Omega Vehicle Security Network Card DAQ 16 User Manual

DAQ-16  
Data Acquisition Adapter  
for 16-bit ISA compatible machines  
Users Manual  
INTERFACE CARDS FOR PERSONAL COMPUTERS  
OMEGA ENGINEERING, INC.  
One Omega Drive  
P.O. Box 4047  
Stamford, CT 06907-4047  
TEL: (203) 359-1660  
FAX: (203) 359-7700  
Toll free: 1-800-826-6342  
 
OMEGAnet On-line Service:  
Internet e-mail:  
info@omega.com  
Servicing North America:  
USA:  
ISO 9001 Certified  
One Omega Drive, Box 4047  
Stamford, CT 06907-0047  
Tel: (203) 359-1660  
E-mail: info@omega.com  
FAX: (203) 359-7700  
Canada:  
976 Bergar  
Laval (Quebec) H7L 5A1  
Tel: (514) 856-6928  
E-mail: info@omega.com  
FAX: (514) 856-6886  
For immediate technical or application assistance:  
USA and Canada:  
Sales Service: 1-800-826-6342 / 1-800-TC-OMEGASM  
Customer Service: 1-800-622-2378/ 1-800-622-BESTSM  
Engineering Service: 1-800-872-9436 / 1-800-USA-WHEN SM  
TELEX: 996404 EASYLINK: 62968934 CABLE: OMEGA  
Mexico and Latin America: Tel: (001) 800-826-6342  
En Espanol: (001) 203-359-7803  
FAX: (001) 203-359-7807  
E-mail: espanol@omega.com  
Servicing Europe:  
Benelux:  
Postbus 8034, 1180 LA Amstelveen, The Netherlands  
Tel: (31) 20 6418405  
Toll Free in Benelux: 0800 0993344  
E-mail: nl@omega.com  
Czech Republic:  
ul.Rude armady 1868, 733 01 Karvina-Hraniee  
Tel: 42 (69) 6311899  
FAX: 42 (69) 6311114  
Toll Free: 0800-1-66342  
E-mail: czech@omega.com  
France:  
9, rue Denis Papin, 78190 Trappes  
Tel: (33) 130-621-400  
Toll Free in France: 0800-4-06342  
E-mail: france@omega.com  
Germany/Austria:  
Daimlerstrasse 26, D-75392 Deckenpfronn, Germany  
Tel: 49 (07056) 3017  
Toll Free in Germany: 0130 11 21 66  
E-mail: germany@omega.com  
DAQ-16 Users Manual  
3
 
United Kingdom:  
ISO 9002 Certified  
One Omega Drive, River Bend Technology Drive  
Northbank, Irlam, Manchester  
M44 5EX, England  
Tel: 44 (161) 777-6611  
FAX: 44 (161) 777-6622  
Toll Free in England: 0800-488-488  
E-mail: info@omega.co.uk  
It is the policy of OMEGA to comply with all worldwide safety and EMC/ EMI regulations that apply.  
OMEGA is constantly pursuing certification of its products to the European New Approach  
Directives. OMEGA will add the CE mark to every appropriate device upon certification.  
The information contained in this document is believed to be correct but OMEGA Engineering, Inc.  
accepts no liability for any errors it contains, and reserves the right to alter specifications without  
notice. WARNING: These products are not designed for use in, and should not be used for, patient  
connected applications.  
DAQ-16 Users Manual  
4
 
Declaration of Conformity  
Manufacturer's Name:  
Omega Engineering Inc.  
Manufacturer's Address:  
One Omega Drive  
Stamford, CT 06907-0047  
Application of Council Directive:  
89/ 336/ EEC  
Standards to which  
Conformity is Declared:  
* EN50081-2  
(EN55022, EN60555-2, EN60555-3)  
* EN50082-1  
(IEC 801-2, IEC 801-3, & IEC 801-4)  
Type of Equipment:  
Equipment Class:  
Product Name:  
Information Technology Equipment  
Light Industrial Equipment  
ISA Data Acquisition Card  
DAQ-16  
Model Number :  
DAQ-16 Users Manual  
5
 
