iforce2d Chris / Mbed 2 deprecated ubxDistanceMeter

Displays distance to start location on OLED screen.

Dependencies:   mbed

Clock.cpp@0:972874f31c98, 2018-03-07 (annotated)

Committer:
iforce2d
Date:
Wed Mar 07 12:49:14 2018 +0000
Revision:
0:972874f31c98
First commit

Who changed what in which revision?

UserRevisionLine numberNew contents of line
iforce2d 0:972874f31c98 1 #include <mbed.h>
iforce2d 0:972874f31c98 2
iforce2d 0:972874f31c98 3 // The us ticker is a wrapping uint32_t. We insert interrupts at
iforce2d 0:972874f31c98 4 // 0, 0x40000000, 0x8000000, and 0xC0000000, rather than just 0 or just 0xFFFFFFFF because there is
iforce2d 0:972874f31c98 5 // code that calls interrupts that are "very soon" immediately and we don't
iforce2d 0:972874f31c98 6 // want that. Also because if we only use 0 and 0x80000000 then there is a chance it would
iforce2d 0:972874f31c98 7 // be considered to be in the past and executed immediately.
iforce2d 0:972874f31c98 8
iforce2d 0:972874f31c98 9 class ExtendedClock : public TimerEvent
iforce2d 0:972874f31c98 10 {
iforce2d 0:972874f31c98 11 public:
iforce2d 0:972874f31c98 12 ExtendedClock()
iforce2d 0:972874f31c98 13 {
iforce2d 0:972874f31c98 14 // This also starts the us ticker.
iforce2d 0:972874f31c98 15 mTriggers = 0;
iforce2d 0:972874f31c98 16 insert(0x40000000);
iforce2d 0:972874f31c98 17 }
iforce2d 0:972874f31c98 18
iforce2d 0:972874f31c98 19 float read()
iforce2d 0:972874f31c98 20 {
iforce2d 0:972874f31c98 21 return read_us() / 1000000.0f;
iforce2d 0:972874f31c98 22 }
iforce2d 0:972874f31c98 23
iforce2d 0:972874f31c98 24 uint64_t read_ms()
iforce2d 0:972874f31c98 25 {
iforce2d 0:972874f31c98 26 return read_us() / 1000;
iforce2d 0:972874f31c98 27 }
iforce2d 0:972874f31c98 28
iforce2d 0:972874f31c98 29 uint64_t read_us()
iforce2d 0:972874f31c98 30 {
iforce2d 0:972874f31c98 31 return mTriggers * 0x40000000ull + (ticker_read(_ticker_data) & 0x3FFFFFFF);
iforce2d 0:972874f31c98 32 }
iforce2d 0:972874f31c98 33
iforce2d 0:972874f31c98 34 private:
iforce2d 0:972874f31c98 35 void handler()
iforce2d 0:972874f31c98 36 {
iforce2d 0:972874f31c98 37 ++mTriggers;
iforce2d 0:972874f31c98 38 // If this is the first time we've been called (at 0x4...)
iforce2d 0:972874f31c98 39 // then mTriggers now equals 1 and we want to insert at 0x80000000.
iforce2d 0:972874f31c98 40 insert((mTriggers+1) * 0x40000000);
iforce2d 0:972874f31c98 41 }
iforce2d 0:972874f31c98 42
iforce2d 0:972874f31c98 43 // The number of times the us_ticker has rolled over.
iforce2d 0:972874f31c98 44 uint32_t mTriggers;
iforce2d 0:972874f31c98 45 };
iforce2d 0:972874f31c98 46
iforce2d 0:972874f31c98 47 static ExtendedClock _GlobalClock;
iforce2d 0:972874f31c98 48
iforce2d 0:972874f31c98 49 // Return the number of seconds since boot.
iforce2d 0:972874f31c98 50 float clock_s()
iforce2d 0:972874f31c98 51 {
iforce2d 0:972874f31c98 52 return _GlobalClock.read();
iforce2d 0:972874f31c98 53 }
iforce2d 0:972874f31c98 54
iforce2d 0:972874f31c98 55 // Return the number of milliseconds since boot.
iforce2d 0:972874f31c98 56 uint64_t clock_ms()
iforce2d 0:972874f31c98 57 {
iforce2d 0:972874f31c98 58 return _GlobalClock.read_ms();
iforce2d 0:972874f31c98 59 }
iforce2d 0:972874f31c98 60
iforce2d 0:972874f31c98 61 // Return the number of microseconds since boot.
iforce2d 0:972874f31c98 62 uint64_t clock_us()
iforce2d 0:972874f31c98 63 {
iforce2d 0:972874f31c98 64 return _GlobalClock.read_us();
iforce2d 0:972874f31c98 65 }