The pocket A/D is an analog to digital converter, which is used to connect the printer port (centronics) of PC/AT, PC/386, PC/486, Pentium, or compatible computer. The pocket A/D is a high precision data conversion system, it contains eleven 12 ( or 10) bits analog to digital channels.
The pocket A/D does not need to occupy any slot of your PC system, it is suitable for any PC which contains a parallel printer port, especially, it is useful for laptops and notebooks.
There are two kinds of product, one is a pocket A/D box; and another is a pocket A/D prototype board which is used for laboratory purposes, many plated through-holes are located on the board.
The features of the pocket A/D are:
Support eleven 12 (or 10) bits channels.
Voltage range : 0 to 5V (or 0 to 10V).
Conversion time : 500 us.
Current consumption : 60 mA.
Linearity error : 1 LSB.
Power adapter : DC 9V, 500 mA.
Pocket A/D box or pocket A/D prototype board.
The package contains:
Pocket A/D.
Power adapter.
User's manual.
Expansion bus kit (optional).
Pocket A/D terminal board (optional).
Pocket ADDIO COM module (optional).
The dimension of pocket A/D box and pocket A/D prototype board are shown as below and on the following page.



Hardware Installation
Your pocket A/D is designed to be inserted in the parallel printer port of your computer, please follow the steps listed below.
1.
 Turn off all power to your computer and all peripheral devices before installing your pocket A/D.
2.
 Connect pocket A/D to printer port. (or connect expansion cable to printer port and expansion bus kit, then insert pocket A/D to the connector of expansion bus kit. Please see the expansion bus kit part of this manual).
3.
 Plug in power adapter to pocket A/D.
4.
 Turn on the computer and power adapter.


Hardware Configurations
Before you use the pocket A/D, you must ensure that the printer port address and identifier address are set correctly. The proper settings for the pocket A/D are described in the following.
I/O Port address
The A/D signals are transferred via parallel printer port, so that the I/O port address of pocket A/D is &H3BC, &H378, or &H278 depending on your printer port setting.
LED Indicator
The LED1 is used to indicate power active and LED2 is used to indicate signal access.
Identifier Address

The identifier address is used to identify the address of pocket A/D, user may use DIP switch to set identifier address, and each pocket A/D must be set to different identifier address. Observe figure above, to set the switch ON means 0 and set the switchOFF means 1. The figure above is set to 5.
Each expansion bus kit contains 6 connectors to connect maximum 5 pocket A/D or pocket DIO (you can mix it together).

Pin Assignment of Pocket A/D
Pin
 Function
 Pin
 Function
1
 GND
 14
 +5V
2
 CH0
 15
 GND
3
 CH1
 16
 GND
4
 CH2
 17
 GND
5
 CH3
 18
 GND
6
 CH4
 19
 GND
7
 CH5
 20
 GND
8
 CH6
 21
 GND
9
 CH7
 22
 GND
10
 CH8
 23
 GND
11
 CH9
 24
 GND
12
 CH10
 25
 +5V
13
 GND


Software Programming
In the distribution diskette, we provide C, PASCAL, ASSEMBLY, and BASIC examples to show how to write software to get A/D signals. It is easy to call the getad() function to get the converted digital signal from C and PASCAL. For BASIC language, the function is located at line number 1000.
1.
 Programming Guide

a.
 Initial


void adinit(unsigned int addr);
addr : printer port address.

b.
 Get A/D signal


int getad(int box, int channel);
box       : identifier address.
channel : A/D channel number.
return    : digital number.

c.
 Identify bits resolution


Modify RESOLUTION parameter, it will be 12 or 10.
2.
 Examples

On the next page, we show the flowchart to introduce how to program the software. The examples of C, PASCAL, BASIC, and ASSEMBLY are also shown in the following pages.

Notice
THIS IS IMPORTANT INFORMATION FOR POCKET ADDIO MODULES.
HARDWARE NOTICE:
1.
 IN THE POCKET A/D PRODUCT, THERE ARE LABELS ON EACH CONNECTOR, PLEASE FOLLOW THE DIRECTION OF LABEL NAME TO CONNECT THE CORRECT SIDE.
2.
 FIRST CONNECT THE POCKET A/D BOX, THEN SUPPLY THE POWER TO THE POCKET A/D BOX.
WARNING
DO NOT SUPPLY THE POWER FIRST, OTHERWISE IT WILL DAMAGE THE A/D CHIP.
SOFTWARE NOTICE:
IF YOU WISH TO USE A LONG CABLE MORE THAN 30CM. FOR THE POCKET A/D THROUGH THE PRINTER PORT, YOU NEED TO MAKE SOME CHANGES
IN THE SOURCE PROGRAM WHICH WE PROVIDE IN THE MANUAL (SEE CHAPTER 4). YOU NEED TO PROVIDE MORE DELAY IN UDELAY FUNCTION. (ALL UDELAY FUNCTION IN THE PROGRAM)
IN THE ORIGINAL PROGRAM (USING NORMAL CABLE)
outport (DATA(port_addr),x|CLK);
udelay (1);
REVISED PROGRAM (USING LONG CABLE)
outport (DATA(port_addr),x|CLK);
udelay (5);
WARNING
IF YOU USE MORE THAN 1 METER, YOU NEED TO ADD MORE DELAY.
GENERAL NOTICE:
1.
 PLEASE READ THE FILES READ.ME AND *.DOC IN THE DISTRIBUTION DISKETTE BEFORE YOU USE THE PACKAGE. ALL REVISED INFORMATION AND NEWS ARE STORED IN THOSE FILES.
2.
 IT PROVIDES MAXIMUM 16 POCKET A/D BOXES IN ONE SYSTEM WHEN YOU USE EXPANSION BUS KIT.
3.
 TO USE EXPANSION BUS KIT TO DRIVE MORE POCKET A/D BOXES, PLEASE USE SPECIAL POWER ADAPTER WHICH SUPPORTS 1000 mA.

Catalog
Manual
Schematic
Converter
Device Driver
Test Tool &
Sample Code
Measurement &
Applications