Table of Contents  
1. Introduction  
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8  
1.1 Installation  
1.2 DAQ-16 Specifications  
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9  
2. Circuit Board Description and Configuration  
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10  
2.1 Analog to Digital Converter  
2.2 Digital to Analog Converters  
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14  
2.3 Digital Input/ Output  
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15  
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16  
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17  
2.4 Base Address  
2.5 Clock Selection  
2.5.1 Internal Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18  
2.5.2 External Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19  
2.6 Trigger Selection  
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20  
2.7 Direct Memory Access  
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21  
2.8 Interrupts  
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22  
2.8.1 External Interrupt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22  
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23  
4. Register Description and Programming  
. . . . . . . . . . . . . . . . . . . . . 25  
4.1.1 Control Word Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25  
4.1.2 Start of Conversion Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27  
4.1.3 DAC0 Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27  
4.1.4 DAC1 Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27  
4.1.5 Clock Rate Register (low word) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27  
4.1.6 Clock Rate Register (high word) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27  
4.1.7 Multi-Function Timer Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27  
4.1.8 8254 Control Word/ Status Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27  
4.2 Programming the 8254 Counter/ Timer  
. . . . . . . . . . . . . . . . . . . . . . . . . . . . 28  
DAQ-16 Users Manual  
6
 
List of Figures and Tables  
Figure 2-1. Jumper J7 Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11  
Figure 2-2. Jumper J6 Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11  
Figure 2-3. Jumper J5 Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12  
Figure 2-4. Jumper J3 Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14  
Figure 2-5. I/ O Base Address Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16  
Figure 2-6. Jumper J2 Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17  
Figure 2-7. Sampling Rate External Clock Pulses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19  
Figure 2-8. Pre-Divider External Clock Pulses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20  
Figure 2-9. Jumper J1 Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20  
Figure 2-10. Jumpers J8 and J9 Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21  
Figure 2-11. Jumpers J10 and J11 Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22  
Figure 3-1. 62 Pin Connector Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23  
Table 2-1.  
Table 2-2.  
Table 2-3.  
Table 4-1.  
A/ D Converter Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10  
A/ D Conversion Format Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13  
Jumper J4 Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15  
DAQ-16 Address Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25  
DAQ-16 Users Manual  
7
 
1. Introduction  
The DAQ-16 is a high speed data acquisition adapter for IBM AT compatible machines  
offering eight differential analog input channels with 16-bit resolution, two analog output  
channels with 12-bit resolution and four digital input/ output lines. Other features of the  
DAQ-16 include:  
Analog to Digital Converter  
100 KHz maximum sampling rate  
Bipolar input ranges of ±2.5, ±5, and ±10 volts  
Unipolar input ranges of 0 to +2.5, 0 to +5 and 0 to +10 volts  
Selectable gain of 1, 10, and 100  
Two DMA channels for continuous acquisition  
Internal or external clock and trigger  
Digital to Analog Converters  
Two independent analog output channels  
Output ranges of 0 to +5 volts and ±5 volts  
Internal or external voltage reference  
Other Features  
Interrupt on one of four sources including an external interrupt input  
High density D-62 connector for reduced noise  
1.1  
Installation  
1. Configure the DAQ-16 utilizing the instructions in Chapter 2: Circuit Board  
Description and Configuration.  
2. Ensure that power is not applied to the computer system.  
3. Remove the cover according to the instructions provided by the system  
manufacturer.  
4. Insert the DAC-16 into any vacant ISA expansion slot. The board is secured to the  
slot by installing the Option Retaining Bracket (ORB) screw.  
5. Replace the system cover per manufacturer instructions.  
DAQ-16 Users Manual  
8
 
 
1.2  
DAQ-16 Specifications  
Bus Interface:  
ISA 16-bit  
I/ O Address Range:  
Interrupt Levels:  
DMA Levels:  
0000H - FFFFH  
IRQ 2, 3, 4. 5, 6, 7, 10, 11, 12, 14, 15  
DRQ 5, 6, 7  
DACK 5, 6, 7  
Power Requirements:  
Power Supply  
-5 volts  
I(t)  
---  
I(ms)  
---  
+5 volts  
1069.0 mA  
---  
1204.9mA  
---  
-12 volts  
+12 volts  
374.9 mA  
491.4mA  
I(t) = Typical Current / I(ms) = Maximum Statisical Current  
DAQ-16 Users Manual  
9
 
