explain the initialization sequence

Fix the `ocamlwiring_pull_up_dn_control` stub

.gitignore

@@ -1,4 +1,12 @@
-/_build/
-/_opam/
-.merlin
-*.install
+*.mllib
+*.mldylib
+*.clib
+META
+Makefile
+configure
+_tags
+setup.ml
+setup.data
+setup.log
+myocamlbuild.ml
+_build/

Makefile

@@ -1,11 +0,0 @@
-.PHONY: all
-all:
-	jbuilder build --dev
-
-.PHONY: clean
-clean:
-	jbuilder clean
-
-.PHONY: test
-test:
-	jbuilder runtest --force

_oasis

@@ -0,0 +1,35 @@
+OASISFormat: 0.4
+Name:        WiringPi
+Version:     0.0.1
+Synopsis:    Binding to the WiringPi library for hardware access
+Authors:     Tobias Bora, Marek Kubica
+License:     LGPL-3 with OCaml linking exception
+Plugins:     META (0.4), DevFiles (0.4)
+
+Library "WiringPi"
+  Path:       src/
+  BuildTools: ocamlbuild
+  Modules:    WiringPi, Gpio3
+  CSources:   WiringPi_stubs.c
+  CCLib:      -lwiringPi
+
+Executable "wpi-button-example"
+  Path:         examples/
+  BuildTools:   ocamlbuild
+  MainIs:       button.ml
+  BuildDepends: WiringPi,unix
+
+Executable "adafruit-lcd-example"
+  Path:         examples/
+  BuildTools:   ocamlbuild
+  MainIs:       lcd_example.ml
+  BuildDepends: WiringPi,unix
+
+Executable "adafruit-lcd-server"
+  CompiledObject: native
+  Path:         examples/
+  BuildTools:   ocamlbuild
+  MainIs:       lcd_lwt.ml
+  BuildDepends: WiringPi,unix,lwt,lwt.unix,threads
+  CCLib:      -lwiringPi
+

examples/button.ml

@@ -0,0 +1,22 @@
+open Gpio3
+
+(* Set up the pins the following way: *)
+(* pin 3 (pull-up) -> btn -> resistor -> gnd *)
+
+let setup () =
+  Gpio3.setup ();
+  pin_mode GPIO3 IN;
+  pull_up_dn_control GPIO3 UP
+
+let rec loop () =
+  (match digital_read GPIO3 with
+   | LOW -> print_endline "-- LOW"
+   | HIGH -> print_endline "++ HIGH");
+  Unix.sleepf 0.5;
+  loop ()
+
+
+let _ =
+  setup ();
+  loop ();
+

