mirror of
https://github.com/DCC-EX/CommandStation-EX.git
synced 2024-12-23 21:01:25 +01:00
266 lines
10 KiB
C
266 lines
10 KiB
C
/*
|
|
* © 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 <https://www.gnu.org/licenses/>.
|
|
*/
|
|
|
|
#ifndef I2CMANAGER_STM32_H
|
|
#define I2CMANAGER_STM32_H
|
|
|
|
#include <Arduino.h>
|
|
#include "I2CManager.h"
|
|
|
|
//#include <avr/io.h>
|
|
//#include <avr/interrupt.h>
|
|
#include <wiring_private.h>
|
|
|
|
/***************************************************************************
|
|
* 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;
|
|
#define I2C_IRQn I2C1_EV_IRQn
|
|
|
|
/***************************************************************************
|
|
* 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 CR2 Register in order to generate correct timings
|
|
s->CR2 |= (16<<0); // PCLK1 FREQUENCY in MHz
|
|
|
|
#if defined(I2C_USE_INTERRUPTS)
|
|
// Setting NVIC
|
|
NVIC_SetPriority(I2C_IRQn, 1); // Match default priorities
|
|
NVIC_EnableIRQ(I2C_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)
|
|
s->CR2 |= 0x0700; // Enable Buffer, Event and Error interrupts
|
|
#endif
|
|
|
|
// Calculate baudrate and set default rate for now
|
|
// 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
|
|
|
|
// Enable the I2C master mode
|
|
s->CR1 |= (1<<0); // Enable I2C
|
|
// 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;
|
|
uint8_t temp;
|
|
|
|
// 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 for read operation
|
|
s->CR1 |= (1<<10); // Enable the ACK
|
|
s->CR1 |= (1<<8); // Generate START
|
|
// Send address with read flag (1) or'd in
|
|
s->DR = (currentRequest->i2cAddress << 1) | 1; // send the address
|
|
while (!(s->SR1 & (1<<1))); // wait for ADDR bit to set
|
|
// Special case for 1 byte reads!
|
|
if (bytesToReceive == 1)
|
|
{
|
|
s->CR1 &= ~(1<<10); // clear the ACK bit
|
|
temp = I2C1->SR1 | I2C1->SR2; // read SR1 and SR2 to clear the ADDR bit.... EV6 condition
|
|
s->CR1 |= (1<<9); // Stop I2C
|
|
}
|
|
else
|
|
temp = s->SR1 | s->SR2; // read SR1 and SR2 to clear the ADDR bit
|
|
}
|
|
else {
|
|
// Send start for write operation
|
|
s->CR1 |= (1<<10); // Enable the ACK
|
|
s->CR1 |= (1<<8); // Generate START
|
|
// Send address with write flag (0) or'd in
|
|
s->DR = (currentRequest->i2cAddress << 1) | 0; // send the address
|
|
while (!(s->SR1 & (1<<1))); // wait for ADDR bit to set
|
|
temp = s->SR1 | s->SR2; // read SR1 and SR2 to clear the ADDR bit
|
|
}
|
|
}
|
|
|
|
/***************************************************************************
|
|
* Initiate a stop bit for transmission (does not interrupt)
|
|
***************************************************************************/
|
|
void I2CManagerClass::I2C_sendStop() {
|
|
s->CR1 |= (1<<9); // Stop I2C
|
|
}
|
|
|
|
/***************************************************************************
|
|
* Close I2C down
|
|
***************************************************************************/
|
|
void I2CManagerClass::I2C_close() {
|
|
I2C_sendStop();
|
|
// Disable the I2C master mode and wait for sync
|
|
s->CR1 &= ~(1<<0); // Disable I2C peripheral
|
|
// Should never happen, but wait for up to 500us only.
|
|
unsigned long startTime = micros();
|
|
while ((s->CR1 && 1) != 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->SR1 && (1<<9)) {
|
|
// Arbitration lost, restart
|
|
I2C_sendStart(); // Reinitiate request
|
|
} else if (s->SR1 && (1<<8)) {
|
|
// Bus error
|
|
state = I2C_STATUS_BUS_ERROR;
|
|
} else if (s->SR1 && (1<<7)) {
|
|
// Master write completed
|
|
if (s->SR1 && (1<<10)) {
|
|
// Nacked, send stop.
|
|
I2C_sendStop();
|
|
state = I2C_STATUS_NEGATIVE_ACKNOWLEDGE;
|
|
} else if (bytesToSend) {
|
|
// Acked, so send next byte
|
|
s->DR = 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 {
|
|
// Check both TxE/BTF == 1 before generating stop
|
|
while (!(s->SR1 && (1<<7))); // Check TxE
|
|
while (!(s->SR1 && (1<<2))); // Check BTF
|
|
// No more data to send/receive. Initiate a STOP condition.
|
|
I2C_sendStop();
|
|
state = I2C_STATUS_OK; // Done
|
|
}
|
|
} else if (s->SR1 && (1<<6)) {
|
|
// 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->DR; // 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->DR; // Store received byte
|
|
bytesToReceive--;
|
|
}
|
|
}
|
|
}
|
|
|
|
#endif /* I2CMANAGER_STM32_H */
|