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396 lines
12 KiB
396 lines
12 KiB
/*
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* SoftwareSerial.cpp (formerly NewSoftSerial.cpp)
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*
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* Multi-instance software serial library for Arduino/Wiring
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* -- Interrupt-driven receive and other improvements by ladyada
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* <https://ladyada.net>
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* -- Tuning, circular buffer, derivation from class Print/Stream,
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* multi-instance support, porting to 8MHz processors,
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* various optimizations, PROGMEM delay tables, inverse logic and
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* direct port writing by Mikal Hart <http://www.arduiniana.org>
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* -- Pin change interrupt macros by Paul Stoffregen <https://www.pjrc.com>
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* -- 20MHz processor support by Garrett Mace <http://www.macetech.com>
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* -- ATmega1280/2560 support by Brett Hagman <https://www.roguerobotics.com>
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* -- STM32 support by Armin van der Togt
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*
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* The latest version of this library can always be found at
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* http://arduiniana.org.
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*/
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//
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// Includes
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//
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#if defined(PLATFORMIO) && defined(ARDUINO_ARCH_STM32) && !defined(STM32GENERIC)
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#include "../../inc/MarlinConfig.h"
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#include "SoftwareSerial.h"
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#define OVERSAMPLE 3 // in RX, Timer will generate interruption OVERSAMPLE time during a bit. Thus OVERSAMPLE ticks in a bit. (interrupt not synchonized with edge).
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// defined in bit-periods
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#define HALFDUPLEX_SWITCH_DELAY 5
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// It's best to define TIMER_SERIAL in variant.h. If not defined, we choose one here
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// The order is based on (lack of) features and compare channels, we choose the simplest available
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// because we only need an update interrupt
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#if !defined(TIMER_SERIAL)
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#if defined(TIM18_BASE)
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#define TIMER_SERIAL TIM18
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#elif defined(TIM7_BASE)
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#define TIMER_SERIAL TIM7
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#elif defined(TIM6_BASE)
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#define TIMER_SERIAL TIM6
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#elif defined(TIM22_BASE)
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#define TIMER_SERIAL TIM22
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#elif defined(TIM21_BASE)
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#define TIMER_SERIAL TIM21
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#elif defined(TIM17_BASE)
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#define TIMER_SERIAL TIM17
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#elif defined(TIM16_BASE)
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#define TIMER_SERIAL TIM16
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#elif defined(TIM15_BASE)
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#define TIMER_SERIAL TIM15
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#elif defined(TIM14_BASE)
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#define TIMER_SERIAL TIM14
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#elif defined(TIM13_BASE)
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#define TIMER_SERIAL TIM13
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#elif defined(TIM11_BASE)
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#define TIMER_SERIAL TIM11
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#elif defined(TIM10_BASE)
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#define TIMER_SERIAL TIM10
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#elif defined(TIM12_BASE)
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#define TIMER_SERIAL TIM12
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#elif defined(TIM19_BASE)
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#define TIMER_SERIAL TIM19
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#elif defined(TIM9_BASE)
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#define TIMER_SERIAL TIM9
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#elif defined(TIM5_BASE)
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#define TIMER_SERIAL TIM5
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#elif defined(TIM4_BASE)
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#define TIMER_SERIAL TIM4
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#elif defined(TIM3_BASE)
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#define TIMER_SERIAL TIM3
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#elif defined(TIM2_BASE)
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#define TIMER_SERIAL TIM2
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#elif defined(TIM20_BASE)
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#define TIMER_SERIAL TIM20
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#elif defined(TIM8_BASE)
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#define TIMER_SERIAL TIM8
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#elif defined(TIM1_BASE)
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#define TIMER_SERIAL TIM1
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#else
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#error No suitable timer found for SoftwareSerial, define TIMER_SERIAL in variant.h
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#endif
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#endif
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//
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// Statics
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//
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HardwareTimer SoftwareSerial::timer(TIMER_SERIAL);
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const IRQn_Type SoftwareSerial::timer_interrupt_number = static_cast<IRQn_Type>(getTimerUpIrq(TIMER_SERIAL));
