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Sharp Pocket Computer Resources
Sharp Pocket Computer - Serial Interface
Universal Serial Interface for Sharp Pocket Computers

Universal Serial Interface for Sharp Pocket Computers

Introduction

First a warning:

Building and using this interface is on your own risk, there is no warranty of any kind.

And now, lets start:

This article enables you to construct a serial interface for all sharp computers with the 11 pin peripheral interface or the 15 pin serial interface. The interface performs a level conversion any has various jumpers to configure it for the use with your pocket computer and transmission software. The purpose of the device is to link your pocket computer to the serial port of your personal computer. There are different software products you can use on the personal computer side:

Standard Terminal Program

Terminals like Teraterm, Minicom, Seyon and Hyperterminal may be used for all pockets with the 15 pin serial interface (PC-1350, PC-1360, PC-E500(S) ...). Just set the com parameters to the same values on the pocket and on the PC. The programs are transferred in ASCII format. When downloading files to the pocket, you usually have to type a Ctrl-Z after end of transmission to get the basic prompt again.

Beside this, there are many transfer programs for the serial ASCII transfer over the 15 pin peripheral interface, e.g. from Simon Lehmayr.

The PC-E220 is also able to work with a Standard Terminal Program, but this model has it's serial interface integrated into the 11 pin peripheral port. The power supply may be remote controlled from pin 5 of the peripheral interface, so you don't need to use a power switch for the universal serial interface circuit. I think, the PC-E220 has the best serial interface, because

  • it uses a simple 2,54 mm pinhead
  • the big AA-batteries of the pocket may be used for the interface supply too
  • the supply may be remote controlled.
The PC-1403(H) is able to to work with a standard terminal program if a driver (machine language) is installed into the pocket. There are two drivers available for the PC-1403(H):
  • PETOOLS 1.1 has a integrated serial port driver (will be released soon on this site)
  • The was an article in the C'T magazine (Go to www.heise.de and search the article archive for C'T 1989, number 3. The title (in german) is "Tore zur Welt"). The [BROKEN] SHARP Pocketcomputer Seite von Jerry C has also published a page that with a home made serial interface based on this article.
On a PC-1403(H) with PETOOLS 1.1 (or higher), the programs are transferred in ASCII mode, but you need a (de)tokenizer on the host PC to convert the basic tokens to/from ASCII. Maybe I'll publish one with PETOOLS 1.1. If you use the software published in C'T, you don't need a (de)tokenizer, but this software can't handle some basic commands like "XOR". The software from C'T is also available for the PC-1401/1402, but I didn't check this out.

The advantage of using a standard terminal is that it is platform independent, the files are transferred in ASCII mode and you don't need to switch to DOS mode. The transfer rate is up to 9600 bd (CLOAD/CSAVE: less than 500 bd).

FAZ' Software

This software is available from [BROKEN] FAZ'homepage. It emulates a tape drive, you can use CLOAD, CSAVE and MERGE (and maybe INPUT# and PRINT#).Should work for all pockets except the PC-Exxx series. You may backup the content of your pocket with it, but there is no converter to/from ASCII format. Should run in DOS mode, source code is included.

Friedi's Software

Available from [BROKEN] SHARP PC-1403(H) Resourcen, runs in DOS mode. Also emulates a tape drive, you can use CLOAD, CSAVE and MERGE. The models PC-1251, PC-1262 and PC-1403(H) are supported. A (de)tokenizer is included. There is a sharp printer emulation included, it worked for LPRINT and P <-> NP, but not for LLIST. To have a better screen layout, just type the following before starting Friedi's software:

mode con codepage prepare=((437) C:\WINDOWS\COMMAND\ega.cpi)
mode con codepage select=437

Hardware

The hardware consists of the interface board, cable A for all pockets with the 11 pin peripheral interface and cable B for all pockets with the 15 pin serial interface. The pins of the pockets are numbered as follows (e.g. PC-1360):

