Arnaud VALLEY / Mbed 2 deprecated Pinscape_Controller_V2_arnoz

Mirror with some correction

Dependencies:   mbed FastIO FastPWM USBDevice

IRRemote/IRRemote.h@116:7a67265d7c19, 2021-10-01 (annotated)

Committer:
arnoz
Date:
Fri Oct 01 08:19:46 2021 +0000
Revision:
116:7a67265d7c19
Parent:
77:0b96f6867312 
- Correct information regarding your last merge

Who changed what in which revision?

UserRevisionLine numberNew contents of line
mjr 77:0b96f6867312 1 // IR Remote Control send/receive library - common definitions
mjr 77:0b96f6867312 2
mjr 77:0b96f6867312 3 #ifndef _IRREMOTE_H_
mjr 77:0b96f6867312 4 #define _IRREMOTE_H_
mjr 77:0b96f6867312 5
mjr 77:0b96f6867312 6 namespace IRRemote
mjr 77:0b96f6867312 7 {
mjr 77:0b96f6867312 8
mjr 77:0b96f6867312 9 // Tolerance range for timing inaccuracies, as a percentage +/- of the
mjr 77:0b96f6867312 10 // reference time from the protocol specification. Our measured signal
mjr 77:0b96f6867312 11 // times will never exactly match the specification times, because
mjr 77:0b96f6867312 12 // neither the receiver nor the transmitter have perfect clocks. And
mjr 77:0b96f6867312 13 // even if we had a perfect clock, we'd still be a little off due to
mjr 77:0b96f6867312 14 // latencies in the detector hardware, the detector's signal processing
mjr 77:0b96f6867312 15 // (demodulation, filtering), and our own latencies in detecting and
mjr 77:0b96f6867312 16 // responding to signals on the input pin. So we need to add a little
mjr 77:0b96f6867312 17 // wiggle room in interpreting times: if the spec says we should see an
mjr 77:0b96f6867312 18 // X-microsecond IR-ON state (a "mark"), we can expect it to actually
mjr 77:0b96f6867312 19 // range from X-error to X+error. This tolerance value sets the error
mjr 77:0b96f6867312 20 // range we'll accept.
mjr 77:0b96f6867312 21 //
mjr 77:0b96f6867312 22 // Typical Arduino IR receiver implementations use 30% tolerances. I
mjr 77:0b96f6867312 23 // think we could be quite a bit tighter than that if we wanted to be,
mjr 77:0b96f6867312 24 // since the biggest source of timing inaccuracies on the Arduino systems
mjr 77:0b96f6867312 25 // is probably the Arduino itself - the CPU is fairly slow to start with,
mjr 77:0b96f6867312 26 // and most of the Arduino code I've seen uses polling to detect signal
mjr 77:0b96f6867312 27 // edges, which is inherently high-latency. We're on a relatively fast
mjr 77:0b96f6867312 28 // CPU, and we use interrupts to detect edges. In my own measurements
mjr 77:0b96f6867312 29 // of miscellaneous remotes, our readings seem to be within about 3% of
mjr 77:0b96f6867312 30 // spec, so I think 30% is far looser than we really need to be.
mjr 77:0b96f6867312 31 //
mjr 77:0b96f6867312 32 // The main reason to prefer tighter tolerances is that we want to
mjr 77:0b96f6867312 33 // work with many different transmitters from different vendors, using
mjr 77:0b96f6867312 34 // different protocols. Higher tolerances mean more ambiguity in
mjr 77:0b96f6867312 35 // identifying timing signatures. The tradeoff, of course, is that a
mjr 77:0b96f6867312 36 // lower tolerance means more chance of rejecting borderline signals
mjr 77:0b96f6867312 37 // that we could have interpreted properly. This will probably have
mjr 77:0b96f6867312 38 // to be fine-tuned over time based on practical experience. For now,
mjr 77:0b96f6867312 39 // it appears that the super loose Arduino levels work just fine, in
mjr 77:0b96f6867312 40 // that we can still easily identify protocols.
mjr 77:0b96f6867312 41 //const float tolerance = 0.3f;
mjr 77:0b96f6867312 42 const int toleranceShl8 = 77; // tolerance*256
mjr 77:0b96f6867312 43
mjr 77:0b96f6867312 44 // Check a reading against a reference value using a specified
mjr 77:0b96f6867312 45 // base value for figuring the tolerance. This is useful when
mjr 77:0b96f6867312 46 // looking for multiples of a base value, because it pegs the
mjr 77:0b96f6867312 47 // tolerance window to the base value rather than allowing it
mjr 77:0b96f6867312 48 // to grow at each multiple.
mjr 77:0b96f6867312 49 inline bool inRange(int reading, int referenceVal, int baseVal)
mjr 77:0b96f6867312 50 {
mjr 77:0b96f6867312 51 int delta = (baseVal * toleranceShl8) >> 8;
mjr 77:0b96f6867312 52 return reading > referenceVal - delta && reading < referenceVal + delta;
mjr 77:0b96f6867312 53 }
mjr 77:0b96f6867312 54
mjr 77:0b96f6867312 55 // Check a reading against a reference value, applying the tolerance
mjr 77:0b96f6867312 56 // range to the reference value.
mjr 77:0b96f6867312 57 inline bool inRange(int reading, int referenceVal)
mjr 77:0b96f6867312 58 {
mjr 77:0b96f6867312 59 return inRange(reading, referenceVal, referenceVal);
mjr 77:0b96f6867312 60 }
mjr 77:0b96f6867312 61
mjr 77:0b96f6867312 62 // Test a reading against a reference value to see if it's out of
mjr 77:0b96f6867312 63 // range of the reference value above. This is equivalent to asking
mjr 77:0b96f6867312 64 // if the value is NOT inRange() AND is higher than the reference
mjr 77:0b96f6867312 65 // value.
mjr 77:0b96f6867312 66 inline bool aboveRange(uint32_t val, uint32_t ref, uint32_t baseVal)
mjr 77:0b96f6867312 67 {
mjr 77:0b96f6867312 68 return val > ref + ((baseVal*(256-toleranceShl8)) >> 8);
mjr 77:0b96f6867312 69 }
mjr 77:0b96f6867312 70
mjr 77:0b96f6867312 71 // Test a reading against a reference value to see if it's in range
mjr 77:0b96f6867312 72 // or above the range
mjr 77:0b96f6867312 73 inline bool inRangeOrAbove(uint32_t val, uint32_t ref, uint32_t baseVal)
mjr 77:0b96f6867312 74 {
mjr 77:0b96f6867312 75 int delta = (baseVal * toleranceShl8) >> 8;
mjr 77:0b96f6867312 76 return val > ref - delta;
mjr 77:0b96f6867312 77 }
mjr 77:0b96f6867312 78 }
mjr 77:0b96f6867312 79
mjr 77:0b96f6867312 80 #endif