examples/lcd.ml

@@ -0,0 +1,125 @@
+(** An example with Adafruit character LCD, HD44780. *)
+(* The documentation: https://cdn-shop.adafruit.com/datasheets/HD44780.pdf *)
+open Gpio3
+
+(** Parameters *)
+type mono_lcd = {
+    columns: int;
+    rows: int;
+    rs: pin;
+    en: pin;
+    d4: pin;
+    d5: pin;
+    d6: pin;
+    d7: pin
+}
+
+(** MAGIC NUMBERS *)
+(* Commands *)
+let _lcd_cleardisplay        = (0x01)
+let _lcd_returnhome          = (0x02)
+let _lcd_entrymodeset        = (0x04)
+let _lcd_displaycontrol      = (0x08)
+let _lcd_cursorshift         = (0x10)
+let _lcd_functionset         = (0x20)
+let _lcd_setcgramaddr        = (0x40)
+let _lcd_setddramaddr        = (0x80)
+
+(* Entry flags *)
+let _lcd_entryleft           = (0x02)
+let _lcd_entryshiftdecrement = (0x00)
+
+(* Control flags *)
+let _lcd_displayon           = (0x04)
+let _lcd_cursoron            = (0x02)
+let _lcd_cursoroff           = (0x00)
+let _lcd_blinkon             = (0x01)
+let _lcd_blinkoff            = (0x00)
+
+(* Move flags *)
+let _lcd_displaymove         = (0x08)
+let _lcd_moveright           = (0x04)
+let _lcd_moveleft            = (0x00)
+
+(* Function set flags *)
+let _lcd_4bitmode            = (0x00)
+let _lcd_2line               = (0x08)
+let _lcd_1line               = (0x00)
+let _lcd_5x8dots             = (0x00)
+
+(* Offset for up to 4 rows. *)
+let _lcd_row_offsets = [|0x00; 0x40; 0x14; 0x54|]
+
+let pulse_enable lcd =
+  digital_write lcd.en LOW;
+  (* 1 microsec pause *)
+  Unix.sleepf(0.0000001);
+  digital_write lcd.en HIGH;
+  Unix.sleepf(0.0000001);
+  digital_write lcd.en LOW;
+  Unix.sleepf(0.00001)
+
+(** write 8 bits of data *)
+let write8 lcd ?(char_mode=false) value =
+  (* one ms delay to prevent writing too quickly *)
+  Unix.sleepf(0.001);
+  let char_mode_value = if char_mode then HIGH else LOW in
+  digital_write lcd.rs char_mode_value;
+  let val_of_int i = if i > 0 then HIGH else LOW in
+  let ival = Char.code value in
+  (* write the UPPER 4 bits (in reverse order) *)
+  digital_write lcd.d4 (val_of_int ((ival lsr 4) land 1));
+  digital_write lcd.d5 (val_of_int ((ival lsr 5) land 1));
+  digital_write lcd.d6 (val_of_int ((ival lsr 6) land 1));
+  digital_write lcd.d7 (val_of_int ((ival lsr 7) land 1));
+  pulse_enable lcd;
+  (* write the LOWER 4 bits *)
+  digital_write lcd.d4 (val_of_int (ival land 1));
+  digital_write lcd.d5 (val_of_int ((ival lsr 1) land 1));
+  digital_write lcd.d6 (val_of_int ((ival lsr 2) land 1));
+  digital_write lcd.d7 (val_of_int ((ival lsr 3) land 1));
+  pulse_enable lcd
+
+(** same as [write8] but write an int (must be within the range) *)
+let write8_unsafe lcd ?(char_mode=false) ival =
+  write8 lcd ~char_mode (Char.unsafe_chr ival)
+
+let setup lcd =
+  Gpio3.setup ();
+  pin_mode lcd.rs OUT;
+  pin_mode lcd.en OUT;
+  pin_mode lcd.d4 OUT;
+  pin_mode lcd.d5 OUT;
+  pin_mode lcd.d6 OUT;
+  pin_mode lcd.d7 OUT;
+  (* send the 4-bit initialization sequence: 0011, 0011, 0011, 0010.
+     see Figure 24 in the docs. *)
+  write8_unsafe lcd 0x33;
+  write8_unsafe lcd 0x32;
+  (* set up some stuff *)
+  let displayctrl = _lcd_displayon lor _lcd_cursoroff lor _lcd_blinkoff in
+  let displayfn = _lcd_4bitmode lor _lcd_2line lor _lcd_5x8dots in
+  let displaymode = _lcd_entryleft lor _lcd_entryshiftdecrement in
+  write8_unsafe lcd (displayctrl lor _lcd_displaycontrol);
+  write8_unsafe lcd (displayfn lor _lcd_functionset);
+  write8_unsafe lcd (displaymode lor _lcd_entrymodeset);
+  Unix.sleepf(0.003)
+
+let clear lcd =
+  write8_unsafe lcd _lcd_cleardisplay;
+  Unix.sleepf(0.003)
+
+let shift_left lcd =
+  write8_unsafe lcd (_lcd_cursorshift lor _lcd_displaymove lor _lcd_moveleft)
+
+let shift_right lcd =
+  write8_unsafe lcd (_lcd_cursorshift lor _lcd_displaymove lor _lcd_moveright)
+
+let set_position lcd x y =
+  let c = x mod lcd.columns in
+  let r = y mod lcd.rows in
+  if (c < 0 || r < 0) then failwith "Lcd.set_position: Negative row or column";
+  write8_unsafe lcd (_lcd_setddramaddr lor (c + _lcd_row_offsets.(r)))
+
+let write_bytes lcd bts =
+  Bytes.iter (fun c -> write8 lcd c ~char_mode:true) bts

examples/lcd_example.ml

@@ -0,0 +1,20 @@
+(** An example with Adafruit character LCD, HD44780. *)
+open Gpio3
+open Lcd
+
+let lcd = {
+    columns = 16;
+    rows = 2;
+    rs = GPIO20;
+    en = GPIO16;
+    d4 = GPIO19;
+    d5 = GPIO5;
+    d6 = GPIO11;
+    d7 = GPIO10;
+}
+
+let _ =
+  setup lcd;
+  clear lcd;
+  set_position lcd 0 0;
+  write_bytes lcd (Bytes.of_string "Hello, world.")