2. Circuit Board Description and Configuration  
The base address of the DAQ-16 is selected using switches SW1 and SW2. The operating  
mode of the DAQ-16 is controlled by jumpers J1 through J7, while DMA and interrupt  
selections are set with jumpers J8 through J11. Connections to external equipment are made  
through the high density 62-pin connector CN1.  
2.1  
Analog to Digital Converter  
The analog to digital (A/ D) section of the DAQ-16 accepts up to 8 differential inputs from the  
D-62 connector. These inputs pass through a dual 8-to-1 multiplexer circuit which selects the  
channel to be converted. The selected input is then amplified and presented to the A/ D  
converter to be digitized. The digital output of the A/ D is latched into a buffer to be read by  
the computer. The multiplexer circuit selects one of the 8 differential channels to be input to  
the A/ D converter. The channel is software selected through the DAQ-16's control word  
register. The typical characteristics of the multiplexer circuit are:  
input resistance: 1.5 Kohm  
switching time: 0.5 us  
settling time: 3.5 us  
The amplifier stage of the A/ D converter circuit performs two functions: (1) amplifies low  
level input signals and (2) converts this input signal into a voltage range acceptable to the  
A/ D converter. The amplifier circuit is controlled by jumpers J6 and J7. Table 2-1 below  
shows the recommended jumper settings for various input voltage ranges, (* indicates factory  
settings).  
Maximum Input Voltage  
Unipolar / Bipolar  
+10/ ±10  
Amplifier  
A/D Range  
---  
J7  
---  
J6  
---  
1
---  
3-4*  
3-4  
3-4  
2-4  
2-4  
2-4  
1-3  
1-3  
1-3  
10 v  
5 v  
2-3, 5-6*  
1-2, 4-5  
2-3, 4-5  
2-3, 5-6  
1-2, 4-5  
2-3, 4-5  
2-3, 5-6  
1-2, 4-5  
2-3, 4-5  
+5/ ±5  
1
+2.5/ ±2.5  
1
2.5 v  
10 v  
5 v  
+1/ ±1  
10  
10  
10  
100  
100  
100  
+0.5/ ±0.5  
+0.25/ ±0.25  
+0.1/ ±.1  
2.5v  
10 v  
5 v  
+0.05/ ±0.05  
+0.025/ ±0.025  
2.5 v  
Table 2-1. A/ D Converter Configurations  
DAQ-16 Users Manual  
10  
 
 
Figures 2-1 and 2-2 show the configuration options for jumpers J7 and J6.  
J7  
J7  
J7  
3
1
3
1
4
2
4
2
4
2
3
1
Gain = 1  
Gain = 10  
Gain = 100  
Figure 2-1. Jumper J7 Configuration  
J6  
J6  
5
J6  
5
4
1
5
6
3
4
1
6
3
4
1
6
3
2
2
2
2.5 volt range  
5 volt range  
10 volt range  
Figure 2-2. Jumper J6 Configuration  
WARNING: These settings are only suggestions, it is the user's responsibility to guarantee  
that the maximum input voltage multiplied by the gain setting selected by jumper J7 does  
not exceed the A/ D voltage range set by jumper J6.  
DAQ-16 Users Manual  
11  
 