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uint32_t SoftwareSerial::timer_interrupt_priority = NVIC_EncodePriority(NVIC_GetPriorityGrouping(), TIM_IRQ_PRIO, TIM_IRQ_SUBPRIO);
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SoftwareSerial *SoftwareSerial::active_listener = nullptr;
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SoftwareSerial *volatile SoftwareSerial::active_out = nullptr;
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SoftwareSerial *volatile SoftwareSerial::active_in = nullptr;
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int32_t SoftwareSerial::tx_tick_cnt = 0; // OVERSAMPLE ticks needed for a bit
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int32_t volatile SoftwareSerial::rx_tick_cnt = 0; // OVERSAMPLE ticks needed for a bit
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uint32_t SoftwareSerial::tx_buffer = 0;
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int32_t SoftwareSerial::tx_bit_cnt = 0;
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uint32_t SoftwareSerial::rx_buffer = 0;
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int32_t SoftwareSerial::rx_bit_cnt = -1; // rx_bit_cnt = -1 : waiting for start bit
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uint32_t SoftwareSerial::cur_speed = 0;
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void SoftwareSerial::setInterruptPriority(uint32_t preemptPriority, uint32_t subPriority) {
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timer_interrupt_priority = NVIC_EncodePriority(NVIC_GetPriorityGrouping(), preemptPriority, subPriority);
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}
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//
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// Private methods
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//
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void SoftwareSerial::setSpeed(uint32_t speed) {
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if (speed != cur_speed) {
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timer.pause();
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if (speed != 0) {
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// Disable the timer
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uint32_t clock_rate, cmp_value;
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// Get timer clock
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clock_rate = timer.getTimerClkFreq();
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int pre = 1;
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// Calculate prescale an compare value
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do {
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cmp_value = clock_rate / (speed * OVERSAMPLE);
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if (cmp_value >= UINT16_MAX) {
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clock_rate /= 2;
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pre *= 2;
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}
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} while (cmp_value >= UINT16_MAX);
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timer.setPrescaleFactor(pre);
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timer.setOverflow(cmp_value);
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timer.setCount(0);
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timer.attachInterrupt(&handleInterrupt);
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timer.resume();
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NVIC_SetPriority(timer_interrupt_number, timer_interrupt_priority);
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}
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else
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timer.detachInterrupt();
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cur_speed = speed;
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}
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}
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// This function sets the current object as the "listening"
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// one and returns true if it replaces another
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bool SoftwareSerial::listen() {
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if (active_listener != this) {
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// wait for any transmit to complete as we may change speed
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while (active_out);
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active_listener->stopListening();
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rx_tick_cnt = 1; // 1 : next interrupt will decrease rx_tick_cnt to 0 which means RX pin level will be considered.
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rx_bit_cnt = -1; // rx_bit_cnt = -1 : waiting for start bit
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setSpeed(_speed);
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active_listener = this;
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if (!_half_duplex) active_in = this;
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return true;
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}
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return false;
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}
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// Stop listening. Returns true if we were actually listening.
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bool SoftwareSerial::stopListening() {
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if (active_listener == this) {
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// wait for any output to complete
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while (active_out);
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if (_half_duplex) setRXTX(false);
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active_listener = nullptr;
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active_in = nullptr;
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// turn off ints
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setSpeed(0);
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return true;
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}
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return false;
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}
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inline void SoftwareSerial::setTX() {
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if (_inverse_logic)
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LL_GPIO_ResetOutputPin(_transmitPinPort, _transmitPinNumber);
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else
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LL_GPIO_SetOutputPin(_transmitPinPort, _transmitPinNumber);
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pinMode(_transmitPin, OUTPUT);
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}
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inline void SoftwareSerial::setRX() {
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pinMode(_receivePin, _inverse_logic ? INPUT_PULLDOWN : INPUT_PULLUP); // pullup for normal logic!
