378 lines
21 KiB
Markdown
378 lines
21 KiB
Markdown
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# ArduinoFDC
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ArduinoFDC is a sketch that implements a floppy disk controller. It works with Arduino Uno, Leonardo, Nano, Pro Mini, Micro and Mega.
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ArduinoFDC consists of three parts:
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1. A [library](#library-functions) providing low-level functions to allow reading and writing disks at the
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sector level as well as low-level formatting disks.
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2. Integration of ChaN's brilliant [FatFS](http://elm-chan.org/fsw/ff/00index_e.html)
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library to provide file-level functions for reading and writing files and directories
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in a FAT (MS-DOS) file system and a high-level format function to initialize a FAT file system.
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3. An example sketch implementing [ArduDOS](#ardudos), a (very) small DOS environment for browsing
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a FAT file system as well as a [low-level disk monitor](#low-level-disk-monitor) to access sector data on the disk,
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including the ability to transfer whole disks or single files via the XModem protocol.
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ArduinoFDC works with double density (DD) as well as high density (HD)
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disk drives. It can read, write and format 5.25" DD (360KB), 5.25" HD (1.2MB), 3.5" DD (720KB)
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and 3.5" HD (1.44MB) disks.
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## Wiring:
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The table below shows how to wire the Arduino pins to the 34-pin IDC
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connector on the floppy drive cable.
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The pin numbers are defined at the top of the ArduinoFDC.cpp file. Some of them can
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easily be changed whereas others are hard-coded in the controller code. Refer to
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the comments at the top of the ArduinoFDC.cpp file if you want to use different
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pin assignments.
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Floppy Cable | Uno/Mini/Nano | Leonardo/Micro | Mega | Notes | Function
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-----------------|---------------|-----------------|--------|--------|---------------
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2 | 13 | 13/16 | 42 | 3,4,5 | Density select
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8 | 7 | 8 | 47 | | Index
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10 | 4 | 5 | 51 | 1,3 | Motor Enable A
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12 | A1 | A1 | 40 | 1,3,4 | Drive Select B
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14 | 5 | 6 | 50 | 1,3 | Drive Select A
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16 | A0 | A0 | 41 | 1,3,4 | Motor Enable B
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18 | 3 | 3 | 52 | 3 | Head Step Direction
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20 | 2 | 2 | 53 | 3 | Head Step Pulse
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22 | 9 | 9 | 46 | | Write Data
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24 | 10 | 10 | 45 | | Write Gate
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26 | 11 | 11/14 | 44 | 3 | Track 0
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28 | 12 | 12/15 | 43 | 3,4 | Write Protect
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30 | 8 | 4 | 48 | 2 | Read Data
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32 | 6 | 7 | 49 | 3 | Side Select
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1,3,5,...,31,33 | GND | GND | GND | 6 | Signal Ground
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**Note 1:**
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The pin numbers for the SELECT/MOTOR signals assume you are wiring to
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the controller end of a floppy drive cable. If you are wiring directly
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to the floppy drive, the A/B pins will be reversed (search the web
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for "Floppy drive twist" for more information).
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**Note 2:**
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It is **highly** recommended (but not entirely necessary) to add a 1k
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pull-up resistor to +5V to this signal. The Arduino's built-in pull-up
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resistors are very weak (20-50k) and may not pull the signal up quickly enough.
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Without the resistor you may encounter read errors (bad CRC, header not found),
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especially when reading HD disks. Whether it works without the resistor will
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depend on your specific drive, drive cable, connections and Arduino.
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**Note 3:**
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This signal can easily be moved to a different pin on the Arduino by
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changing the corresponding `#define PIN_XXX ...` statement at the top
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of ArduinoFDC.cpp
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**Note 4:**
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This signal is not essential for the functionality of the controller.
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The corresponding pin can be freed by commenting out the `#define PIN_XXX ...`
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statement at the top of ArduinoFDC.cpp
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**Note 5:**
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See section "DENSITY control signal" below.
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**Note 6:**
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You should be able to just pick one of the GND pins. However, some cables/drives
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do not actually connect all of these to ground. If your setup does not work
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it may be worth trying a different GND pin.
