycle + // Bit 11-0: FREQR = 16MHz => TPCLK1 = 62.5ns, so CCR divisor must be 0x50 (80 * 62.5ns = 5000ns) + s->CCR = 0x0050; + + // Configure the rise time register - max allowed in 1000ns + s->TRISE = 0x0011; // 1000 ns / 62.5 ns = 16 + 1 + +#if defined(I2C_USE_INTERRUPTS) + // Setting NVIC + NVIC_SetPriority(I2C1_EV_IRQn, 1); // Match default priorities + NVIC_EnableIRQ(I2C1_EV_IRQn); + + // CR2 Interrupt Settings + // Bit 15-13: reserved + // Bit 12: LAST - DMA last transfer + // Bit 11: DMAEN - DMA enable + // Bit 10: ITBUFEN - Buffer interrupt enable + // Bit 9: ITEVTEN - Event interrupt enable + // Bit 8: ITERREN - Error interrupt enable + // Bit 7-6: reserved + // Bit 5-0: FREQ - Peripheral clock frequency (max 50MHz) + // Enable all interrupts + s->CR2 |= 0x0700; +#endif + + // Calculate baudrate and set default rate for now + + // Enable the I2C master mode and wait for sync + + // Setting bus idle mode and wait for sync +} + +/*************************************************************************** + * Initiate a start bit for transmission. + ***************************************************************************/ +void I2CManagerClass::I2C_sendStart() { + + // Set counters here in case this is a retry. + bytesToSend = currentRequest->writeLen; + bytesToReceive = currentRequest->readLen; + + // On a single-master I2C bus, the start bit won't be sent until the bus + // state goes to IDLE so we can request it without waiting. On a + // multi-master bus, the bus may be BUSY under control of another master, + // in which case we can avoid some arbitration failures by waiting until + // the bus state is IDLE. We don't do that here. + + // If anything to send, initiate write. Otherwise initiate read. + if (operation == OPERATION_READ || ((operation == OPERATION_REQUEST) && !bytesToSend)) + { + // Send start and address with read flag (1) or'd in + // s->I2CM.ADDR.bit.ADDR = (currentRequest->i2cAddress << 1) | 1; + } + else { + // Send start and address with write flag (0) or'd in + // s->I2CM.ADDR.bit.ADDR = (currentRequest->i2cAddress << 1ul) | 0; + } +} + +/*************************************************************************** + * Initiate a stop bit for transmission (does not interrupt) + ***************************************************************************/ +void I2CManagerClass::I2C_sendStop() { + // s->I2CM.CTRLB.bit.CMD = 3; // Stop condition +} + +/*************************************************************************** + * Close I2C down + ***************************************************************************/ +void I2CManagerClass::I2C_close() { + I2C_sendStop(); + // Disable the I2C master mode and wait for sync + // s->I2CM.CTRLA.bit.ENABLE = 0 ; + // Wait for up to 500us only. + unsigned long startTime = micros(); + // while (s->I2CM.SYNCBUSY.bit.ENABLE != 0) { + // if (micros() - startTime >= 500UL) break; + // } +} + +/*************************************************************************** + * Main state machine for I2C, called from interrupt handler or, + * if I2C_USE_INTERRUPTS isn't defined, from the I2CManagerClass::loop() function + * (and therefore, indirectly, from I2CRB::wait() and I2CRB::isBusy()). + ***************************************************************************/ +void I2CManagerClass::I2C_handleInterrupt() { + + if (s->I2CM.STATUS.bit.ARBLOST) { + // Arbitration lost, restart + I2C_sendStart(); // Reinitiate request + } else if (s->I2CM.STATUS.bit.BUSERR) { + // Bus error + state = I2C_STATUS_BUS_ERROR; + } else if (s->I2CM.INTFLAG.bit.MB) { + // Master write completed + if (s->I2CM.STATUS.bit.RXNACK) { + // Nacked, send stop. + I2C_sendStop(); + state = I2C_STATUS_NEGATIVE_ACKNOWLEDGE; + } else if (bytesToSend) { + // Acked, so send next byte + s->I2CM.DATA.bit.DATA = currentRequest->writeBuffer[txCount++]; + bytesToSend--; + } else if (bytesToReceive) { + // Last sent byte acked and no more to send. Send repeated start, address and read bit. + s->I2CM.ADDR.bit.ADDR = (currentRequest->i2cAddress << 1) | 1; + } else { + // No more data to send/receive. Initiate a STOP condition. + I2C_sendStop(); + state = I2C_STATUS_OK; // Done + } + } else if (s->I2CM.INTFLAG.bit.SB) { + // Master read completed without errors + if (bytesToReceive == 1) { + s->I2CM.CTRLB.bit.ACKACT = 1; // NAK final byte + I2C_sendStop(); // send stop + currentRequest->readBuffer[rxCount++] = s->I2CM.DATA.bit.DATA; // Store received byte + bytesToReceive = 0; + state = I2C_STATUS_OK; // done + } else if (bytesToReceive) { + s->I2CM.CTRLB.bit.ACKACT = 0; // ACK all but final byte + currentRequest->readBuffer[rxCount++] = s->I2CM.DATA.bit.DATA; // Store received byte + bytesToReceive--; + } + } +} + +#endif /* I2CMANAGER_STM32_H */