examples/lcd_lwt.ml

@@ -0,0 +1,152 @@
+(** An example with Adafruit character LCD, HD44780. *)
+open Gpio3
+open Lcd
+open Lwt
+
+let lcd = {
+    columns = 16;
+    rows = 2;
+    rs = GPIO20;
+    en = GPIO16;
+    d4 = GPIO19;
+    d5 = GPIO5;
+    d6 = GPIO11;
+    d7 = GPIO10;
+}
+
+(** A nicer abstraction *)
+module Cursor = struct
+  type t = { x: int; y: int; visible: bool; blink: bool; _lcd: mono_lcd }
+
+  (** Creates a new cursor at the position (0,0) *)
+  let of_lcd lcd =
+    set_position lcd 0 0;
+    { x = 0; y = 0; visible = false; blink = false; _lcd = lcd }
+
+  (** Explicitly set the position of the cursor. The arguments will be
+     taken modulo the size of the LCD. *)
+  let set_position x y cur =
+    let col = x mod cur._lcd.columns in
+    let row = y mod cur._lcd.rows in
+    set_position cur._lcd col row;
+    { cur with x = col; y = row }
+
+  (** Whether to display the cursor *)
+  let set_visible flag cur =
+    let _blinkon = if cur.blink then _lcd_blinkon else _lcd_blinkoff in
+    let _cursoron = if flag then _lcd_cursoron else _lcd_cursoroff in
+    let displayctrl = _lcd_displayon lor _cursoron lor _blinkon in
+    write8_unsafe lcd (displayctrl lor _lcd_displaycontrol);
+    { cur with visible = flag }
+
+  (** Whether the cursor is blinking *)
+  let set_blink flag cur =
+    let _blinkon = if flag then _lcd_blinkon else _lcd_blinkoff in
+    let _cursoron = if cur.visible then _lcd_cursoron else _lcd_cursoroff in
+    let displayctrl = _lcd_displayon lor _cursoron lor _blinkon in
+    write8_unsafe lcd (displayctrl lor _lcd_displaycontrol);
+    { cur with blink = flag }
+
+  (** Try writing a character, optionally with wrapping. *)
+  let write_char wrapping v cur =
+    write8 cur._lcd ~char_mode:true v;
+    let col = cur.x + 1 in
+    if not wrapping || col < cur._lcd.columns
+    then { cur with x = col }
+    else let row = cur.y + 1 in
+         let col = 0 in
+         (* set_position should do the wrapping for us *)
+         set_position col row cur
+
+  let write_bytes wrapping bts cur =
+    let f cur chr =
+      if chr = '\n'
+      then set_position 0 (cur.y + 1) cur
+      else if chr = '\r'
+      then set_position 0 cur.y cur
+      else write_char wrapping chr cur in
+    Seq.fold_left f cur (Bytes.to_seq bts)
+
+  let write_string ?(wrap=false) str cur = write_bytes wrap (Bytes.of_string str) cur
+
+end
+
+(** A useful combinator for the functions from the [Cursor] module *)
+let (|>) (m : Cursor.t) (f : Cursor.t -> 'b) = f m
+
+(** Display two lines without wrapping *)
+let display_lines l1 l2 =
+  let col_shift = 3 in
+  let maxwidth = int_of_float (float_of_int lcd.columns *. 2.5) - col_shift in
+  let trunc str =
+    let n = min maxwidth (String.length str) in
+    String.sub str 0 n
+  in
+  let open Cursor in
+  clear lcd;
+  of_lcd lcd
+  |> set_visible false
+  |> set_blink false
+  |> set_position col_shift 0 
+  |> write_string (trunc l1) ~wrap:false
+  |> set_position col_shift 1
+  |> write_string (trunc l2) ~wrap:false
+
+(** Scrolling thread *)
+
+let rec scroll lcd sleep_for : unit Lwt.t =
+  shift_left lcd;
+  Lwt_unix.sleep sleep_for >>= fun () ->
+  scroll lcd sleep_for
+
+
+(** Networking stuff *)
+
+let create_socket () =
+  let open Lwt_unix in
+  let sock = socket PF_INET SOCK_STREAM 0 in
+  (* let bind_addr = Unix.inet_addr_loopback in *)
+  gethostbyname "balthasar.local" >>= fun bind_addr ->
+  let bind_addr = bind_addr.h_addr_list.(0) in
+  bind sock @@ ADDR_INET(bind_addr, 8080) >>= fun () ->
+  listen sock 10;
+  return sock
+
+let rec handle_message ic oc () =
+  Lwt_io.read_line_opt ic >>= fun line1 ->
+  Lwt_io.read_line_opt ic >>= fun line2 ->
+  match line1,line2 with
+  | Some l1, Some l2 ->
+     Lwt_io.printl "Recieved the following message:" >>= fun () ->
+     Lwt_io.printl l1 >>= fun () ->
+     Lwt_io.printl l2 >>= fun () ->
+     Lwt.async (fun () -> Lwt_io.close oc);
+     ignore (display_lines l1 l2);
+     return ()
+  | _,_ -> return ()
+
+let handle_connection conn =
+  let fd, _ = conn in
+  let ic = Lwt_io.of_fd Lwt_io.Input fd in
+  let oc = Lwt_io.of_fd Lwt_io.Output fd in
+  Lwt.on_failure (handle_message ic oc ())
+    (fun e -> Printf.printf "Error in `handle_message': %s\n" (Printexc.to_string e));
+  return ()
+
+let create_server sock =
+  let rec serve () =
+    Lwt_unix.accept sock >>= handle_connection >>= serve
+  in serve
+
+let main () =
+  Lwt.async (fun () -> scroll lcd 0.7);
+  create_socket () >>= fun sock ->
+  create_server sock ()
+
+
+let _ =
+  setup lcd;
+  clear lcd;
+  ignore (display_lines "Hello, " "world!");
+  Lwt_main.run @@ main ()
+  