    +-------------------------------------------------------------------------+ 
    |            PC-1360                                                      | 
 1 -+                                                                         +-  1 
 2 -+                                                                         +-  2 
 3 -+                                                                         +-  3 
 4 -+                                                                         +-  4 
 5 -+                                                                         +-  5 
 6 -+                                                                         +-  6 
 7 -+                                                                         +-  7 
 8 -+                                                                         +-  8 
 9 -+                                                                         +-  9 
10 -+                                                                         +- 10 
11 -+                                                                         +- 11 
    |                                                                         +- 12 
    |                                                                         +- 13 
    |                                                                         +- 14 
    |                                                                         +- 15 
    |                                                                         | 
    +-------------------------------------------------------------------------+ 

Pin Assignment between Cable A, Cable B and the 2 x 5 Pinhead of the interface board

2 x 5 pinhead Cable A (11 pin) Cable B (15 pin)
1 2 10
2 3 7
3 4 11
4 5 -
5 6 3
6 7 2
7 8 -
8 9 5
9 10 -
10 11 -

Pin 8 and pin 14 of the 1,27 mm pinhead (15 pin) of cable B are connected together. 1,27 mm pinheads are available at e.g. at Conrad electronic. If you want to use the internal batteries of the pocket, you can mount a switch between pin 1 of the 2 x 5 pinhead and pin 10 of the pinhead of Cable B (15 pin). With Cable A, this wouldn't make sense, because the widely used CR-2032 batteries would be discharged very fast and the PC-E220 (which has AA-batteries) is able to remote control the power supply.

The Interface Board

Click to get high resolution picture

Yep, that's it. The parts should be available in every electronic store. All resistors are 1/8 Watt, all electrolytic capacitors are specified with 16V. If you want to use a external battery, connect it between "BATT" (plus pole) and "GND" (minus pole). If you want to use a DC adapter, connect it between pin "DC-ADAP" and "GND". A 9V block would be suitable (put a power switch between the plus pole of the battery and "BATT"). The 78L06 create a stable voltage of 6V. T1 reduces this voltage to an amount of 5V, it may be remote controlled from pin 4 (= pin 5 on cable A). LED D8 is on if the circuit is supplied from a DC adapter. If you use a battery, you can solder a test button between pin "BATT" and "TEST". If it's pressed the LED emits light.

For the first tests, I would do the following:

  • Use sockets for IC1 and IC2
  • Build up the circuit, but don't insert IC1 and IC2 and don't connect a pocket or the PC
  • Connect a supply (DC adapter or ext. battery)
  • Check if JP1, pin 1 has 6V to GND (use a voltmeter)
  • Set a bridge JP1, pins 1&2 and JP2, pins 1&2
  • Now check the voltage on the sockets of IC1 and IC2 (IC1: 5V between pins 7&14, 14 is plus; IC2: 5V between pins 15 and 16, 16 is plus) The voltage may be slightly over 5V, because the is no load and C5 may be loaded over 5V, but that is no problem
  • Now turn of the power, insert the integrated circuits and turn the power on
  • Check the voltage on pin 2 of IC2 (about 10V to GND) and pin 6 of IC2 (about -10V to GND)
  • Turn off the power, set the jumpers right for your needs, connect cable A or B, the pocket and the PC and turn the power on again.
  • Ready to go!

Cable A

Use a Plug suitable for the 2 x 5 pinheads, a ribbon cable a 2,54 mm pinhead (11 pin). For my prototype, I used a small piece of experimental PCB to connect the ribbon cable and the pinhead JP1. It is also possible to create a small adapter PCB.

Cable B

That's it. All wrote about cable A is also valid here (but you need a 1,27 mm pinhead), and note the remarks made in the section Pin Assignment between Cable A, Cable B and the 2 x 5 Pinhead of the interface board. Phew, the small pinhead is very tricky to solder at a ribbon cable!

