Sharp PC-E220 USB/Serial cable


Don't take care of the unuseful stuff at the top of the bread board  ... !

This page is made to explain how is it possible to link one's Sharp PC-E220 to a PC VIA an USB connector while this pocket computer was only made for Serial RS232 link !

Take into account the ready to use USB to PC-E220 cable from rh0d with his ebay account which could save you building and debugging time ... ! 

The Hardware

We must use a special interface cable made bay the FTDI society :the TTL-232R USB cable.
Its a cable that converts serial signals (with TTL levels) to USB ones and emulate a serial com port on the computer.
 The one I selected was the one with the 6 header interface (6 way, 0.1” pitch). It provides classical RS232 signal AND a power pin (5V).

All what is needed is to the cable pins with the appropriate ones on the PC-E220 interface connector.

Available cable signals :   Sharp PC-E220 side connector

According to this web page.here is the description of the PC-E220 connectors pin (from left to right):
[ 1] Buzzer
[ 2] VCC (+6v)
[ 3] GND
[ 4] RTS
[ 5] Dout        (?)
[ 6] RXD
[ 7] TXD
[ 8] Din          (?)
[ 9] CTS
[10] not connected
[11] not connected

And here is the appropriate wiring (the one that works for me). WARNING : take care : you may destroy your calculator with a wrong wiring !


CABLE END    to       Sharp PC-E220
[1] GND ---------------> GNG [3]
[2] CTS # ---- (not used)
[3] VCC  ---- (not used)
[4] TXD  ----------------- RXD [6]
[5] RXD -----------------  TXD [7]
[6] RTS # ----------------  CTS [9]

The Software

The TTL-232R cable can be configured with the appropriate software (FT-PROG from FTDI).
The only configuration needed is to invert the signal level of all cable pins. Check in FT-PROG that all signal are inverted and appropriate box checked. Then apply configuration on the cable.
WARNING : After programmation, UNPLUG then RE-plug the cable otherwise, it will keep it's initial configuration !


Then, you can use Hyperterminal to send and receive ASCII programs to and from the PC-E220.

Take care when using Hyperterminal of the following things:
  • Open communication otherwise nothing will be sent/received !
  • Check that Computer and PC-E220 transmission parameters match !
  • Use "Capture text file" and "Send Text file" features.

The Sharp PC-E220 software

Before saving programs, the principle of file management of the PC-E220 must be explained.

How to SAVE a BASIC program file ?

The objective is to convert the BASIC file into the ASCII Text Editor, adjust the Serial Parameters and then send the file.
  • Enter TEXT area by pressing  + button :
  • Check EDITOR contains by pressing [E] key then the DOWN arrow :
    Press [ON/BREAK] key to return to global TEXT EDITOR screen.
  • Delete any previous text in the EDITOR area by pressing [D] key,
    then confirm by [Y] :
  • Access to the BASIC <=> TEXT converter by pressing [B] Key
  • Convert BASIC program into TEXT by pressing [T] key,
    then confirm by [Y] :
  • Access to the SERIAL Input Ouput menu by pressing [S] key :
  • Access to SERIAL parameters zone by pressing [F] key,
    - Select and adjust the parameter with the arrow key,
    - Return to the S.I.O. main menu (ON/BREAK key).
  • Send the ASCII file by pressing the [S] key,
    - Return to the S.I.O. main menu (ON/BREAK key).

How to LOAD a BASIC program file ?

The objective is to adjust the Serial Parameters, load the ASCII file from the PC to the Text Editor Memory then convert the ASCII file into the BASIC Program Memory.
  • Enter TEXT area by pressing  + button :
  • Access to the SERIAL Input Ouput menu by pressing [S] key :
  • Access to SERIAL parameters zone by pressing [F] key,
    - Select and adjust the parameter with the arrow key,
    - Return to the S.I.O. main menu (ON/BREAK key).
  • (not mandatory, just for information ...)
    Delete any previous text in the EDITOR area by pressing [D] key,
    then confirm by [Y] :
  • Load the ASCII file by pressing the [L] key,
    - Send the file via the computer ...
    - Return to the S.I.O. main menu (ON/BREAK key).
    - Return to the TEXT area by pressing the ON/BREAK key.
  • Access to the BASIC <=> TEXT converter by pressing [B] Key
  • Convert ASCII TEXT file into BASIC program by pressing [B] key,
    then confirm by [Y] 

    - The BASIC file is ready for running or editing (press the BASIC key)

 An overview of the main menu of the Sharp PC-E220 is available as a big image for better understanding :