pkg/pkg.ml

@@ -1,2 +0,0 @@
-#use "topfind"
-#require "topkg-jbuilder.auto"

src/Gpio3.ml

@@ -0,0 +1,95 @@
+(** Typed interface for WiritngPi.
+ Missing:
+ - modes PWM_OUTPUT and GPIO_GLOCK
+ - pwm_write
+ - digital_write_byte
+ - analog_read
+ - analog_write
+ - delay, delay_microseconds (?)
+ *)
+open WiringPi
+
+let setup () = ignore (setup_gpio ())
+
+type pin =
+ (*  3V3  |  5V   *)
+    GPIO2 | (* 5V *)
+    GPIO3 | (* GND *)
+    GPIO4 | GPIO14
+(* GND *) | GPIO15 |
+   GPIO17 | GPIO18 |
+   GPIO27 | (* GND *)
+   GPIO22 | GPIO23
+(* 3V3 *) | GPIO24 |
+   GPIO10 | (* GND *)
+    GPIO9 | GPIO25 |
+   GPIO11 | GPIO8 
+(* GND *) | GPIO7  |
+    GPIO0 | GPIO1  |
+    GPIO5 | (* GND *)
+    GPIO6 | GPIO12 |
+   GPIO13 | (* GND *)
+   GPIO19 | GPIO16 |
+   GPIO26 | GPIO20
+
+let int_of_pin = function
+  | GPIO2 -> 2
+  | GPIO3 -> 3
+  | GPIO4 -> 4
+  | GPIO14 -> 14
+  | GPIO15 -> 15
+  | GPIO17 -> 17
+  | GPIO18 -> 18
+  | GPIO27 -> 27
+  | GPIO22 -> 22
+  | GPIO23 -> 23
+  | GPIO24 -> 24
+  | GPIO10 -> 10
+  | GPIO9 -> 9
+  | GPIO25 -> 25
+  | GPIO11 -> 11
+  | GPIO8 -> 8
+  | GPIO7 -> 7
+  | GPIO0 -> 0
+  | GPIO1 -> 1
+  | GPIO5 -> 5
+  | GPIO6 -> 6
+  | GPIO12 -> 12
+  | GPIO13 -> 13
+  | GPIO19 -> 19
+  | GPIO16 -> 16
+  | GPIO26 -> 26
+  | GPIO20 -> 20
+
+(* What is not supported: PWM_OUTPUT and GPIO_GLOCK *)
+type mode = IN | OUT
+
+(** [pin_mode] sets the mode of the pin to either input or output
+   (other modes not supported at this moment). *)
+let pin_mode (p : pin) (m : mode) =
+  match m with
+  | IN -> WiringPi.pin_mode (int_of_pin p) 0
+  | OUT -> WiringPi.pin_mode (int_of_pin p) 1
+
+type pin_updn = UP | DOWN | OFF
+
+(** [pull_up_dn_control] sets the pull-up or pull-down resistor mode on
+   the given pin, which should be set as an input. *)
+let pull_up_dn_control (p : pin) = function
+  | UP -> WiringPi.pull_up_dn_control (int_of_pin p) 2
+  | DOWN -> WiringPi.pull_up_dn_control (int_of_pin p) 1
+  | OFF -> WiringPi.pull_up_dn_control (int_of_pin p) 0
+
+type pin_value = LOW | HIGH
+
+(** [digital_write] the value HIGH or LOW to the given pin which must
+   have been previously set as an output. *)
+let digital_write (p : pin) (v : pin_value) =
+  match v with
+  | LOW -> WiringPi.digital_write (int_of_pin p) 0
+  | HIGH -> WiringPi.digital_write (int_of_pin p) 1
+
+let digital_read (p : pin) : pin_value =
+  match WiringPi.digital_read (int_of_pin p) with
+  | 0 -> LOW
+  | _ -> HIGH

