I messed up the merge, so pushing it over to another repo so I don't lose it. Will tidy up and remove later
Dependencies: BufferedSerial FatFileSystemCpp mbed
LTCDecode.cpp@9:7214e3c3e5f8, 2021-02-18 (annotated)
- Committer:
- AndyA
- Date:
- Thu Feb 18 18:15:48 2021 +0000
- Revision:
- 9:7214e3c3e5f8
- Parent:
- 1:dd1f7e162f91
- Child:
- 10:053bac3e326b
massive ripup and redesign; currently has file system build errors
Who changed what in which revision?
User | Revision | Line number | New contents of line |
---|---|---|---|
AndyA | 0:97661408d0f9 | 1 | #include "LTCDecode.h" |
AndyA | 0:97661408d0f9 | 2 | |
AndyA | 9:7214e3c3e5f8 | 3 | |
AndyA | 9:7214e3c3e5f8 | 4 | const uint32_t minBitPeriodUS = |
AndyA | 9:7214e3c3e5f8 | 5 | (uint32_t)((1000000.0f / 2400) / 1.1f); // allow for 10% time error |
AndyA | 9:7214e3c3e5f8 | 6 | const uint32_t maxMidSymbolTimeUS = (uint32_t)( |
AndyA | 9:7214e3c3e5f8 | 7 | ((1000000.0f / (1920 * 2))) * 1.1f); // allow for 10% time error |
AndyA | 0:97661408d0f9 | 8 | |
AndyA | 0:97661408d0f9 | 9 | |
AndyA | 1:dd1f7e162f91 | 10 | LTCDecode::LTCDecode(const PinName pin) : _LTCIn(pin) |
AndyA | 1:dd1f7e162f91 | 11 | { |
AndyA | 1:dd1f7e162f91 | 12 | LTCsynced = false; |
AndyA | 9:7214e3c3e5f8 | 13 | inputTimer.reset(); |
AndyA | 9:7214e3c3e5f8 | 14 | inputTimer.start(); |
AndyA | 9:7214e3c3e5f8 | 15 | FrameCallback = NULL; |
AndyA | 0:97661408d0f9 | 16 | } |
AndyA | 0:97661408d0f9 | 17 | |
AndyA | 9:7214e3c3e5f8 | 18 | void LTCDecode::enable(bool enable) |
AndyA | 1:dd1f7e162f91 | 19 | { |
AndyA | 9:7214e3c3e5f8 | 20 | LTCsynced = false; |
AndyA | 9:7214e3c3e5f8 | 21 | if (enable) { |
AndyA | 9:7214e3c3e5f8 | 22 | inputTimer.start(); |
AndyA | 9:7214e3c3e5f8 | 23 | inputTimer.reset(); |
AndyA | 9:7214e3c3e5f8 | 24 | _LTCIn.fall(callback(this, <CDecode::LTCOnEdge)); |
AndyA | 9:7214e3c3e5f8 | 25 | _LTCIn.rise(callback(this, <CDecode::LTCOnEdge)); |
AndyA | 9:7214e3c3e5f8 | 26 | } else { |
AndyA | 9:7214e3c3e5f8 | 27 | inputTimer.stop(); |
AndyA | 9:7214e3c3e5f8 | 28 | _LTCIn.fall(NULL); |
AndyA | 9:7214e3c3e5f8 | 29 | _LTCIn.rise(NULL); |
AndyA | 9:7214e3c3e5f8 | 30 | } |
AndyA | 0:97661408d0f9 | 31 | } |
AndyA | 0:97661408d0f9 | 32 | |
AndyA | 1:dd1f7e162f91 | 33 | void LTCDecode::LTCOnEdge() |
AndyA | 1:dd1f7e162f91 | 34 | { |
AndyA | 9:7214e3c3e5f8 | 35 | uint32_t transitionTime = inputTimer.read_us(); |
AndyA | 1:dd1f7e162f91 | 36 | uint32_t period = (transitionTime - lastTransition); |
AndyA | 1:dd1f7e162f91 | 37 | lastTransition = transitionTime; |
AndyA | 9:7214e3c3e5f8 | 38 | bool gotSync = false; |
AndyA | 9:7214e3c3e5f8 | 39 | |
AndyA | 9:7214e3c3e5f8 | 40 | if (period > maxMidSymbolTimeUS) { // time since last transition is > maximum time for |
AndyA | 1:dd1f7e162f91 | 41 | // a 1, must be a zero and start of the next bit. |
AndyA | 1:dd1f7e162f91 | 42 | // printf("Z"); |
AndyA | 1:dd1f7e162f91 | 43 | lastBitStart = transitionTime; |