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}
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inline void SoftwareSerial::setRXTX(bool input) {
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if (_half_duplex) {
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if (input) {
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if (active_in != this) {
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setRX();
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rx_bit_cnt = -1; // rx_bit_cnt = -1 : waiting for start bit
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rx_tick_cnt = 2; // 2 : next interrupt will be discarded. 2 interrupts required to consider RX pin level
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active_in = this;
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}
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}
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else {
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if (active_in == this) {
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setTX();
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active_in = nullptr;
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}
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}
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}
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}
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inline void SoftwareSerial::send() {
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if (--tx_tick_cnt <= 0) { // if tx_tick_cnt > 0 interrupt is discarded. Only when tx_tick_cnt reaches 0 is TX pin set.
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if (tx_bit_cnt++ < 10) { // tx_bit_cnt < 10 transmission is not finished (10 = 1 start +8 bits + 1 stop)
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// Send data (including start and stop bits)
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if (tx_buffer & 1)
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LL_GPIO_SetOutputPin(_transmitPinPort, _transmitPinNumber);
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else
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LL_GPIO_ResetOutputPin(_transmitPinPort, _transmitPinNumber);
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tx_buffer >>= 1;
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tx_tick_cnt = OVERSAMPLE; // Wait OVERSAMPLE ticks to send next bit
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}
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else { // Transmission finished
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tx_tick_cnt = 1;
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if (_output_pending) {
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active_out = nullptr;
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// In half-duplex mode wait HALFDUPLEX_SWITCH_DELAY bit-periods after the byte has
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// been transmitted before allowing the switch to RX mode
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}
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else if (tx_bit_cnt > 10 + OVERSAMPLE * HALFDUPLEX_SWITCH_DELAY) {
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if (_half_duplex && active_listener == this) setRXTX(true);
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active_out = nullptr;
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}
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}
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}
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}
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//
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// The receive routine called by the interrupt handler
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//
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inline void SoftwareSerial::recv() {
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if (--rx_tick_cnt <= 0) { // if rx_tick_cnt > 0 interrupt is discarded. Only when rx_tick_cnt reaches 0 is RX pin considered
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bool inbit = LL_GPIO_IsInputPinSet(_receivePinPort, _receivePinNumber) ^ _inverse_logic;
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if (rx_bit_cnt == -1) { // rx_bit_cnt = -1 : waiting for start bit
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if (!inbit) {
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// got start bit
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rx_bit_cnt = 0; // rx_bit_cnt == 0 : start bit received
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rx_tick_cnt = OVERSAMPLE + 1; // Wait 1 bit (OVERSAMPLE ticks) + 1 tick in order to sample RX pin in the middle of the edge (and not too close to the edge)
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rx_buffer = 0;
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}
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else
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rx_tick_cnt = 1; // Waiting for start bit, but wrong level. Wait for next Interrupt to check RX pin level
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}
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else if (rx_bit_cnt >= 8) { // rx_bit_cnt >= 8 : waiting for stop bit
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if (inbit) {
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// Stop-bit read complete. Add to buffer.
