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esp8266/libraries/SPI/SPI.cpp
John Doe 6ab3c76e03 register and clock changes
2015-06-02 00:11:20 +03:00

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/*
SPI.cpp - SPI library for esp8266
Copyright (c) 2015 Hristo Gochkov. All rights reserved.
This file is part of the esp8266 core for Arduino environment.
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "SPI.h"
#include "HardwareSerial.h"
typedef union {
uint32_t regValue;
struct {
unsigned regL :6;
unsigned regH :6;
unsigned regN :6;
unsigned regPre :13;
unsigned regEQU :1;
};
} spiClk_t;
SPIClass SPI;
SPIClass::SPIClass() {
useHwCs = false;
}
void SPIClass::begin() {
pinMode(SCK, SPECIAL); ///< GPIO14
pinMode(MISO, SPECIAL); ///< GPIO12
pinMode(MOSI, SPECIAL); ///< GPIO13
SPI1C = 0;
setFrequency(1000000); ///< 1MHz
SPI1U = SPIUMOSI | SPIUDUPLEX | SPIUSSE;
SPI1U1 = (7 << SPILMOSI) | (7 << SPILMISO);
SPI1C1 = 0;
}
void SPIClass::end() {
pinMode(SCK, INPUT);
pinMode(MISO, INPUT);
pinMode(MOSI, INPUT);
if(useHwCs) {
pinMode(SS, INPUT);
}
}
void SPIClass::setHwCs(bool use) {
if(use) {
pinMode(SS, SPECIAL); ///< GPIO15
SPI1U |= (SPIUCSSETUP | SPIUCSHOLD);
} else {
if(useHwCs) {
pinMode(SS, INPUT);
SPI1U &= ~(SPIUCSSETUP | SPIUCSHOLD);
}
}
useHwCs = use;
}
void SPIClass::beginTransaction(SPISettings settings) {
while(SPI1CMD & SPIBUSY) {}
setFrequency(settings._clock);
setBitOrder(settings._bitOrder);
setDataMode(settings._dataMode);
}
void SPIClass::endTransaction() {
}
void SPIClass::setDataMode(uint8_t dataMode) {
/**
SPI_MODE0 0x00 - CPOL: 0 CPHA: 0
SPI_MODE1 0x01 - CPOL: 0 CPHA: 1
SPI_MODE2 0x10 - CPOL: 1 CPHA: 0
SPI_MODE3 0x11 - CPOL: 1 CPHA: 1
*/
bool CPOL = (dataMode & 0x10); ///< CPOL (Clock Polarity)
bool CPHA = (dataMode & 0x01); ///< CPHA (Clock Phase)
if(CPHA) {
SPI1U |= (SPIUSME);
} else {
SPI1U &= ~(SPIUSME);
}
if(CPOL) {
//todo How set CPOL???
}
}
void SPIClass::setBitOrder(uint8_t bitOrder) {
if(bitOrder == MSBFIRST) {
SPI1C &= ~(SPICWBO | SPICRBO);
} else {
SPI1C |= (SPICWBO | SPICRBO);
}
}
/**
* calculate the Frequency based on the register value
* @param reg
* @return
*/
static uint32_t ClkRegToFreq(spiClk_t * reg) {
return (ESP8266_CLOCK / ((reg->regPre + 1) * (reg->regN + 1)));
}
void SPIClass::setFrequency(uint32_t freq) {
static uint32_t lastSetFrequency = 0;
static uint32_t lastSetRegister = 0;
if(freq >= ESP8266_CLOCK) {
setClockDivider(0x80000000);
return;
}
if(lastSetFrequency == freq && lastSetRegister == SPI1CLK) {
// do nothing (speed optimization)
return;
}
const spiClk_t minFreqReg = { 0x7FFFF000 };
uint32_t minFreq = ClkRegToFreq((spiClk_t*) &minFreqReg);
if(freq < minFreq) {
// use minimum possible clock
setClockDivider(minFreqReg.regValue);
lastSetRegister = SPI1CLK;
lastSetFrequency = freq;
return;
}
uint8_t calN = 1;
spiClk_t bestReg = { 0 };
int32_t bestFreq = 0;
// find the best match
while(calN <= 0x3F) { // 0x3F max for N
spiClk_t reg = { 0 };
int32_t calFreq;
int32_t calPre;
int8_t calPreVari = -2;
reg.regN = calN;
while(calPreVari++ <= 1) { // test different variants for Pre (we calculate in int so we miss the decimals, testing is the easyest and fastest way)
calPre = (((ESP8266_CLOCK / (reg.regN + 1)) / freq) - 1) + calPreVari;
if(calPre > 0x1FFF) {
reg.regPre = 0x1FFF; // 8191
} else if(calPre <= 0) {
reg.regPre = 0;
} else {
reg.regPre = calPre;
}
reg.regL = ((reg.regN + 1) / 2);
// reg.regH = (reg.regN - reg.regL);
// test calculation
calFreq = ClkRegToFreq(&reg);
//os_printf("-----[0x%08X][%d]\t EQU: %d\t Pre: %d\t N: %d\t H: %d\t L: %d = %d\n", reg.regValue, freq, reg.regEQU, reg.regPre, reg.regN, reg.regH, reg.regL, calFreq);
if(calFreq == (int32_t) freq) {
// accurate match use it!