AndyA | 9:7214e3c3e5f8 | 44 | addBitToBuffer(false); // can't be an end of frame, they must end on a 1 |
AndyA | 1:dd1f7e162f91 | 45 | return; |
AndyA | 0:97661408d0f9 | 46 | } |
AndyA | 9:7214e3c3e5f8 | 47 | |
AndyA | 1:dd1f7e162f91 | 48 | // if it's not a 0 it must be a 1 but are we at the end of the bit yet? |
AndyA | 1:dd1f7e162f91 | 49 | if ((transitionTime - lastBitStart)> minBitPeriodUS) { // end of a bit |
AndyA | 1:dd1f7e162f91 | 50 | lastBitStart = transitionTime; |
AndyA | 9:7214e3c3e5f8 | 51 | gotSync = addBitToBuffer(false); // can't be an end of frame, they must end on a 1 |
AndyA | 9:7214e3c3e5f8 | 52 | if (gotSync) { |
AndyA | 9:7214e3c3e5f8 | 53 | LTCsynced = true; |
AndyA | 9:7214e3c3e5f8 | 54 | decodeTime(); |
AndyA | 9:7214e3c3e5f8 | 55 | if (FrameCallback) |
AndyA | 9:7214e3c3e5f8 | 56 | FrameCallback.call(); |
AndyA | 9:7214e3c3e5f8 | 57 | } |
AndyA | 1:dd1f7e162f91 | 58 | } |
AndyA | 0:97661408d0f9 | 59 | } |
AndyA | 0:97661408d0f9 | 60 | |
AndyA | 9:7214e3c3e5f8 | 61 | // add a bit. Return true if we got the end of frame pattern |
AndyA | 9:7214e3c3e5f8 | 62 | bool LTCDecode::addBitToBuffer(bool bit) |
AndyA | 1:dd1f7e162f91 | 63 | { |
AndyA | 9:7214e3c3e5f8 | 64 | LTCBuffer[0] = LTCBuffer[0]>> 1; |
AndyA | 9:7214e3c3e5f8 | 65 | if (LTCBuffer[1] &= 0x01) |
AndyA | 9:7214e3c3e5f8 | 66 | LTCBuffer[0] |= 0x80000000; |
AndyA | 9:7214e3c3e5f8 | 67 | |
AndyA | 9:7214e3c3e5f8 | 68 | LTCBuffer[1] = LTCBuffer[1]>> 1; |
AndyA | 9:7214e3c3e5f8 | 69 | if (LTCBuffer[2] &= 0x01) |
AndyA | 9:7214e3c3e5f8 | 70 | LTCBuffer[1] |= 0x80000000; |
AndyA | 9:7214e3c3e5f8 | 71 | |
AndyA | 9:7214e3c3e5f8 | 72 | LTCBuffer[2] = LTCBuffer[2]>> 1; |
AndyA | 9:7214e3c3e5f8 | 73 | if (bit) |
AndyA | 9:7214e3c3e5f8 | 74 | LTCBuffer[2]|= 0x80000000; |
AndyA | 9:7214e3c3e5f8 | 75 | |
AndyA | 9:7214e3c3e5f8 | 76 | // frame sync patterin is 1011 1111 1111 1100 |
AndyA | 9:7214e3c3e5f8 | 77 | // if it's a valid sync we will have it just received (buffer2 top bits) and the one from the last frame still in the buffer as the low 16 bits of buffer 0. |
AndyA | 9:7214e3c3e5f8 | 78 | return ((((LTCBuffer[2]>>16) & 0x0000FFFF) == 0xBFFC) && ((LTCBuffer[0] & 0x0000FFFF) == 0xBFFC)); |
AndyA | 1:dd1f7e162f91 | 79 | } |
AndyA | 0:97661408d0f9 | 80 | |
AndyA | 9:7214e3c3e5f8 | 81 | void LTCDecode::decodeTime() |
AndyA | 1:dd1f7e162f91 | 82 | { |
AndyA | 9:7214e3c3e5f8 | 83 | _frame = LTCBuffer[0]>>16 & 0x0f + ((LTCBuffer[0] >> 24) & 0x03) * 10; |
AndyA | 9:7214e3c3e5f8 | 84 | _seconds = LTCBuffer[1]>>0 & 0x0f + ((LTCBuffer[1] >> 8) & 0x07) * 10; |
AndyA | 9:7214e3c3e5f8 | 85 | _minutes = LTCBuffer[1]>>16 & 0x0f + ((LTCBuffer[1] >> 24) & 0x07) * 10; |
AndyA | 9:7214e3c3e5f8 | 86 | _hours = LTCBuffer[2]>>0 & 0x0f + ((LTCBuffer[2] >> 8) & 0x03) * 10; |
AndyA | 9:7214e3c3e5f8 | 87 | _frameDrop = (LTCBuffer[0] & (1<<26)); |
AndyA | 0:97661408d0f9 | 88 | } |