added pulse_reader for DMA based NFC signal reading

updated nfcv to use pulse_reader instead of bitbanging
2026-07-16 00:18:11 -07:00 · 2022-11-19 00:38:42 +01:00
parent 24f8db3c27
commit 01137a5b6e
8 changed files with 432 additions and 264 deletions
@@ -0,0 +1,127 @@
+#pragma once
+
+#include <stdint.h>
+#include <stdlib.h>
+#include <stdbool.h>
+
+#include <furi_hal_gpio.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define PULSE_READER_NO_EDGE 0xFFFFFFFFUL
+#define F_CPU                64000000UL
+
+/**
+ * unit of the edge durations to return
+ */
+typedef enum {
+    PulseReaderUnit64MHz = 1,
+    PulseReaderUnitPicosecond = 15625
+} PulseReaderUnit;
+
+
+typedef struct {
+    bool start_level;
+    uint32_t* timer_buffer;
+    uint32_t size;
+    uint32_t pos;
+    uint32_t timer_value;
+    PulseReaderUnit unit;
+    uint32_t bit_time;
+    uint32_t dma_channel;
+    const GpioPin* gpio;
+} PulseReader;
+
+
+/** Allocate a PulseReader object
+ * 
+ * Allocates memory for a ringbuffer and initalizes the object
+ *
+ * @param[in]  gpio        the GPIO to use. will get configured as input.
+ * @param[in]  size        number of edges to buffer
+ */
+PulseReader* pulse_reader_alloc(const GpioPin* gpio, uint32_t size);
+
+
+/** Free a PulseReader object
+ * 
+ * Frees all memory of the given object
+ *
+ * @param[in]  signal      previously allocated PulseReader object.
+ */
+void pulse_reader_free(PulseReader* signal);
+
+
+/** Start signal capturing
+ * 
+ * Initializes DMA1, TIM2 and DMAMUX_REQ_GEN_0 to automatically capture timer values
+ *
+ * @param[in]  signal      previously allocated PulseReader object.
+ */
+void pulse_reader_start(PulseReader* signal);
+
+/** Stop signal capturing
+ * 
+ * Frees DMA1, TIM2 and DMAMUX_REQ_GEN_0
+ *
+ * @param[in]  signal      previously allocated PulseReader object.
+ */
+void pulse_reader_stop(PulseReader* signal);
+
+
+/** Recevie a sample from ringbuffer
+ * 
+ * Waits for the specified time until a new edge gets detected.
+ * If not configured otherwise, the pulse duration will be in picosecond resolution.
+ * If a bittime was configured, the return value will contain the properly rounded
+ * number of bit times measured.
+ * 
+ * @param[in]  signal      previously allocated PulseReader object.
+ * @param[in]  timeout_us  time to wait for a signal [µs]
+ * 
+ * @returns the scaled value of the pulse duration
+ */
+uint32_t pulse_reader_receive(PulseReader* signal, int timeout_us);
+
+
+/** Get available samples
+ * 
+ * Get the number of available samples in the ringbuffer
+ *
+ * @param[in]  signal  previously allocated PulseReader object.
+ * 
+ * @returns the number of samples in buffer
+ */
+uint32_t pulse_reader_samples(PulseReader* signal);
+
+
+/** Set timebase
+ * 
+ * Set the timebase to be used when returning pulse duration.
+ *
+ * @param[in]  signal  previously allocated PulseReader object.
+ * @param[in]  unit  PulseReaderUnit64MHz or PulseReaderUnitPicosecond
+ */
+void pulse_reader_set_timebase(PulseReader* signal, PulseReaderUnit unit);
+
+
+
+/** Set bit time
+ * 
+ * Set the number of timebase units per bit.
+ * When set, the pulse_reader_receive() will return an already rounded
+ * bit count value instead of the raw duration.
+ * 
+ * Set to 1 to return duration again.
+ *
+ * @param[in]  signal    previously allocated PulseReader object.
+ * @param[in]  bit_time  
+ */
+void pulse_reader_set_bittime(PulseReader* signal, uint32_t bit_time);
+
+
+#ifdef __cplusplus
+}
+#endif