test.ml

open Core.Std
open Lwt

let cmd = "\x00\x00\x00\x00\x00\x00\x00\x00";;

let buf = String.make 500 (char_of_int 0);;

let device = USB.open_device_with ~vendor_id:0x0CA6 ~product_id:0xA010 in
    let t =
      USB.claim_interface device 0

      >>=

        fun u -> (
          USB.bulk_send ~handle:device
                        ~endpoint:0x01 cmd 0 (String.length cmd)
        )

      >>=

        fun s -> (
          if s > 0 then
            USB.bulk_recv ~handle:device ~endpoint:0x81 buf 0 500
          else
            return (-1)
        )

      >>=

        fun r -> (
          r
          |> String.slice buf 0
          |> String.to_list
          |> List.map ~f:(fun c -> Printf.sprintf "%02X" @@ int_of_char c)
          |> String.concat ~sep:" "
          |> print_endline
          |> return
        )

      >>=

        fun u -> USB.release_interface device 0

      >>=

        fun u -> return @@ USB.close device

    in Lwt_main.run t