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libraries/SPI: abs -> std::abs and cast fixes #7362

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merged 6 commits into from
Jun 13, 2020
Merged

libraries/SPI: abs -> std::abs and cast fixes #7362

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436bbc6
libraries/SPI: remove pointless abs(...) call
mcspr Jun 8, 2020
cb8ed2a
additional changes for freq and constants
mcspr Jun 9, 2020
5f31800
Merge branch 'master' into lib-spi/man-abs
devyte Jun 9, 2020
a2b7aa0
Merge branch 'master' into lib-spi/man-abs
devyte Jun 10, 2020
6af0436
Merge branch 'master' into lib-spi/man-abs
earlephilhower Jun 12, 2020
ece351f
Merge branch 'master' into lib-spi/man-abs
earlephilhower Jun 13, 2020
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27 changes: 18 additions & 9 deletions libraries/SPI/SPI.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -203,6 +203,7 @@ void SPIClass::setFrequency(uint32_t freq) {
static uint32_t lastSetRegister = 0;

if(freq >= ESP8266_CLOCK) {
// magic number to set spi sysclock bit (see below.)
setClockDivider(0x80000000);
return;
}
Expand All @@ -215,7 +216,7 @@ void SPIClass::setFrequency(uint32_t freq) {
const spiClk_t minFreqReg = { 0x7FFFF020 };
uint32_t minFreq = ClkRegToFreq((spiClk_t*) &minFreqReg);
if(freq < minFreq) {
// use minimum possible clock
// use minimum possible clock regardless
setClockDivider(minFreqReg.regValue);
lastSetRegister = SPI1CLK;
lastSetFrequency = freq;
Expand All @@ -227,8 +228,14 @@ void SPIClass::setFrequency(uint32_t freq) {
spiClk_t bestReg = { 0 };
int32_t bestFreq = 0;

// find the best match
while(calN <= 0x3F) { // 0x3F max for N
// aka 0x3F, aka 63, max for regN:6
const uint8_t regNMax = (1 << 6) - 1;

// aka 0x1fff, aka 8191, max for regPre:13
const int32_t regPreMax = (1 << 13) - 1;

// find the best match for the next 63 iterations
while(calN <= regNMax) {

spiClk_t reg = { 0 };
int32_t calFreq;
Expand All @@ -239,8 +246,8 @@ void SPIClass::setFrequency(uint32_t freq) {

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
if(calPre > regPreMax) {
reg.regPre = regPreMax;
} else if(calPre <= 0) {
reg.regPre = 0;
} else {
Expand All @@ -254,19 +261,21 @@ void SPIClass::setFrequency(uint32_t freq) {
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) {
if(calFreq == static_cast<int32_t>(freq)) {
// accurate match use it!
memcpy(&bestReg, &reg, sizeof(bestReg));
break;
} else if(calFreq < (int32_t) freq) {
} else if(calFreq < static_cast<int32_t>(freq)) {
// never go over the requested frequency
if(abs(freq - calFreq) < abs(freq - bestFreq)) {
auto cal = std::abs(static_cast<int32_t>(freq) - calFreq);
auto best = std::abs(static_cast<int32_t>(freq) - bestFreq);
if(cal < best) {
bestFreq = calFreq;
memcpy(&bestReg, &reg, sizeof(bestReg));
}
}
}
if(calFreq == (int32_t) freq) {
if(calFreq == static_cast<int32_t>(freq)) {
// accurate match use it!
break;
}
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1 change: 0 additions & 1 deletion libraries/SPI/SPI.h
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Original file line number Diff line number Diff line change
Expand Up @@ -22,7 +22,6 @@
#define _SPI_H_INCLUDED

#include <Arduino.h>
#include <stdlib.h>

#define SPI_HAS_TRANSACTION 1

Expand Down