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## Supported disk/drive types
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To properly read/write data, the library must be configured for the drive/disk
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combination that is being used. The drive type can be passed into the `begin` functions
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or set afterwards by calling the `setDriveType` function. Supported types are:
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* **ArduinoFDC::DT_5_DD**: Double-density disk in a 5.25" double-density drive
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* **ArduinoFDC::DT_5_DDonHD**: Double-density disk in a 5.25" high-density drive
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* **ArduinoFDC::DT_5_HD**: High-density disk in a 5.25" high-density drive
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* **ArduinoFDC::DT_3_DD**: Double-density disk in a 3.5" double- or high-density drive
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* **ArduinoFDC::DT_3_HD**: High-density disk in a 3.5" high-density drive
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## DENSITY control signal
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The function of the DENSITY control signal line between the controller and the
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floppy drive is not well defined and varies between drives. Furthermore most drives
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can be configured by jumpers (also called "straps"). You may want to consult the
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documentation for your drive for details.
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In their default configuration most 3.5" drives do not use this signal. The drive
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itself determines the type of disk (DD or HD) by the presence of a hole in the disk
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(on the opposite edge from the "write protect" hole). The controller must be configured
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separately for the correct type (DD or HD), otherwise reading/writing will fail.
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For 5.25" HD drives this signal is generally an input from the controller to the drive.
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If the signal is LOW then low density mode is selected, otherwise high density is used.
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However, for some drives the opposite is true. Many drives can be configured via jumpers
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to select the expected levals.
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The controller can be configured what to do with this signal by calling the "setDensityPinMode"
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function. The following modes are supported:
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* **ArduinoFDC::DP_DISCONNECT**: This configures the DENSITY pin as INPUT. It does not actually read the pin.
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* **ArduinoFDC::DP_OUTPUT_LOW_FOR_HD**: This configures the DENSITY pin as an OUTPUT and sets it LOW if the disk type is HD.
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* **ArduinoFDC::DP_OUTPUT_LOW_FOR_DD**: This configures the DENSITY pin as an OUTPUT and sets it LOW if the disk type is DD.
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By default, the mode is set to DP_DISCONNECT for 3.5" drives and DP_OUTPUT_LOW_FOR_DD for 5.25" drives.
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Another way to handle the DENSITY signal is to comment out the `#define PIN_DENSITY` line
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at the top of ArduinoFDC.cpp and hard-wire the DENSITY signal from the disk drive cable
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to the proper level (or leave it disconnected).
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## Library functions:
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To use the low-level disk access library functions (listed below), copy ArduinoFDC.h and ArduinoFDC.cpp
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into your Arduino sketch directory and add `#include "ArduinoFDC.h"` to your sketch.
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To use the FAT file system functions, additionally copy ff.h, ff.c, ffconf.h, diskio.h and diskio.cpp.
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Then add `#include "ff.h"` and `#include "ArduinoFDC.h"` to your sketch. For documentation of the FatFS
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functions refer to the [FatFS documentation](http://elm-chan.org/fsw/ff/00index_e.html).
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#### `void ArduinoFDC.begin(driveAtype, driveBtype)`
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Initializes the Arduino pins used by the controller. For possible drive types see
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the "[Supported disk/drive types](#supported-diskdrive-types)" section above. If left out both types default to
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ArduinoFDC::DT_3_HD.
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#### `void ArduinoFDC.end()`
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Releases the pins initialized by ArduinoFDC.begin()
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#### `bool ArduinoFDC.selectDrive(byte drive)`
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Selects drive A (0) or B (1) to be used for subsequent calls to
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readSector/writeSector/formatDisk. Calling `begin()` selects drive A.
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Returns 'false' if trying to select drive 1 when the corresponding control
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pins are commented out in ArduinoFDC.cpp
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#### `byte ArduinoFDC.selectedDrive()`
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Returns which drive is currently selected, A (0) or B (1).
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#### `void ArduinoFDC.setDriveType(driveType)`
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Sets the disk/drive type for the currently selected drive. For possible drive types see
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the "[Supported disk/drive types](#supported-diskdrive-types)" section above.
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#### `byte ArduinoFDC.getDriveType(driveType)`
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Returns the drive type of the currently selected drive.
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#### `void ArduinoFDC.setDensityPinMode(mode)`
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Sets the function of the DENSITY pin for the currently selected drive.
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See section "[Density control signal](#density-control-signal)" above.
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#### `byte ArduinoFDC.numTracks()`
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Returns the number of tracks for the drive type of the currently selected drive.
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#### `byte ArduinoFDC.numSectors()`
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Returns the number of sectors per track for the drive type of the currently selected drive.
