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DCCTimer_AVR - incorporate Haba's optimisations to ADC scanning

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This commit is contained in:
Neil McKechnie 2023-02-07 23:18:59 +00:00
parent 73a7d3e0ca
commit efb2666060
2 changed files with 51 additions and 56 deletions
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16
DCCTimer.h
View File

@ -1,5 +1,5 @@
/*
* © 2022-2023 Paul M. Antoine
* © 2022 Paul M. Antoine
* © 2021 Mike S
* © 2021-2022 Harald Barth
* © 2021 Fred Decker
@ -102,14 +102,9 @@ private:
// that an offset can be initialized.
class ADCee {
public:
// begin is called for any setup that must be done before
// **init** can be called. On some architectures this involves ADC
// initialisation and clock routing, sampling times etc.
static void begin();
// init adds the pin to the list of scanned pins (if this
// init does add the pin to the list of scanned pins (if this
// platform's implementation scans pins) and returns the first
// read value (which is why it required begin to have been called first!)
// It must be called before the regular scan is started.
// read value. It is called before the regular scan is started.
static int init(uint8_t pin);
// read does read the pin value from the scanned cache or directly
// if this is a platform that does not scan. fromISR is a hint if
@ -118,6 +113,9 @@ public:
static int read(uint8_t pin, bool fromISR=false);
// returns possible max value that the ADC can return
static int16_t ADCmax();
// begin is called for any setup that must be done before
// scan can be called.
static void begin();
private:
// On platforms that scan, it is called from waveform ISR
// only on a regular basis.
@ -126,6 +124,8 @@ private:
static uint16_t usedpins;
// cached analog values (malloc:ed to actual number of ADC channels)
static int *analogvals;
// ids to scan (new way)
static byte *idarr;
// friend so that we can call scan() and begin()
friend class DCCWaveform;
};

91
DCCTimerAVR.cpp
View File

@ -123,13 +123,14 @@ void DCCTimer::reset() {
}
#if defined(ARDUINO_AVR_MEGA) || defined(ARDUINO_AVR_MEGA2560)
#define NUM_ADC_INPUTS 15
#define NUM_ADC_INPUTS 16
#else
#define NUM_ADC_INPUTS 7
#define NUM_ADC_INPUTS 8
#endif
uint16_t ADCee::usedpins = 0;
int * ADCee::analogvals = NULL;
bool ADCusesHighPort = false;
byte *ADCee::idarr = NULL;
static bool ADCusesHighPort = false;
/*
* Register a new pin to be scanned
@ -138,16 +139,28 @@ bool ADCusesHighPort = false;
*/
int ADCee::init(uint8_t pin) {
uint8_t id = pin - A0;
if (id > NUM_ADC_INPUTS)
byte n;
if (id >= NUM_ADC_INPUTS)
return -1023;
if (id > 7)
ADCusesHighPort = true;
pinMode(pin, INPUT);
int value = analogRead(pin);
if (analogvals == NULL)
analogvals = (int *)calloc(NUM_ADC_INPUTS+1, sizeof(int));
analogvals[id] = value;
usedpins |= (1<<id);
if (analogvals == NULL) {
analogvals = (int *)calloc(NUM_ADC_INPUTS, sizeof(int));
for (n=0 ; n < NUM_ADC_INPUTS; n++) // set unreasonable value at startup as marker
analogvals[n] = -32768; // 16 bit int min value
idarr = (byte *)calloc(NUM_ADC_INPUTS+1, sizeof(byte)); // +1 for terminator value
for (n=0 ; n <= NUM_ADC_INPUTS; n++)
idarr[n] = 255; // set 255 as end of array marker
}
analogvals[id] = value; // store before enable by idarr[n]
for (n=0 ; n <= NUM_ADC_INPUTS; n++) {
if (idarr[n] == 255) {
idarr[n] = id;
break;
}
}
return value;
}
int16_t ADCee::ADCmax() {
@ -159,11 +172,13 @@ int16_t ADCee::ADCmax() {
int ADCee::read(uint8_t pin, bool fromISR) {
(void)fromISR; // AVR does ignore this arg
uint8_t id = pin - A0;
if ((usedpins & (1<<id) ) == 0)
return -1023;
int a;
// we do not need to check (analogvals == NULL)
// because usedpins would still be 0 in that case
return analogvals[id];
noInterrupts();
a = analogvals[id];
interrupts();
return a;
}
/*
* Scan function that is called from interrupt
@ -171,8 +186,7 @@ int ADCee::read(uint8_t pin, bool fromISR) {
#pragma GCC push_options
#pragma GCC optimize ("-O3")
void ADCee::scan() {
static byte id = 0; // id and mask are the same thing but it is faster to
static uint16_t mask = 1; // increment and shift instead to calculate mask from id
static byte num = 0; // index into id array
static bool waiting = false;
if (waiting) {
@ -184,45 +198,26 @@ void ADCee::scan() {
low = ADCL; //must read low before high
high = ADCH;
bitSet(ADCSRA, ADIF);
analogvals[id] = (high << 8) | low;
// advance at least one track
// for scope debug TrackManager::track[1]->setBrake(0);
analogvals[idarr[num]] = (high << 8) | low;
waiting = false;
id++;
mask = mask << 1;
if (id == NUM_ADC_INPUTS+1) {
id = 0;
mask = 1;
}
}
if (!waiting) {
if (usedpins == 0) // otherwise we would loop forever
return;
// look for a valid track to sample or until we are around
while (true) {
if (mask & usedpins) {
// start new ADC aquire on id
// cycle around in-use analogue pins
num++;
if (idarr[num] == 255)
num = 0;
// start new ADC aquire on id
#if defined(ADCSRB) && defined(MUX5)
if (ADCusesHighPort) { // if we ever have started to use high pins)
if (id > 7) // if we use a high ADC pin
bitSet(ADCSRB, MUX5); // set MUX5 bit
else
bitClear(ADCSRB, MUX5);
}
#endif
ADMUX=(1<<REFS0)|(id & 0x07); //select AVCC as reference and set MUX
bitSet(ADCSRA,ADSC); // start conversion
// for scope debug TrackManager::track[1]->setBrake(1);
waiting = true;
return;
}
id++;
mask = mask << 1;
if (id == NUM_ADC_INPUTS+1) {
id = 0;
mask = 1;
}
if (ADCusesHighPort) { // if we ever have started to use high pins)
if (idarr[num] > 7) // if we use a high ADC pin
bitSet(ADCSRB, MUX5); // set MUX5 bit
else
bitClear(ADCSRB, MUX5);
}
#endif
ADMUX = (1 << REFS0) | (idarr[num] & 0x07); // select AVCC as reference and set MUX
bitSet(ADCSRA, ADSC); // start conversion
waiting = true;
}
}
#pragma GCC pop_options
@ -236,4 +231,4 @@ void ADCee::begin() {
//bitSet(ADCSRA, ADSC); //do not start the ADC yet. Done when we have set the MUX
interrupts();
}
#endif
#endif