Chris Taylor / SignalCapture

Provides a simple way to capture the wave form of a pin. For example it can be used to capture the digital state transitions of a pin connected to an IR receiver. These signals can later be played back using the Signal Generator library to control IR devices. The library supports two means of capturing the signal. The signal can be captured on any digital pin using polling while for higher resolution and more accurate timing the interrupt driven capture feature can be used.

DigitalPinCapture.h@0:c6f86d422a7e, 2014-09-27 (annotated)

Committer:
taylorza
Date:
Sat Sep 27 04:04:16 2014 +0000
Revision:
0:c6f86d422a7e
Initial commit of the Signal Capture library

Who changed what in which revision?

UserRevisionLine numberNew contents of line
taylorza 0:c6f86d422a7e 1 ///////////////////////////////////////////////////////////////////////////////
taylorza 0:c6f86d422a7e 2 // Signal Capture Library
taylorza 0:c6f86d422a7e 3 // Author: Chris Taylor (taylorza)
taylorza 0:c6f86d422a7e 4 #ifndef __DIGITALPINCAPTURE_H__
taylorza 0:c6f86d422a7e 5 #define __DIGITALPINCAPTURE_H__
taylorza 0:c6f86d422a7e 6
taylorza 0:c6f86d422a7e 7 /** Captures the digital wave form of a pin into a timing buffer. */
taylorza 0:c6f86d422a7e 8 class DigitalPinCapture
taylorza 0:c6f86d422a7e 9 {
taylorza 0:c6f86d422a7e 10 public:
taylorza 0:c6f86d422a7e 11 /** Create an instance of DigitalPinCapture connected to the specified pin
taylorza 0:c6f86d422a7e 12 * @note The DigitalPinCapture class polls the state of the pin and therefore might be less accurate than
taylorza 0:c6f86d422a7e 13 * using InterruptPinCapture. However, it has the advantage that it does not require an interrupt capable pin.
taylorza 0:c6f86d422a7e 14 */
taylorza 0:c6f86d422a7e 15 DigitalPinCapture(PinName pin, PinMode mode);
taylorza 0:c6f86d422a7e 16
taylorza 0:c6f86d422a7e 17 /** Maximum time to wait for waveform data to arrive or completely fill the timing buffer.
taylorza 0:c6f86d422a7e 18 * @param us Timeout specified in microseconds
taylorza 0:c6f86d422a7e 19 */
taylorza 0:c6f86d422a7e 20 void setReadTimeout(uint32_t us);
taylorza 0:c6f86d422a7e 21
taylorza 0:c6f86d422a7e 22 /** Waits for the pin to transition to the trigger state and proceeds to capture the
taylorza 0:c6f86d422a7e 23 * pins transition timing into the timing buffer.
taylorza 0:c6f86d422a7e 24 * @param triggerState State that the pin must transistion to before the readings are captured
taylorza 0:c6f86d422a7e 25 * @param pReadings Pointer to the timing buffer that will contain the readings in microseconds
taylorza 0:c6f86d422a7e 26 * @param count The maximum number of readings that can be held in the buffer
taylorza 0:c6f86d422a7e 27 * @returns The number of timings captured in the buffer.
taylorza 0:c6f86d422a7e 28 */
taylorza 0:c6f86d422a7e 29 int read(bool triggerState, uint32_t *pReadings, int count);
taylorza 0:c6f86d422a7e 30
taylorza 0:c6f86d422a7e 31 /** Immediately start capturing the pin transition timing into the timing buffer.
taylorza 0:c6f86d422a7e 32 * @param pInitialState Pointer to a bool that will have the initial state of the pin at the time the capture started.
taylorza 0:c6f86d422a7e 33 * @param pReadings Pointer to the timing buffer that will contain the readings in microseconds
taylorza 0:c6f86d422a7e 34 * @param count The maximum number of readings that can be held in the buffer
taylorza 0:c6f86d422a7e 35 * @returns The number of timings captured in the buffer.
taylorza 0:c6f86d422a7e 36 */
taylorza 0:c6f86d422a7e 37 int read(bool *pInitialState, uint32_t *pReadings, int count);
taylorza 0:c6f86d422a7e 38
taylorza 0:c6f86d422a7e 39 private:
taylorza 0:c6f86d422a7e 40 int readInternal(bool *pPinState, uint32_t *pReadings, int count, bool waitForTrigger);
taylorza 0:c6f86d422a7e 41
taylorza 0:c6f86d422a7e 42 private:
taylorza 0:c6f86d422a7e 43 DigitalIn _signalPin;
taylorza 0:c6f86d422a7e 44 uint32_t _readTimeout;
taylorza 0:c6f86d422a7e 45 };
taylorza 0:c6f86d422a7e 46 #endif //__DIGITALPINCAPTURE_H__