memcpy(&bestReg, &reg, sizeof(bestReg));
break;
} else if(calFreq < (int32_t) freq) {
// never go over the requested frequency
if(abs(freq - calFreq) < abs(freq - bestFreq)) {
bestFreq = calFreq;
memcpy(&bestReg, &reg, sizeof(bestReg));
}
}
}
if(calFreq == (int32_t) freq) {
// accurate match use it!
break;
}
calN++;
}
// os_printf("[0x%08X][%d]\t EQU: %d\t Pre: %d\t N: %d\t H: %d\t L: %d\t - Real Frequency: %d\n", bestReg.regValue, freq, bestReg.regEQU, bestReg.regPre, bestReg.regN, bestReg.regH, bestReg.regL, ClkRegToFreq(&bestReg));
setClockDivider(bestReg.regValue);
lastSetRegister = SPI1CLK;
lastSetFrequency = freq;
}
void SPIClass::setClockDivider(uint32_t clockDiv) {
if(clockDiv == 0x80000000) {
GPMUX |= (1 << 9); // Set bit 9 if sysclock required
} else {
GPMUX &= ~(1 << 9);
}
SPI1CLK = clockDiv;
}
inline void SPIClass::setDataBits(uint16_t bits) {
const uint32_t mask = ~((SPIMMOSI << SPILMOSI) | (SPIMMISO << SPILMISO));
bits--;
SPI1U1 = ((SPI1U1 & mask) | ((bits << SPILMOSI) | (bits << SPILMISO)));
}
uint8_t SPIClass::transfer(uint8_t data) {
while(SPI1CMD & SPIBUSY) {}
// reset to 8Bit mode
setDataBits(8);
SPI1W0 = data;
SPI1CMD |= SPIBUSY;
while(SPI1CMD & SPIBUSY) {}
return (uint8_t) (SPI1W0 & 0xff);
}
uint16_t SPIClass::transfer16(uint16_t data) {
union {
uint16_t val;
struct {
uint8_t lsb;
uint8_t msb;
};
} in, out;
in.val = data;
if((SPI1C & (SPICWBO | SPICRBO))) {
//MSBFIRST
out.msb = transfer(in.msb);
out.lsb = transfer(in.lsb);
} else {
//LSBFIRST
out.lsb = transfer(in.lsb);
out.msb = transfer(in.msb);
}
return out.val;
}
void SPIClass::write(uint8_t data) {
while(SPI1CMD & SPIBUSY) {}
// reset to 8Bit mode
setDataBits(8);
SPI1W0 = data;
SPI1CMD |= SPIBUSY;
while(SPI1CMD & SPIBUSY) {}
}
void SPIClass::write16(uint16_t data) {
write16(data, !(SPI1C & (SPICWBO | SPICRBO)));
}
void SPIClass::write16(uint16_t data, bool msb) {
while(SPI1CMD & SPIBUSY) {}
// Set to 16Bits transfer
setDataBits(16);
if(msb) {
// MSBFIRST Byte first
SPI1W0 = (data >> 8) | (data << 8);
SPI1CMD |= SPIBUSY;
} else {
// LSBFIRST Byte first
SPI1W0 = data;
SPI1CMD |= SPIBUSY;
}
while(SPI1CMD & SPIBUSY) {}
}
void SPIClass::write32(uint32_t data) {
write32(data, !(SPI1C & (SPICWBO | SPICRBO)));
}
void SPIClass::write32(uint32_t data, bool msb) {
while(SPI1CMD & SPIBUSY) {}
// Set to 32Bits transfer
setDataBits(32);
if(msb) {
union {
uint32_t l;
uint8_t b[4];
} data_;
data_.l = data;
// MSBFIRST Byte first
SPI1W0 = (data_.b[3] | (data_.b[2] << 8) | (data_.b[1] << 16) | (data_.b[0] << 24));
SPI1CMD |= SPIBUSY;
} else {
// LSBFIRST Byte first
SPI1W0 = data;
SPI1CMD |= SPIBUSY;
}
while(SPI1CMD & SPIBUSY) {}
}
/**
* Note:
