Buffer output after adding some initial silence.

FMRB.h

@@ -0,0 +1,72 @@
+/*
+Serial fifo control - Copyright (C) KI6ZUM 2015
+Copyright (C) 2015,2016,2020 by Jonathan Naylor G4KLX
+
+This library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Library General Public
+License as published by the Free Software Foundation; either
+version 2 of the License, or (at your option) any later version.
+
+This library is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+Library General Public License for more details.
+
+You should have received a copy of the GNU Library General Public
+License along with this library; if not, write to the
+Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
+Boston, MA  02110-1301, USA.
+*/
+
+#if !defined(FMRB_H)
+#define  FMRB_H
+
+#if defined(STM32F4XX)
+#include "stm32f4xx.h"
+#elif defined(STM32F7XX)
+#include "stm32f7xx.h"
+#elif defined(STM32F105xC)
+#include "stm32f1xx.h"
+#include <cstddef>
+#else
+#include <Arduino.h>
+#endif
+
+#if defined(__SAM3X8E__) || defined(STM32F105xC)
+#define  ARM_MATH_CM3
+#elif defined(STM32F7XX)
+#define  ARM_MATH_CM7
+#elif defined(STM32F4XX) || defined(__MK20DX256__) || defined(__MK64FX512__) || defined(__MK66FX1M0__)
+#define  ARM_MATH_CM4
+#else
+#error "Unknown processor type"
+#endif
+
+#include <arm_math.h>
+
+class CFMRB {
+public:
+  CFMRB(uint16_t length);
+  
+  uint16_t getSpace() const;
+  
+  uint16_t getData() const;
+
+  bool put(q15_t sample);
+
+  bool get(q15_t& sample);
+
+  bool hasOverflowed();
+
+  void reset();
+
+private:
+  uint16_t          m_length;
+  volatile q15_t*   m_samples;
+  volatile uint16_t m_head;
+  volatile uint16_t m_tail;
+  volatile bool     m_full;
+  bool              m_overflow;
+};
+
+#endif