The final stage of the A/ D converter circuit is the A/ D converter IC. The converter must be  
configured for unipolar or bipolar input voltages and for binary or 2's complement data  
conversion. These options are selected using jumper J5 as shown in Figure 2-3 below.  
J5  
5
J5  
5
4
6
4
6
1
4
2
3
1
2
3
Bipolar  
Unipolar  
J5  
J5  
5
6
4
5
6
1
2
3
1
2
3
2's complement  
Binary  
Figure 2-3. Jumper J5 Configuration  
To simplify the following discussions, a new variable, Vmax, is introduced. Vmax is defined  
as the maximum input voltage amplitude and is equal to the A/ D range selected by jumper J6  
divided by the amplifier gain defined by jumper J7. In equation form:  
A/ D range  
Vmax =  
---------------  
amp. gain  
When configured for unipolar operation, the input voltage may range from 0 volts (analog  
ground) to Vmax volts as defined above. When configured for bipolar operation, the input  
voltage may range from -Vmax volts to +Vmax volts.  
The digital "code" generated for any specific voltage is dependent upon the operating mode:  
unipolar or bipolar; and the data conversion format: binary or 2's complement. Binary  
conversion will result in unsigned integers ranging from 0 to 65,535, while 2's complement  
conversion will produce signed integers ranging from -32,768 to +32,767. Table 2-2 lists A/ D  
conversion format examples. Unipolar entries marked “n/ a” are not applicable because the  
voltage is outside of the unipolar voltage range.  
DAQ-16 Users Manual  
12  
 
Voltage  
Binary  
Binary 2s Complement 2s Complement  
unipolar bipolar  
unipolar  
n/ a  
n/ a  
-32,768  
0
bipolar  
-32,768  
-16,384  
0
+16,384  
+32,767  
-Vmax  
-Vmax/ 2  
0
+Vmax/ 2  
+Vmax  
n/ a  
n/ a  
0
+16,384  
+32,768  
+49,152  
+65,535  
0
+32,768  
+65,535  
+32,767  
Table 2-2. A/ D Conversion Format Examples  
In order to calculate the actual input voltage from the digital "code" provided by the DAQ-16,  
the user must know the configuration used to acquire the data. Given this information, the  
input voltage can be calculated using the equations below:  
Unipolar, binary  
CODE  
65, 536  
input =  
* Vmax  
Bipolar, binary  
CODE  
65, 536  
1
2
input =  
-
* 2 * Vmax  
Unipolar, 2s complement  
input =  
Bipolar, 2s complement  
input =  
CODE  
1
2
+
* Vmax  
65, 536  
CODE  
65, 536  
* 2 * Vmax  
DAQ-16 Users Manual  
13  
 
2.2  
Digital to Analog Converters  
The digital to analog (D/ A) section of the DAQ-16 consists of two independent 12-bit  
multiplying D/ A converters, and two independent two-stage output amplifiers. Digital data,  
(output to the D/ A converter by the CPU), is converted to an analog voltage by the D/ A  
converter, amplified by the output amplifiers and becomes output to the 62 pin connector at  
CN1. The D/ A converters used on the DAQ-16 are 12-bit resolution converters. Of the 16 bits  
written to the D/ A, only the 12 least significant bits (D0 - D11) are used for the conversion.  
The 4 most significant bits (D12 - D15) are ignored.  
The DAQ-16 implements multiplying D/ A converters which makes the analog output  
proportional to a reference voltage applied to the D/ A. Under normal circumstances, the  
reference voltage should be applied from the internal +5V reference source. An external  
reference voltage may also be supplied to the D/ A. This input from the D-62 connector should  
not exceed 5 volts and has a typical input impedance of 7.5Kohms. The D/ A reference voltage  
source is selected using jumper J3 as illustrated in Figure 2-4.  
D/A channel 0 reference  
Internal Source  
J3  
External Source  
External Source  
4
5
6
1
2
3
Internal Source  
D/A channel 1 reference  
Figure 2-4. Jumper J3 Configuration  
The D/ A converter channels may also be operated in unipolar mode: 0 to +5 volts, or bipolar  
mode: -5 to +5 volts. The output mode is selected using jumper J4 as shown in Figure 2-5. In  
addition, a gain selection jumper is provided to select an output gain of 1 or 2. When using  
an external voltage reference, this gain can be used to amplify the D/ A output for small  
reference voltages.  
WARNING: When the internal voltage reference is used, the D/ A gain MUST be set to the  
gain = 1 position.  
DAQ-16 Users Manual  
14  
 
