mirror of
https://github.com/thunderbug1/Spherebot-Host-GUI.git
synced 2026-02-20 11:21:19 +01:00
128 lines
3.1 KiB
C++
128 lines
3.1 KiB
C++
#include "SoftwareServo.h"
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SoftwareServo *SoftwareServo::first;
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#define NO_ANGLE (0xff)
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SoftwareServo::SoftwareServo() : pin(0), angle(NO_ANGLE), pulse0(0), min16(34), max16(150), next(0)
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{}
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void SoftwareServo::setMinimumPulse(uint16_t t)
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{
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min16 = t/16;
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}
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void SoftwareServo::setMaximumPulse(uint16_t t)
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{
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max16 = t/16;
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}
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uint8_t SoftwareServo::attach(int pinArg)
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{
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pin = pinArg;
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angle = NO_ANGLE;
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pulse0 = 0;
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next = first;
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first = this;
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digitalWrite(pin, 0);
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pinMode(pin, OUTPUT);
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return 1;
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}
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void SoftwareServo::detach()
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{
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for (SoftwareServo **p=&first; *p!=0; p=&((*p)->next) ) {
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if (*p == this) {
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*p = this->next;
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this->next = 0;
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return;
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}
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}
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}
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void SoftwareServo::write(int angleArg)
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{
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if (angleArg < 0) angleArg = 0;
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if (angleArg > 180) angleArg = 180;
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angle = angleArg;
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// bleh, have to use longs to prevent overflow, could be tricky if always a 16MHz clock, but not true
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// That 64L on the end is the TCNT0 prescaler, it will need to change if the clock's prescaler changes,
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// but then there will likely be an overflow problem, so it will have to be handled by a human.
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pulse0 = (min16*16L*clockCyclesPerMicrosecond() + (max16-min16)*(16L*clockCyclesPerMicrosecond())*angle/180L)/64L;
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}
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uint8_t SoftwareServo::read()
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{
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return angle;
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}
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uint8_t SoftwareServo::attached()
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{
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for (SoftwareServo *p=first; p!=0; p=p->next ) {
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if (p == this) return 1;
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}
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return 0;
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}
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void SoftwareServo::refresh()
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{
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uint8_t count = 0, i = 0;
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uint16_t base = 0;
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SoftwareServo *p;
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static unsigned long lastRefresh = 0;
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unsigned long m = millis();
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// if we haven't wrapped millis, and 20ms have not passed, then don't do anything
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if (m >= lastRefresh && m < lastRefresh + 20) return;
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lastRefresh = m;
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for (p=first; p!=0; p=p->next ) if (p->pulse0) count++;
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if (count == 0) return;
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// gather all the SoftwareServos in an array
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SoftwareServo *s[count];
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for (p=first; p !=0; p=p->next ) if (p->pulse0) s[i++] = p;
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// bubblesort the SoftwareServos by pulse time, ascending order
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for(;;) {
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uint8_t moved = 0;
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for (i = 1; i < count; i++) {
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if (s[i]->pulse0 < s[i-1]->pulse0) {
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SoftwareServo *t = s[i];
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s[i] = s[i-1];
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s[i-1] = t;
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moved = 1;
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}
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}
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if (!moved) break;
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}
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// turn on all the pins
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// Note the timing error here... when you have many SoftwareServos going, the
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// ones at the front will get a pulse that is a few microseconds too long.
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// Figure about 4uS/SoftwareServo after them. This could be compensated, but I feel
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// it is within the margin of error of software SoftwareServos that could catch
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// an extra interrupt handler at any time.
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for (i=0; i<count; i++) digitalWrite(s[i]->pin, 1);
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uint8_t start = TCNT0;
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uint8_t now = start;
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uint8_t last = now;
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// Now wait for each pin's time in turn..
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for (i=0; i<count; i++) {
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uint16_t go = start + s[i]->pulse0;
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// loop until we reach or pass 'go' time
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for (;;) {
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now = TCNT0;
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if (now < last) base += 256;
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last = now;
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if (base+now > go) {
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digitalWrite(s[i]->pin, 0);
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break;
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}
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}
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}
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}
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