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uint8_t next = (_receive_buffer_tail + 1) % _SS_MAX_RX_BUFF;
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if (next != _receive_buffer_head) {
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// save new data in buffer: tail points to byte destination
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_receive_buffer[_receive_buffer_tail] = rx_buffer; // save new byte
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_receive_buffer_tail = next;
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}
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else // rx_bit_cnt = x with x = [0..7] correspond to new bit x received
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_buffer_overflow = true;
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}
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// Full trame received. Restart waiting for start bit at next interrupt
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rx_tick_cnt = 1;
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rx_bit_cnt = -1;
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}
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else {
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// data bits
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rx_buffer >>= 1;
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if (inbit) rx_buffer |= 0x80;
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rx_bit_cnt++; // Prepare for next bit
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rx_tick_cnt = OVERSAMPLE; // Wait OVERSAMPLE ticks before sampling next bit
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}
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}
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}
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//
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// Interrupt handling
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//
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/* static */
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inline void SoftwareSerial::handleInterrupt(HardwareTimer*) {
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if (active_in) active_in->recv();
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if (active_out) active_out->send();
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}
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//
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// Constructor
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//
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SoftwareSerial::SoftwareSerial(uint16_t receivePin, uint16_t transmitPin, bool inverse_logic /* = false */) :
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_receivePin(receivePin),
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_transmitPin(transmitPin),
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_receivePinPort(digitalPinToPort(receivePin)),
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_receivePinNumber(STM_LL_GPIO_PIN(digitalPinToPinName(receivePin))),
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_transmitPinPort(digitalPinToPort(transmitPin)),
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_transmitPinNumber(STM_LL_GPIO_PIN(digitalPinToPinName(transmitPin))),
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_speed(0),
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_buffer_overflow(false),
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_inverse_logic(inverse_logic),
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_half_duplex(receivePin == transmitPin),
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_output_pending(0),
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_receive_buffer_tail(0),
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_receive_buffer_head(0)
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{
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if ((receivePin < NUM_DIGITAL_PINS) || (transmitPin < NUM_DIGITAL_PINS)) {
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/* Enable GPIO clock for tx and rx pin*/
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set_GPIO_Port_Clock(STM_PORT(digitalPinToPinName(transmitPin)));
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set_GPIO_Port_Clock(STM_PORT(digitalPinToPinName(receivePin)));
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}
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else
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_Error_Handler("ERROR: invalid pin number\n", -1);
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}
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//
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// Destructor
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//
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SoftwareSerial::~SoftwareSerial() { end(); }
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//
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// Public methods
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//
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void SoftwareSerial::begin(long speed) {
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#ifdef FORCE_BAUD_RATE
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speed = FORCE_BAUD_RATE;
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#endif
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_speed = speed;
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if (!_half_duplex) {
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setTX();
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setRX();
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listen();
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}
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else
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setTX();
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}
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void SoftwareSerial::end() {
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stopListening();
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}
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// Read data from buffer
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int SoftwareSerial::read() {
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// Empty buffer?
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if (_receive_buffer_head == _receive_buffer_tail) return -1;
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// Read from "head"
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uint8_t d = _receive_buffer[_receive_buffer_head]; // grab next byte
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_receive_buffer_head = (_receive_buffer_head + 1) % _SS_MAX_RX_BUFF;
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return d;
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}
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int SoftwareSerial::available() {
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return (_receive_buffer_tail + _SS_MAX_RX_BUFF - _receive_buffer_head) % _SS_MAX_RX_BUFF;
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}
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size_t SoftwareSerial::write(uint8_t b) {
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// wait for previous transmit to complete
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_output_pending = 1;
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while (active_out) { /* nada */ }
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// add start and stop bits.
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tx_buffer = b << 1 | 0x200;
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if (_inverse_logic) tx_buffer = ~tx_buffer;
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tx_bit_cnt = 0;
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tx_tick_cnt = OVERSAMPLE;
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setSpeed(_speed);
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if (_half_duplex) setRXTX(false);
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_output_pending = 0;
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// make us active
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active_out = this;
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return 1;
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}
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void SoftwareSerial::flush() {
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noInterrupts();
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_receive_buffer_head = _receive_buffer_tail = 0;
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interrupts();
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}
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int SoftwareSerial::peek() {
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// Empty buffer?
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if (_receive_buffer_head == _receive_buffer_tail) return -1;
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// Read from "head"
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return _receive_buffer[_receive_buffer_head];
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}
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#endif // ARDUINO_ARCH_STM32 && !STM32GENERIC
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