1 files changed, 150 insertions, 0 deletions
diff --git a/circuitpython/lib/adafruit_floppy/src/Adafruit_Floppy.h b/circuitpython/lib/adafruit_floppy/src/Adafruit_Floppy.h
new file mode 100644
index 0000000..3e519eb
--- /dev/null
+++ b/circuitpython/lib/adafruit_floppy/src/Adafruit_Floppy.h
@@ -0,0 +1,150 @@
+#ifndef ADAFRUIT_FLOPPY_H
+#define ADAFRUIT_FLOPPY_H
+
+#include "Arduino.h"
+#include <Adafruit_SPIDevice.h>
+// to implement SdFat Block Driver
+#include "SdFat.h"
+#include "SdFatConfig.h"
+
+#define FLOPPY_IBMPC_HD_TRACKS 80
+#define FLOPPY_IBMPC_DD_TRACKS 40
+#define FLOPPY_HEADS 2
+
+#define MFM_IBMPC1440K_SECTORS_PER_TRACK 18
+#define MFM_IBMPC360K_SECTORS_PER_TRACK 9
+#define MFM_BYTES_PER_SECTOR 512UL
+
+#ifdef BUSIO_USE_FAST_PINIO
+#define FLOPPYIO_SAMPLERATE (F_CPU * 11u / 90u) // empirical on SAM D51 @ 120MHz
+#endif
+
+#if defined(ARDUINO_ARCH_RP2040)
+#undef FLOPPYIO_SAMPLERATE
+#define FLOPPYIO_SAMPLERATE (F_CPU * 13u / 100u) // empirical on RP2040 @ 200MHz
+#endif
+
+#define T2_5_IBMPC_HD (FLOPPYIO_SAMPLERATE * 5 / 2 / 1000000)
+#define T3_5_IBMPC_HD (FLOPPYIO_SAMPLERATE * 7 / 2 / 1000000)
+#define T2_5_IBMPC_DD (T2_5_IBMPC_HD * 2)
+#define T3_5_IBMPC_DD (T3_5_IBMPC_HD * 2)
+
+#define STEP_OUT HIGH
+#define STEP_IN LOW
+#define MAX_FLUX_PULSE_PER_TRACK                                               \
+  (uint32_t)(500000UL / 5 *                                                    \
+             1.5) // 500khz / 5 hz per track rotation, 1.5 rotations
+
+#define BUSTYPE_IBMPC 1
+#define BUSTYPE_SHUGART 2
+
+typedef enum {
+  IBMPC1440K,
+  IBMPC360K,
+} adafruit_floppy_disk_t;
+
+/**************************************************************************/
+/*!
+    @brief A helper class for chattin with floppy drives
+*/
+/**************************************************************************/
+class Adafruit_Floppy {
+public:
+  Adafruit_Floppy(int8_t densitypin, int8_t indexpin, int8_t selectpin,
+                  int8_t motorpin, int8_t directionpin, int8_t steppin,
+                  int8_t wrdatapin, int8_t wrgatepin, int8_t track0pin,
+                  int8_t protectpin, int8_t rddatapin, int8_t sidepin,
+                  int8_t readypin);
+  void begin(void);
+  void soft_reset(void);
+
+  void select(bool selected);
+  bool spin_motor(bool motor_on);
+  bool goto_track(uint8_t track);
+  void side(uint8_t head);
+  int8_t track(void);
+  void step(bool dir, uint8_t times);
+
+  uint32_t read_track_mfm(uint8_t *sectors, size_t n_sectors,
+                          uint8_t *sector_validity);
+  uint32_t capture_track(uint8_t *pulses, uint32_t max_pulses)
+      __attribute__((optimize("O3")));
+  void print_pulse_bins(uint8_t *pulses, uint32_t num_pulses,
+                        uint8_t max_bins = 64);
+  void print_pulses(uint8_t *pulses, uint32_t num_pulses);
+
+  int8_t led_pin = LED_BUILTIN; ///< Debug LED output for tracing
+
+  uint16_t select_delay_us = 10;  ///< delay after drive select (usecs)
+  uint16_t step_delay_us = 10000; ///< delay between head steps (usecs)
+  uint16_t settle_delay_ms = 15;  ///< settle delay after seek (msecs)
+  uint16_t motor_delay_ms = 1000; ///< delay after motor on (msecs)
+  uint16_t watchdog_delay_ms =
+      1000; ///< quiescent time until drives reset (msecs)
+  uint8_t bus_type = BUSTYPE_IBMPC; ///< what kind of floppy drive we're using
+
+  Stream *debug_serial = NULL; ///< optional debug stream for serial output
+
+private:
+  void wait_for_index_pulse_low(void);
+
+  // theres a lot of GPIO!
+  int8_t _densitypin, _indexpin, _selectpin, _motorpin, _directionpin, _steppin,
+      _wrdatapin, _wrgatepin, _track0pin, _protectpin, _rddatapin, _sidepin,
+      _readypin;
+
+  int8_t _track = -1;
+
+#ifdef BUSIO_USE_FAST_PINIO
+  BusIO_PortReg *indexPort;
+  BusIO_PortMask indexMask;
+#endif
+};
+
+/**************************************************************************/
+/*!
+    This class adds support for the BaseBlockDriver interface to an MFM
+    encoded floppy disk. This allows it to be used with SdFat's FatFileSystem
+   class. or for a mass storage device
+*/
+/**************************************************************************/
+class Adafruit_MFM_Floppy : public BaseBlockDriver {
+public:
+  Adafruit_MFM_Floppy(Adafruit_Floppy *floppy,
+                      adafruit_floppy_disk_t format = IBMPC1440K);
+
+  bool begin(void);
+  bool end(void);
+
+  uint32_t size(void);
+  int32_t readTrack(uint8_t track, bool head);
+
+  /**! @brief The expected number of sectors per track in this format
+       @returns The number of sectors per track */
+  uint8_t sectors_per_track(void) { return _sectors_per_track; }
+  /**! @brief The expected number of tracks per side in this format
+       @returns The number of tracks per side */
+  uint8_t tracks_per_side(void) { return _tracks_per_side; }
+
+  //------------- SdFat BaseBlockDRiver API -------------//
+  virtual bool readBlock(uint32_t block, uint8_t *dst);
+  virtual bool writeBlock(uint32_t block, const uint8_t *src);
+  virtual bool syncBlocks();
+  virtual bool readBlocks(uint32_t block, uint8_t *dst, size_t nb);
+  virtual bool writeBlocks(uint32_t block, const uint8_t *src, size_t nb);
+
+  /**! The raw byte decoded data from the last track read */
+  uint8_t track_data[MFM_IBMPC1440K_SECTORS_PER_TRACK * MFM_BYTES_PER_SECTOR];
+
+  /**! Which tracks from the last track-read were valid MFM/CRC! */
+  uint8_t track_validity[MFM_IBMPC1440K_SECTORS_PER_TRACK];
+
+private:
+  uint8_t _sectors_per_track = 0;
+  uint8_t _tracks_per_side = 0;
+  int8_t _last_track_read = -1; // last cached track
+  Adafruit_Floppy *_floppy = NULL;
+  adafruit_floppy_disk_t _format = IBMPC1440K;
+};
+
+#endif