* data need to be aligned to 32Bit
* or you get an Fatal exception (9)
* @param data uint8_t *
* @param size uint32_t
*/
void SPIClass::writeBytes(uint8_t * data, uint32_t size) {
while(size) {
if(size > 64) {
writeBytes_(data, 64);
size -= 64;
data += 64;
} else {
writeBytes_(data, size);
size = 0;
}
}
}
void SPIClass::writeBytes_(uint8_t * data, uint8_t size) {
while(SPI1CMD & SPIBUSY) {}
// Set Bits to transfer
setDataBits(size * 8);
volatile uint32_t * fifoPtr = &SPI1W0;
uint32_t * dataPtr = (uint32_t*) data;
uint8_t dataSize = ((size + 3) / 4);
while(dataSize--) {
*fifoPtr = *dataPtr;
dataPtr++;
fifoPtr++;
}
SPI1CMD |= SPIBUSY;
while(SPI1CMD & SPIBUSY) {}
}
/**
* Note:
* data need to be aligned to 32Bit
* or you get an Fatal exception (9)
* @param data uint8_t *
* @param size uint8_t max for size is 64Byte
* @param repeat uint32_t
*/
void SPIClass::writePattern(uint8_t * data, uint8_t size, uint32_t repeat) {
if(size > 64) return; //max Hardware FIFO
uint32_t byte = (size * repeat);
uint8_t r = (64 / size);
while(byte) {
if(byte > 64) {
writePattern_(data, size, r);
byte -= 64;
} else {
writePattern_(data, size, (byte / size));
byte = 0;
}
}
}
void SPIClass::writePattern_(uint8_t * data, uint8_t size, uint8_t repeat) {
uint8_t bytes = (size * repeat);
uint8_t buffer[64];
uint8_t * bufferPtr = &buffer[0];
uint8_t * dataPtr;
uint8_t dataSize = bytes;
for(uint8_t i = 0; i < repeat; i++) {
dataSize = size;
dataPtr = data;
while(dataSize--) {
*bufferPtr = *dataPtr;
dataPtr++;
bufferPtr++;
}
}
writeBytes(&buffer[0], bytes);
}
/**
* Note:
* in and out need to be aligned to 32Bit
* or you get an Fatal exception (9)
* @param out uint8_t *
* @param in uint8_t *
* @param size uint32_t
*/
void SPIClass::transferBytes(uint8_t * out, uint8_t * in, uint32_t size) {
while(size) {
if(size > 64) {
transferBytes_(out, in, 64);
size -= 64;
if(out) out += 64;
if(in) in += 64;
} else {
transferBytes_(out, in, size);
size = 0;
}
}
}
void SPIClass::transferBytes_(uint8_t * out, uint8_t * in, uint8_t size) {
while(SPI1CMD & SPIBUSY) {}
// Set in/out Bits to transfer
setDataBits(size * 8);
volatile uint32_t * fifoPtr = &SPI1W0;
uint8_t dataSize = ((size + 3) / 4);
if(out) {
uint32_t * dataPtr = (uint32_t*) out;
while(dataSize--) {
*fifoPtr = *dataPtr;
dataPtr++;
fifoPtr++;
}
} else {
// no out data only read fill with dummy data!
while(dataSize--) {
*fifoPtr = 0xFFFFFFFF;
fifoPtr++;
}
}
SPI1CMD |= SPIBUSY;
while(SPI1CMD & SPIBUSY) {}
if(in) {
volatile uint8_t * fifoPtr8 = (volatile uint8_t *) &SPI1W0;
dataSize = size;
while(dataSize--) {
*in = *fifoPtr8;
in++;
fifoPtr8++;
}
}
}
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