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#### `bool ArduinoFDC.haveDisk()`
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Returns true if a disk is in the drive. This is done by looking for the index
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hole. If the drive motor is not currently running this haveDisk() will temporarily
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turn it on.
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#### `bool ArduinoFDC.isWriteProtected()`
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Returns true if the disk is write protected. If no disk is in the drive then
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the result may be either true or false. If the WRITE PROTECT signal is not connected
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then the result is always false.
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#### `void ArduinoFDC.motorOn()`
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Turns the disk drive motor on.
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The `readSector`/`writeSector`/`formatDisk` functions will turn the motor on **and** back off
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automatically if it is not already running. Note that turning on the motor also includes
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a one second delay to allow it to spin up. If you are reading/writing multiple sectors
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you may want to use the `motorOn` and `motorOff` functions to manually turn the motor on
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and off.
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#### `void ArduinoFDC.motorOff()`
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Turns the disk drive motor off.
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#### `bool ArduinoFDC.motorRunning()`
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Returns *true* if the disk drive motor is currently running and *false* if not.
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#### `byte ArduinoFDC.readSector(byte track, byte side, byte sector, byte *buffer)`
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Reads data from a sector from the flopy disk. Always reads a full sector (512 bytes).
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* The "track" parameter must be in range 0..(numTracks()-1)
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* The "side" parameter must either be 0 or 1
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* The "sector" paramter must be in range 1..numSectors()
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* The "buffer" parameter must be a pointer to a byte array of size (at least) 516 bytes.
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The function returns 0 if reading succeeded. Otherwise an error code is returned
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(see [Troubleshooting](#troubleshooting) section below)
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**IMPORTANT:** On successful return, the sector data that was read will be in buffer[1..512] (**NOT** buffer[0..511])
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#### `byte ArduinoFDC.writeSector(byte track, byte side, byte sector, byte *buffer, bool verify)`
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Writes data to a sector on the floppy disk. Always writes a full sector (512 bytes).
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* The "track" parameter must be in range 0..(numTracks()-1)
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* The "side" parameter must either be 0 or 1
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* The "sector" paramter must be in range 1..numSectors()
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* The "buffer" parameter must be a pointer to a byte array of size (at least) 516 bytes.
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* If the "verify" parameter is *true*, the data written will be read back and compared to what was written.
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If a difference is detected then the function will return *false*.
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If the "verify" parameter is *false* then no verification is done. The function may still return *false*
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if the proper sector location on disk can not be found before writing.
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The function returns 0 if writing succeeded. Otherwise an error code is returned
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(see [Troubleshooting](#troubleshooting) section below)
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**IMPORTANT:** The sector data to be written must be in buffer[1..512] (**NOT** buffer[0..511])
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#### `bool ArduinoFDC.formatDisk(byte *buffer, byte from_track=0, byte to_track=255)`
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Formats a floppy disk according to the format specified by the "setDriveType()" function.
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A subset of tracks can be formatted by specifying the from_track and to_track parameters.
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A buffer of size at least 144 bytes is needed to store temporary data during formatting.
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The buffer is passed in as an argument to allow re-using other buffers in your sketch.
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If you do not have a buffer to be re-used, just declare `byte buffer[144]` before calling formatDisk().
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This function does **not** set up any file system on the disk. It only sets up the
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low-level sector structure that allows reading and writing of sectors (and fills all
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sector data with 0xF6 bytes).
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The function returns 0 if formatting succeeded. Otherwise an error code is returned
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(see [Troubleshooting](#troubleshooting) section below). Note that no verification of the formatted disk
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is performed. The only possible error conditions are missing track 0 or index hole signals.
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You can use the `readSector`function to verify that data can be read properly
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after formatting.
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## ArduDOS
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ArduDOS is a minimal DOS that allows the user to browse the file system
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on the disk and read/write files. The basic functionality is modeled on MS-DOS
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with some exceptions:
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1. All commands operate **only** on the currently selected drive. If two drives are
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connected then use "b:" or "a:" to switch drives.
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2. The working directory is **always** the top-level directory of the disk. No "cd"
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command is available to change the directory. Therefore, all paths given as
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arguments to commands must be relative to the top-level directory.
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3. Disk changes are **not** automatically detected. After changing a disk, re-select
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the current drive (e.g. "a:") to notify ArduDOS of the change.