5
1
6
2
7
3
8
4
J4  
Channel 0 select  
Channel 0 gain  
Channel 1 gain  
Channel 1 select  
Figure 2-5. Jumper J4 Configuration  
Table 2-3 lists configuration options for jumper J4.  
Channel 0  
connect 1-5  
open 1-5  
connect 2-6  
open 2-6  
Channel 1  
connect 3-7  
open 3-7  
connect 4-8  
open 4-8  
Bipolar  
Unipolar  
Gain = 1  
Gain = 2  
Table 2-3. Jumper J4 Configuration  
When configured for unipolar operation, the output voltage can be calculated from the  
equation:  
CODE  
4096  
Aout = Vref  
*
* gain  
For bipolar operation, the equation becomes:  
CODE  
2048  
Aout  
=
- 1 * Vref * gain  
2.3  
Digital Input/Output  
The DAQ-16 offers four bits of digital output and four bits of digital input for  
control/ monitoring of external digital devices. The four digital output lines are LS TTL  
compatible and will initialize low (0 volts) on power-up. The four digital inputs are also LS  
TTL compatible. There is no termination provided on the digital input lines and a read of an  
unused digital input will result in an indeterminate value.  
DAQ-16 Users Manual  
15  
 
2.4  
Base Address  
The DAQ-16 uses 16 consecutive I/ O address locations in the range 0 to 0FFFFH. Two  
six-position switches (SW1 and SW2) are used to select the base address. SW1 controls  
address lines A15 - A10, and SW2 controls A9 - A4. Address lines A3 - A0 are used  
internally by the DAQ-16 to select which register to access.  
When selecting a base address for the DAQ-16, an address selection switch in the "OFF"  
position corresponds to an address bit of "1" while a switch in the "ON" position corresponds  
to an address bit of "0". The base address of the DAQ-16 must be set on a 16 byte boundary,  
meaning A3 - A0 are "0". The address of the DAQ-16 as shipped from the factory is 0300H.  
This setting and other examples are shown in the Figure 2-5.  
xxxx Hex  
x x x x x  
x x x x x x  
x
0000  
SW1  
1
2
3
4
5
6
1
2
3
4
5
6
0000 : 0  
O
N
O
N
0001 : 1  
0010 : 2  
0011 : 3  
0100 : 4  
0101 : 5  
0110 : 6  
0111 : 7  
1000 : 8  
1001 : 9  
1010 : A  
1011 : B  
1100 : C  
1101 : D  
1110 : E  
1111 : F  
Bit=0 Bit=1  
SW2  
A A A A A A  
15 14 13 12 11 10  
A A A A A A  
8 7  
9
6
5
4
0
3
0
0
0
0 0 0 0 0 0  
1 1 0 0 0 0  
1
2
3
4
5
6
1
2
3
4
5
6
O
N
O
N
Example1: Base I/O Address = 0300H  
A
6
D
0 1 1 0 1 0  
1 0 1 1 0 1  
1
2
3
4
5
6
1
2
3
4
5
6
O
N
O
N
Example 2: Base I/O Address = 6AD0H  
Figure 2-5. I/ O Base Address Selection  
DAQ-16 Users Manual  
16  
 
2.5  
Clock Selection  
The DAQ-16 is equipped with a programmable clock circuit to produce data sampling rates  
independent from the clock rate of the host computer. An onboard 8254 programmable  
interval timer, with a 10 MHz clock input and either two or three cascaded 16-bit timers,  
provides the sampling rate. This enables the sampling rate to be adjusted from 10 us between  
samples to almost a year between samples, in as small as 100ns increments.  
The DAQ-16's sampling rate can also be generated from an external clock input. This external  
clock can be connected directly to the A/ D converter or through a 16-bit pre-divider, the  
multi-function timer. Samples are taken on the low to high transition of the clock.  
WARNING: For the DAQ-16, the maximum data sampling rate is 10 us. This restricts  
clock frequency to a maximum of 100 KHz. Sampling rates in excess of 100 KHz may  
result in erratic operation and unpredictable results.  
The clock source, internal or external clock, is software selectable through the DAQ-16's  
control word register. The configuration of the clock source itself is controlled by jumper  
block J2 as shown in Figure 2-6, (* indicates factory default).  
Internal Timer: 2 timers cascaded  
connect 1-2, 6-7*  
J2  
3 timers cascaded  
connect 2-6, 7-8  
5
1
6
7
3
8
4
External Timer: w/o pre-divider  
connect 1-2, 3-4  
2
with pre-divider  
connect 2-3, 4-8  
Figure 2-6. Jumper J2 Configuration  
DAQ-16 Users Manual  
17  
 