src/Gpio3.mli

@@ -0,0 +1,33 @@
+(** broadcom numbers *)
+val setup : unit -> unit
+
+type pin =
+ (*  3V3  |  5V   *)
+    GPIO2 | (* 5V *)
+    GPIO3 | (* GND *)
+    GPIO4 | GPIO14
+(* GND *) | GPIO15 |
+   GPIO17 | GPIO18 |
+   GPIO27 | (* GND *)
+   GPIO22 | GPIO23
+(* 3V3 *) | GPIO24 |
+   GPIO10 | (* GND *)
+    GPIO9 | GPIO25 |
+   GPIO11 | GPIO8 
+(* GND *) | GPIO7  |
+    GPIO0 | GPIO1  |
+    GPIO5 | (* GND *)
+    GPIO6 | GPIO12 |
+   GPIO13 | (* GND *)
+   GPIO19 | GPIO16 |
+   GPIO26 | GPIO20
+
+type pin_value = LOW | HIGH
+
+type mode = IN | OUT
+type pin_updn = UP | DOWN | OFF
+               
+val pin_mode : pin -> mode -> unit
+val pull_up_dn_control : pin -> pin_updn -> unit
+val digital_write : pin -> pin_value -> unit
+val digital_read : pin -> pin_value

src/WiringPi_stubs.c

@@ -45,7 +45,7 @@ value ocamlwiring_pin_mode(value pin, value mode)
 value ocamlwiring_pull_up_dn_control(value pin, value pud)
 {
   CAMLparam2(pin, pud);
-  pullUpDnControl(Int_val(pin), Int_val(pin));
+  pullUpDnControl(Int_val(pin), Int_val(pud));
   CAMLreturn(Val_unit);
 }
 

src/jbuild

@@ -1,3 +0,0 @@
-(library
-  ((name wiringpi)
-   (public_name wiringpi)))

wiringpi.descr

@@ -1,10 +0,0 @@
-WiringPi for OCaml, low level Raspberry Pi hardware access
-WiringPi is a library that allows easy, Arduino-like access to hardware
-functionality (GPIO pins mostly) of the Raspberry Pi minicomputer. That library
-is written in C so what this package does is to provide a simple interface to
-use the C library from OCaml. The API is unchanged (even the capitalization) to
-provide an interface which is as similar as possible to the code that it is
-based upon.
-
-Please note that you need to install the WiringPi library first, as it is not
-included in this package. Otherwise compilation will fail.

wiringpi.opam

@@ -1,16 +0,0 @@
-opam-version: "1.2"
-maintainer: "marek@xivilization.net"
-homepage: "https://github.com/Leonidas-from-XIV/ocaml-wiringpi"
-license: "LGPL-3 with OCaml linking exception"
-build: ["jbuilder" "build" "-p" name "-j" jobs]
-depends: [
-  "jbuilder" {build}
-]
-post-messages: [
-  "
-  This package requires WiringPi development files installed.
-  Tentative instructions : https://gist.githubusercontent.com/Leonidas-from-XIV/a1a7315ac01f7fbee3f0/raw
-  "
-  {failure}
-]
-available: os = "linux"