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ArduDOS is easy to access from either Arduio's serial monitor or any other
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serial terminal. Set the monitor or terminal's baud rate to 115200 before connecting.
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The following commands are available:
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* `dir [directory]` <br/>
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Show the listing of the specified directory (default is root directory).
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* `type filename` <br/>
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Type out the specified file to the screen (best for text files).
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* `dump filename` <br/>
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Dump the specified file to the screen in hexadecimal notation (best for binary files).
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* `write filename` <br/>
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Receive text line-by-line from the user and write it to the specified file.
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Enter an empty line to finish.
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* `del filename` <br/>
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Delete the specified file.
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* `mkdir dirname` <br/>
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Create the specified directory.
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* `rmdir dirname` <br/>
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Remove the specified directory.
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* `disktype 0/1/2/3/4` <br/>
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Set the drive type of the current drive, where 0/1/2/3/4 stands for the drive type
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as listed (in the same order) in section "[Supported disk/drive types](#supported-diskdrive-types)" above.
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* `format [/q]` <br/>
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Low-level format a disk and initialize a FAT file system. If `/q` argument is given,
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performs a quick format, i.e. only resets the file system without low-level format.
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* `monitor` <br/>
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Enter the low-level disk monitor (see the "[Low-level disk monitor](#low-level-disk-monitor)" section below).
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* `send filename` (only available if `#define USE_XMODEM` is enabled at the top of ArduinoFDC.ino)<br/>
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Send the specified file via XModem protocol. See the "[XModem](#xmodem)" section below for more details.
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* `receive filename` (only available if `#define USE_XMODEM` is enabled at the top of ArduinoFDC.ino)<br/>
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Receive the specified file via XModem protocol. See the "[XModem](#xmodem)" section below for more details.
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## Low-level disk monitor
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Like ArduDOS, the low-level monitor is easy to use with the Arduino serial monitor.
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When using ArduDOS (i.e. `#define USE_ARDUDOS` is enabled at the top of ArduinoFDC.ino),
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use the "monitor" command to enter the low-level monitor.
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If ArduDOS is not enabled then the sketch drops directly into the disk monitor mode.
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Set Arduino's serial monitor to 115200 baud to connect.
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When running, the monitor will show a command prompt. Enter your command in the
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serial monitor's input line and press *Enter* to execute the command.
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The following commands are supported:
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* `r track, sector[,side]` <br/>
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Read the sector specified by track/sector/side, copy its contents to an internal
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buffer and show the buffer content. If the *side* parameter is left out it defaults
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to zero.
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* `w track, sector[,side]` <br/>
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Write the current buffer contents to the sector specified by track/sector/side
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and verify the data after writing. Shows "Ok" or "Error" status after execution.
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If the *side* parameter is left out it defaults to zero.
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* `f` <br/>
|
||
|
|
Low-level format the disk. No file system is initialized, all sectors are filled
|
||
|
|
with 0xF6. To format and/or add a file system use the "format" command in ArduDOS
|
||
|
|
(see ArduDOS section above).
|
||
|
|
* `b` <br/>
|
||
|
|
Show the current buffer content
|
||
|
|
* `B [n]` <br/>
|
||
|
|
Fill the buffer with value *n*. If *n* is left out then fill the buffer with
|
||
|
|
bytes 0,1,2,...255,0,1,2,...255.
|
||
|
|
* `m [0/1]` <br/>
|
||
|
|
Turn the motor of the currently selected drive off/on. If the *0/1* parameter is left out
|
||
|
|
then the current motor status is shown.
|
||
|
|
* `r` <br/>
|
||
|
|
Read ALL sectors on the disk and show status Ok/Error for each one.
|
||
|
|
* `w [0/1]` <br/>
|
||
|
|
Write the current buffer content to ALL sectors on the disk. If the *0/1* parameter
|
||
|
|
is 1 then verify every sector after writing it (significantly slower).
|
||
|
|
If the *0/1* parameter is left out it defaults to 0.
|
||
|
|
* `s [0/1]` <br/>
|
||
|
|
Select drive A (0) or B (1). If the *0/1* parameter is left out then the currently
|
||
|
|
selected drive is shown.
|
||
|
|
* `t 0/1/2/3/4` <br/>
|
||
|
|
Set the drive type of the current drive, where 0/1/2/3/4 stands for the drive type
|
||
|
|
as listed (in the same order) in section "[Supported disk/drive types](#supported-diskdrive-types)" above.