2.5.1  
Internal Clock  
Sampling rates for the internal clock can be calculated using the following equation:  
t = 100ns * [N1*N2] or  
f = 10MHz / [N1*N2]  
where N1 is the low 16-bits of the clock divider and N2 is the high 16-bits of the clock  
divider. The following criteria must be met when selecting values for N1 and N2:  
2 < N1 < 65,535  
2 < N2 < 65,535  
N1 * N2 > 100  
Using the equations above, the minimum and maximum data sampling rates for the internal  
clock can be calculated.  
Maximum sampling rate:  
N1 = 2, N2 = 50  
Minimum Sampling Rate:  
N1 = 65535, N2 = 65535  
t = 100 x 109 * [(2)*(50)]  
t = 100 x 109 * 100  
t = 10 us  
t = 100 x 109 * [(65535)*(65535)]  
t = 100 x 109 * [4.295 x 109 ]  
t = 429.5 sec  
f = 10 x 106 / [(2)*(50)]  
f = 10 x 106 / 100  
f = 100 Khz  
f = 10 x 106/ [(65535)*(65535)]  
f = 10 x 106 / [4.295 x 109 ]  
f = 2.328 mHz  
If extremely slow data sampling rates are needed, the third 8254 timer, the multi-function  
timer, can be cascaded with the other two to produce a 48-bit clock divider. The sampling  
rates are then calculated as follows:  
t = 100ns * [N1*N2*N3] or  
f = 10MHz / [N1*N2*N3]  
where N1 is the low 16-bits of the clock divider, N2 is the intermediate 16-bits of the clock  
divider, and N3 is the high 16-bits of the divider. The following criteria must be met when  
selecting values for N1, N2, and N3:  
2 < N1 < 65,535  
2 < N2 < 65,535  
2 < N3 < 65,535  
N1 * N2 * N3 > 100  
DAQ-16 Users Manual  
18  
 
When configured for a 48-bit divider, the first sampling period will be slightly longer than  
the others because the first clock period is required to load the initial value of the  
multi-function timer. The following equation calculates the additional time of the first period:  
tadd = 100ns * [N1 * N2]  
To minimize the amount of additional time required for the first sample, select clock dividers  
such that N1 and N2 are as small as possible and N3 is as large as possible. Using the  
equations above, the minimum and maximum data sampling rates and the amount of  
additional time required for the first sample can be calculated.  
Maximum sampling rate:  
N1 = 2, N2 = 2, N3 = 25  
Minimum sampling rate:  
N1 = 65535, N2 = 65535, N3 = 65535  
t = 100 x 109 * [(2)*(2)*(25)]  
t = 100 x 109 * 100  
t = 10 us  
t = 100 x 109 * [(65535)*(65535)*(65535)]  
t = 100 x 109 * [2.815 x 1014 ]  
t = 28.146 x 106 sec  
f = 10 x 106 / [(2)*(2)*(25)]  
t = 325 days, 18 hours, 23 minutes, 29 sec  
f = 10 x 106 / 100  
f = 100 Khz  
f = 10 x 106 / [(65535)*(65535)*(65535 )]  
f = 10 x 106 / [2.815 x 1014 ]  
f = 35.529 nHz  
tadd = 100 x 109 * [2 * 2]  
tadd = 100 x 109 * 4  
tadd = 400 ns  
tadd = 100 x 109 * [65535 * 65535]  
tadd = 100 x 109 * [4.295 x 109 ]  
tadd = 429.5 sec  
2.5.2  
External Clock  
The external clock input to the DAQ-16 is a TTL level (0 - 5 volt) signal. This input may be  
used to control the sampling rate directly, or it may be fed through a pre-divider (the  
multi-function timer) with the timer output controlling the A/ D sampling rate. When used to  
control the sampling rate directly, the frequency of the external clock input may be varied  
from DC to 100 KHz as long as the width of the low and high portions of the clock are a  
minimum of 1 us each. The A/ D conversion cycle will begin on each rising edge of the  
external clock input. (See Figure 2-7).  
1 usec min 1 usec min  
10 usec  
min  
Figure 2-7. Sampling Rate External Clock Pulses  
DAQ-16 Users Manual  
19  
 
