Macintosh Serial input and output

1. Download and install Keyspan driver for USA-28x USB Twin Serial Adaptor - also for USA-19HS high-speed serial adapter with DTE male connector.
2. plug Keyspan USA-28X USB to Serial adapter into a USB port
3. Run the Keyspan Serial Assistant to check driver installation and port number

1. a program running on the Macintosh - Zterm or one you write
2. an external device that can display characters - dumb terminal or LCD display
3. a cable between the Keyspan USA-28X and the external device

1. Download a copy of Zterm or goSerial (a Cocoa program with similar functionality
2. Setup Zterm as shown in diagrams below
   1. Settings->Modem Preferences - select serial port - use port 1
   2. Settings->Connection - select data format, name device and select echo
3. To commence serial i/o select Dial->Keyspan - should get "Direct Connect Keyspan"
4. Type on Mac keyboard and see characters appear in Zterm window (local echo is on)

1. make a loop back connector to connect Tx to Rx (either to plug into Mini Din8 or DE9 cable)
2. In Zterm, type a character
3. It should appear twice: local echo and loop back

Loop back connections for Mac DE9 cable on right

1. if you have a dumb terminal you can use it (see end of this page for possible cable)
2. otherwise purchase a Scott Edwards BPI 216 serial LCD module, download manual
3. Also available from Parallax and Jameco electronics
4. Images below show data appearing on display (left), Zterm window (right) and connections (middle)

1. Option 1 - cut an apple serial cable (DIN8 to DIN8) in two
   1. solder the wires to the LCD or use a prototypng card
2. Option 2 - use an apple serial DIN8 to Apple DB9 female cable (see R/C servo page)
   1. make a cable with an Apple DB9 male on one end and solder the other end to LCD

• 1&2
• 3&5
• 6&8

1. plug everything together and start Zterm
2. Characters you type on Zterm should appear on the display
3. As the characters will run off the end you need to ............

1. Download the manual
2. Look at LabVIEW program below, and get a copy of LabVIEW student edition

LoopBackTest.vi uses a string but only finds 1 of the 2 Keyspan ports.

See: file for information on using LabVIEW with Intel Macs

1. Code - written in a graphical language
   1. Icons representing functions (vis) are dropped, and
   2. connected using wires representing data flow
2. Front Pannel - graphical user interface, where
   1. user enters data - e.g. selects serial port, and
   2. program outputs results and reports errors etc.

WriteStringLCD.vi (56Kb) - CTRL click to get file

• get a reference to the serial port (VISA resource)
• get the baud rate (9600)
• Configure the serial port
• Combine 4 strings:
  • Instruction
    • ASCII 254 (change to instruction mode)
    • ASCII 129 (move cursor to line 1 character 1)
  • Data - string constant (Welcome to LCD)
  • Instruction
    • ASCII 254 (change to instruction mode)
    • ASCII 195 (move cursor to line 2 character 3)
  • Data - String entered on front pannel (hello Danny)
• write the string of ASCII characters to the serial port
• where it appears on the LCD display

Macintosh Java serial

Installing and testing gnu.io

1. If you havn't installed and tested your serial hardware and driver (Keyspan - see above) and tested it with a loop back cable do so before you go any further.
2. Down load rxtx-2.1-7r2 from RXTX and find in /MACOSX_IDE the files librxtxSerial.jnilib (320Kb) and RXTXcomm.jar (112Kb)
3. Copy them to HardDrive/Library/Java/Extension - where HardDrive is the name of your OSX boot drive
   1. the compiler will find them there without linking them into the project
   2. BUT if you get namespace conflicts you will need to put them elsewhere an link them in XCode
4. Inorder for rxtx-2.1-7 libraries to conform to MacOSX security, spool and lock folders have to be set up:
   1. Run the Terminal utility (/Applications/Utilities/Terminal)
   2. check whether /var/spool/uucp exists
   3. if it doesn't exist then create it
      1. sodo mkdir /var/spool/uucp
         1. sodo - do as super user (admin password); mkdir - make a new directory
      2. sodo chmod g+w /var/spool/uucp
         1. so that permissions are drwxrwxr-x
         2. chmod - change mode (permissions)
   4. check that each intended user is a member of the uucp group
      1. sudo niutil -readprop / /groups/uucp users
   5. if not then make them a member by:
      1. sudo niutil -appendprop / /groups/uucp users <username>
   6. Check whether /var/lock exists
   7. if it doesn't exist then create it
      1. sudo mkdir /var/lock
5. You should reboot your computer to ensure that OSX has picked up all these changes

Inside: Apple serial cable

Outside: DE9 DCE loop back cable

Example programs can be found on the RXTX and Javax.com web sites. These can be used for loopback tests or as serial applications. Note: the use of import gnu.io.*; instead of //import javax.comm.*;

SerialDemo is a Java Swing application that displays a GUI to enable you to select a port and open it, and experiment with various port settings. It is set to no echo, so characters you type on the top pannel will appear on the bottom pannel when a loopback cable is connected. When connected to a serial device, it will support bi-directional interaction. An XCode project is available for download. (100kb .sitx) (.sitx files can be expanded with Stuffit expander from Allume Systems)

[Session started at 2006-07-18 10:05:24 +1000.]
Experimental: JNI_OnLoad called.
Stable Library
===============================
Native lib Version = RXTX-2.1-7
Java lib Version = RXTX-2.1-7
PORT NAME gnu.io.CommPortIdentifier@66afb3 /dev/tty.KeySerial1
RXTX Warning: Removing stale lock file. /var/lock/LK.003.009.002

[Session started at 2006-07-18 10:16:34 +1000.]
Experimental: JNI_OnLoad called.
Stable Library
===============================
Native lib Version = RXTX-2.1-7
Java lib Version = RXTX-2.1-7
/dev/tty.modem - Serial
/dev/cu.modem - Serial
/dev/tty.KeySerial1 - Serial
/dev/cu.KeySerial1 - Serial
/dev/tty.USA28X2b2P2.2 - Serial
/dev/cu.USA28X2b2P2.2 - Serial
6 ports found
Current owner is null
Name is TwoWaySerialComm
RXTX Warning: Removing stale lock file. /var/lock/LK.003.009.002
Serial port is /dev/tty.KeySerial1
keys typed on keyboard appear here (no loop back connector)

Cocoa Serial Programming

Macintosh wireless cable replacement

Probably uses a hardware line (DTR?) to switch to configuration mode so that it can use the serial line to talk to the Bluetooth card.

• DTE - computer, terminal
• DCE - Modem

Emulating an IBM PC Serial Port

• Computer - a DTE male socket
• Device - a DTE female plug

A Mac OSX driver can be downloaded

Programming is the same as for the Keyspan, except that the VISA serial close vi will cause a fail to open on subsequent runs, so it has to be removed.

Beware: these USB chips don't have serial numbers
(Keyspan do) so if you plug more than 1 into your
Mac it is very difficult to tell which is which in software.

Note: the Mac serial port (mini-DIN 8) is only ± 5volts while the PC (DE9) is ± 12 Volts

• This becomes a problem when the device is sourcing its power from the serial port

1. Cut an Apple serial cable in two
2. Wire a DE9 male connector to the end