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8c01516f8a
* Allow unaligned input/output to SPI::transferBytes Fixes #4967 Support any alignment of input and output pointers and transfer lengths in SPI::transferBytes. Use 32-bit transfers and FIFO as much as possible. * Refactor misaligned transfer, avoid RMW to FIFO The SPI FIFO can't properly do RMW (i.e. bytewise updates) because when you read the FIFO you are actually reading the SPI read data, not what was written into the write FIFO. Refactor the transferBytes to take account of this. For aligned input and outputs, perform as before (but handle non-x4 sizes properly). For misaligned inputs, if it's unidirectional then do bytewise until the direction data pointer is aligned and then do 32b accesses. Fod bidirectional and misaligned inputs, copy the output data to an aligned buffer, do the transfer, then copy the read back data from temp aligned buffer to the real input buffer. * Fix comments, clean condition checks, save stack Add more comments and adjust naming to be more informative in transferBytes_ and *aligned_. Save 64bytes of stack in double misaligned case. * Optimize misaligned transfers, reduce code size On any misaligned input or output, always use a temp buffer. No need for special casing and bytewise ::transfer(). This should be faster as bytewise ::transfer involves a significant number of IO register accesses and setup. Thanks to @devyte for the suggestion.
91 lines
3.2 KiB
C++
91 lines
3.2 KiB
C++
/*
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SPI.h - SPI library for esp8266
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Copyright (c) 2015 Hristo Gochkov. All rights reserved.
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This file is part of the esp8266 core for Arduino environment.
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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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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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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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#ifndef _SPI_H_INCLUDED
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#define _SPI_H_INCLUDED
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#include <Arduino.h>
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#include <stdlib.h>
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#define SPI_HAS_TRANSACTION
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// This defines are not representing the real Divider of the ESP8266
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// the Defines match to an AVR Arduino on 16MHz for better compatibility
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#define SPI_CLOCK_DIV2 0x00101001 //8 MHz
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#define SPI_CLOCK_DIV4 0x00241001 //4 MHz
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#define SPI_CLOCK_DIV8 0x004c1001 //2 MHz
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#define SPI_CLOCK_DIV16 0x009c1001 //1 MHz
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#define SPI_CLOCK_DIV32 0x013c1001 //500 KHz
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#define SPI_CLOCK_DIV64 0x027c1001 //250 KHz
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#define SPI_CLOCK_DIV128 0x04fc1001 //125 KHz
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const uint8_t SPI_MODE0 = 0x00; ///< CPOL: 0 CPHA: 0
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const uint8_t SPI_MODE1 = 0x01; ///< CPOL: 0 CPHA: 1
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const uint8_t SPI_MODE2 = 0x10; ///< CPOL: 1 CPHA: 0
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const uint8_t SPI_MODE3 = 0x11; ///< CPOL: 1 CPHA: 1
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class SPISettings {
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public:
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SPISettings() :_clock(1000000), _bitOrder(LSBFIRST), _dataMode(SPI_MODE0){}
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SPISettings(uint32_t clock, uint8_t bitOrder, uint8_t dataMode) :_clock(clock), _bitOrder(bitOrder), _dataMode(dataMode){}
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uint32_t _clock;
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uint8_t _bitOrder;
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uint8_t _dataMode;
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};
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class SPIClass {
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public:
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SPIClass();
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bool pins(int8_t sck, int8_t miso, int8_t mosi, int8_t ss);
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void begin();
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void end();
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void setHwCs(bool use);
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void setBitOrder(uint8_t bitOrder);
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void setDataMode(uint8_t dataMode);
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void setFrequency(uint32_t freq);
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void setClockDivider(uint32_t clockDiv);
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void beginTransaction(SPISettings settings);
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uint8_t transfer(uint8_t data);
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uint16_t transfer16(uint16_t data);
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void transfer(void *buf, uint16_t count);
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void write(uint8_t data);
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void write16(uint16_t data);
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void write16(uint16_t data, bool msb);
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void write32(uint32_t data);
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void write32(uint32_t data, bool msb);
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void writeBytes(const uint8_t * data, uint32_t size);
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void writePattern(const uint8_t * data, uint8_t size, uint32_t repeat);
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void transferBytes(const uint8_t * out, uint8_t * in, uint32_t size);
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void endTransaction(void);
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private:
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bool useHwCs;
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uint8_t pinSet;
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void writeBytes_(const uint8_t * data, uint8_t size);
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void transferBytes_(const uint8_t * out, uint8_t * in, uint8_t size);
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void transferBytesAligned_(const uint8_t * out, uint8_t * in, uint8_t size);
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inline void setDataBits(uint16_t bits);
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};
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#if !defined(NO_GLOBAL_INSTANCES) && !defined(NO_GLOBAL_SPI)
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extern SPIClass SPI;
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#endif
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#endif
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