PCB Developers Resources

If you want to create a PCB ... just do it, an send a mail with the result to me :-) Here are the schematics. They were drawn with Eagle 4.08r2, the electrical rule check gives only one warning for the not connected pin 6 of IC1, so the creation of a PCB shouldn't be a big problem. A light version (free for private use) is available from www.cadsoft.de.

Description of the Jumpers

All pin numbers refer to the 11 pin peripheral interface, if you want to know the pin numbers on cable B or the 2 x 5 pinhead, refer to Pin Assignment between Cable A, Cable B and the 2 x 5 Pinhead of the interface board. To get the pin numbers to the serial port signal names, just look somewhere else on the net, e.g. [BROKEN] SHARP PC-1403(H) Resourcen has a description of the serial port pins.
Jumper Description Possible settings
JP1 Power supply 1-2 extern battery
2-3 internal battery of the pocket
JP2 Operate 1-2 always
2-3 remote controlled from pin 5 (for PC-E220)
JP3 Pin 4 & 7 configuration 1-3, 2-4 Pin 4 = CTS, Pin 7 = RXD/RI
1-2, 3-4 Pin 4 = RXD/RI, Pin 7 = CTS
1-3 Pin 4 n.c., Pin 7 RXD/RI
2-4 Pin 4 CTS, Pin 7 = n.c.
JP4 Pin 6 & 9 configuration 1-2, 3-4 Pin 6 = TXD, Pin 9 = RTS/DTR
2-3 Pin 6 RTS/DTR, Pin 9 = n.c.
3-4 Pin 6 TXD, Pin 9 = n.c.
JP5 Pin 8 configuration closed Pin 8 = inverted TXD
open Pin 8 = n.c.
JP6 Pin 10 configuration closed Pin 7 - Pin 10 loop back
open Pin 10 = n.c.
JP7 RI/RXD preselect 1-2 RI preselected
2-3 RXD preselected
JP8 DCD function 1-2 DCD = Pin 5
2-3 DCD - DTR loop back
open DCD = n.c.
JP9 DSR configuration closed DSR - DTR loop back
open DSR = n.c.
JP10 RTS/DTR preselect 1-2 DTR preselected
2-3 RTS preselected

Operating the Interface

To connect the interface to your PC, you need a serial cable. One plug is female and has 9 pins, the other is male and has also 9 pins. They are connected 1:1. Such a cable is available in most computer shops for about 3 EUR (bucks?).

Jumper Settings for the universal serial Interface for Sharp Pocket Computers

Power supply JP1
External 1-2
Internal from pocket computer 1) 2-3

Pocket Computer Cable Software JP2 JP3 JP4 JP5 JP6 JP7 JP8 JP9 JP10
PC-E220 A Standard terminal 2-32) 1-3, 2-4 1-2, 3-4 open open 2-3 open closed 2-3
PC-1251, PC-1262, PC-1403(H) A Friedi's Software 1-2 1-3, 2-4 1-2, 3-4 open closed 1-2 1-2 open 2-3
Most pockets except PC-Exxx A FAZ' Software 1-2 1-3 3-4 open open 2-3 open open open
PC-1403(H) A Standard terminal + PETOOLS 1.13) 1-2 1-2, 3-4 2-3 closed open 2-3 2-3 closed 1-2
PC-1350, PC-1360, PC-E500(S)4) B Standard terminal 1-2 1-3, 2-4 1-2, 3-4 open open 2-3 open closed 2-3
PC-1401, PC-14025) A Standard terminal + Software from C'T (www.heise.de) 1-2 1-2, 3-4 2-3 closed open 2-3 2-3 closed 1-2

Now have fun with your interface!



1) Only recommended for models which have AA or AAA batteries (no lithium button cells), e.g. PC-E220 and PC-E500(S)
2) The PC-E220 model turns the supply of the interface on or off by using pin 5 of the 11 pin interface, if JP2 is set to 2-3
3) or higher, ore use the software published in C'T (www.heise.de)
4) or other pockets with 15 pin serial interface
5) I have not tested it with the PC-1402 until now
Edgar Pühringer
last modified: 2009-10-14