|
||
|
|
* `S` (only available if `#define USE_XMODEM` is enabled at the top of ArduinoFDC.ino)</br>
|
||
|
|
Read all sectors of the current disk and transmit them via XModem protocol. See
|
||
|
|
the "[XModem](#xmodem)" section below for more details.
|
||
|
|
* `R` (only available if `#define USE_XMODEM` is enabled at the top of ArduinoFDC.ino)</br>
|
||
|
|
Receive a disk image via XModem and write it to the current disk. See
|
||
|
|
the "[XModem](#xmodem)" section below for more details.
|
||
|
|
* `x` (only if the monitor is entered from ArduDOS via the "monitor" command)</br>
|
||
|
|
Exit the monitor and return to [ArduDOS](#ardudos).
|
||
|
|
|
||
|
|
## XModem
|
||
|
|
|
||
|
|
Both ArduDOS and the low-level monitor can transmit and receive data via the XModem protocol.
|
||
|
|
If you want to use this functionality, first un-comment the `#define USE_XMODEM` setting at
|
||
|
|
the top of file ArduinoFDC.ino and re-upload the sketch.
|
||
|
|
|
||
|
|
Use a terminal program that supports XModem to send/receive the data. I recommend TeraTerm.
|
||
|
|
First start the transfer on the controller then initiate the XModem send/receive function in
|
||
|
|
the terminal program.
|
||
|
|
|
||
|
|
Note that *no error messages* can be displayed during the XModem transfers since the transfer
|
||
|
|
takes place over the same serial connection as the terminal. If the transfer stops prematurely
|
||
|
|
and nothing is shown in the terminal, pressing ENTER will get the command prompt back.
|
||
|
|
|
||
|
|
## Troubleshooting
|
||
|
|
|
||
|
|
The following table lists the error codes returned by the `readSector`, `writeSector`
|
||
|
|
and `formatDisk` functions including possible causes for each error. Pin numbers refer
|
||
|
|
to pins on the Arduino UNO.
|
||
|
|
|
||
|
|
\# | Code | Meaning | Possible causes
|
||
|
|
--|-------------|---------|----------------
|
||
|
|
0 | S_OK | No error, the operation succeeded |
|
||
|
|
1 | S_NOTINIT | The ArduinoFDC.begin() function has not been called |
|
||
|
|
2 | S_NOTREADY | No data at all is received from the disk drive | - no disk in drive <br/> - drive does not have power <br/> - pins MOTOR (4/12), SELECT (5/13), READ (8), INDEX (7) or GND not properly connected
|
||
|
|
3 | S_NOSYNC | Data is received but no sync mark can be found | - disk not formatted or not formatted for the correct density <br/> - GND pin not properly connected
|
||
|
|
4 | S_NOHEADER | Sync marks are found but either no sector header or no header with the expected track/side/sector markings | - pins STEP (2), STEPDIR (3), SIDE (6) or GND not properly connected <br/> - bad disk or unknown format <br/> - misaligned disk drive<br/> - invalid track, sector or head number given
|
||
|
|
5 | S_INVALIDID | The data record was not started by a 0xFB byte as expected | - bad disk or unknown format
|
||
|
|
6 | S_CRC | The sector data checksum is incorrect | - bad disk or unknown format <br/> - pullup resistors too weak (see note 2 in wiring section)
|
||
|
|
7 | S_NOTRACK0 | When trying to move the read head to track 0, the TRACK0 signal was not seen, even after stepping more than 80 tracks. | - pins STEP (2), STEPDIR (3), SELECT (5/13), TRACK0 (11) or GND not properly connected <br/> - drive does not have power
|
||
|
|
8 | S_VERIFY | When reading back data that was just written, the data did not match | - pins WRITEGATE (10) or WRITEDATA (9) not properly connected<br/>- disk is write protected and WRITEPROTECT (12) pin is not connected <br/> - bad disk
|
||
|
|
9 | S_READONLY | Attempting to write to a write-protected disk | - disk is write protected
|
||
|
|
|
||
|
|
## Acknowledgements
|
||
|
|
|
||
|
|
The ArduDOS functionality would not have been possible without ChaN's brilliant [FatFS](http://elm-chan.org/fsw/ff/00index_e.html) library.
|
||
|
|
|
||
|
|
The XModem communication uses the arduino-xmodem code available at https://code.google.com/archive/p/arduino-xmodem.
|