manual:chapter6:usb:cmd

Synopsis

Receive an object through USB link

Stack Diagram

Input Stack		Output Stack
Num_time-out	→	O	1
Num_time-out	→		0
Level 1	→	Level 2	Level 1

Legend

Legend	Object type
O	Any object
I	Integer number
R	Real number
#	Binary number
Num	Scalar (Integer, Real or Binary number)
Z	Complex number
U	Unit
∡	Angle
A	Symbolic expression
C	Symbolic constant
V	Vector
M	Matrix
S	String
1/0	Any expression evaluating to True or False
G	Grob
F	Font
D	Binary data container
T	Tag object
L	List
cL	Case list
N	Variable name / Identifier
Dir	Directory
pDir	Packed Directory
P	Program
Lib	Library

Type	Command
Parallel list processing	Group 5
Affected by flags	-47	Automatic reception and execution of data sent via USB

Description

The USBRECV command receives an object transmitted by another calculator using the USB link, provided the connection has been successufully negotiated. Since by default object reception happens automatically without an explicit use of USBRECV, the pre-condition for usage of USBRECV is the disabling of automatic reception by setting flag -47.

If the transfer succeeds USBRECV will leave the object 1 on the stack, otherwise it will leave only 0. The incoming object will NOT be XEQted - see USBAUTORCV if this feature is not desired.

The USBRECV command accepts a time-out parameter expressed in seconds. After the time-out elapses USBRECV aborts with a failure. Also, transmission can be interrupted pressing ON before time-out ends.

To signal the user of an incoming object waiting to be received an RX indicator is displayed in the status area.

Compatibility

This command is new in newRPL and does not exist in userRPL.

Usage

The following program

« @@ Send the variable name to the other side
  DO
    DUP 
  UNTIL
    USBSEND
  END
  DROP

 @@ Now create a program to RCL and send back the result...
  «
    RCL 
    DO
      DUP 
    UNTIL
      USBSEND
    END
    DROP 
  »

  @@ ...and send the program to be auto-executed over there
  DO
    DUP 
  UNTIL
    USBSEND
  END
  DROP

  @@ Wait a couple of seconds for the contents to arrive
  IF
    -47 FS?
  THEN
    2 USBRECV
    DROP
  END
»

executes a RCL through USB. See USBSEND for implementation of a USB STO.

Related Commands

USB Communications 8 NEW

Command	Short Description
USBSTATUS	Get status of the USB driver	NEW
USBRECV	Receive an object through USB link	NEW
USBSEND	Send an object through the USB link	NEW
USBOFF	Disable USB port	NEW
USBON	Enable USB port	NEW
USBAUTORCV	Receive an object and execute it	NEW
USBARCHIVE	Create a backup on a remote machine	NEW
USBRESTORE	Restore a backup from a remote machine	NEW