When the multi-function timer is used as a pre-divider, the frequency of the external clock  
input may be varied from DC to 10 MHz as long as the high portion of the clock is at least  
30ns and the low portion is at least 50ns. Except for the first period, the sampling rate of the  
DAQ-16 will be the external clock frequency divided by the count value written to the  
multi-function timer. Since one clock pulse is required to load the initial count value into the  
timer, the first sampling interval will be one clock cycle longer than the rest. The valid range  
of count values for the multi-function timer is 2 < count < 65,535 but the resulting sampling  
rate must be less than 100KHz to assure proper operation of the A/ D converter circuitry.  
(See Figure 2-8).  
30 nsec min 50 nsec min  
100 nsec  
min  
Figure 2-8. Pre-Divider External Clock Pulses  
2.6  
Trigger Selection  
The DAQ-16 is capable of accepting an internal software trigger or an external hardware  
trigger. The trigger selection and trigger level bits in the DAQ-16 control word register select  
the trigger source and level. Upon reset, the trigger selection and trigger level bits default to  
the internal software trigger. When the internal trigger is used, an output to the  
start-of-conversion register will trigger the DAQ-16 to begin sampling the input. For  
triggering off an external event, the DAQ-16 accepts a level sensitive, TTL compatible trigger  
input from the D-62 connector. The trigger level bit in the DAQ-16 control word register  
determines which TTL level is used to trigger the A/ D converter to begin sampling.  
When an internal clock source is used, a delay of not more than 225ns will occur between the  
trigger and the first data sample. When an external clock is used, the delay will be dependent  
on the frequency and duty cycle of the clock input. If these delays are unacceptable, the clock  
and trigger circuitry can be bypassed and a start of conversion pulse can be input directly into  
the A/ D circuitry with a maximum delay of 25ns. If the user controls the start of conversion  
pulse directly, the sample will be taken on the low to high transition of the pulse, the pulse  
must have a duration of at least 10 us, and the duty cycle must be between 5 and 80 percent.  
Jumper J1, shown in Figure 2-9, configures start of conversion control.  
Start of Conversion:  
(* indicates factory default)  
J1  
DAQ-16 controlled: connect 1-2*  
User controlled: connect 2-3  
1 2 3  
Figure 2-9. Jumper J1 Configuration  
DAQ-16 Users Manual  
20  
 
2.7  
Direct Memory Access  
Direct Memory Access (DMA) transfers provide a way of transferring data from the  
DAQ-16's A/ D converter into the computer's memory without using the Central Processing  
Unit (CPU). DMA capability enables other system software to be executed while data is being  
input from the DAQ-16.  
The DAQ-16 actually implements two DMA channels. The advantage of having two DMA  
channels is that one channel can be transferring data while the second channel is being  
programmed. When the first channel is finished, the second channel will automatically take  
over and continue the data transfer. The first channel can then be re-programmed while the  
second channel is transferring data. In this way, the DAQ-16 can acquire data continuously  
until terminated by the user.  
The DAQ-16 supports 16-bit DMA transfers on channels 5, 6, and 7. The DMA channel(s) are  
selected by jumpers J8 and J9 as shown in Figure 2-10.  
DMA Channel 1  
DMA Channel 2  
J9  
J8  
DRQ7  
DACK7  
DRQ7  
DACK7  
DRQ6  
DRQ6  
DACK6  
DACK6  
DRQ5  
DRQ5  
DACK5  
DACK5  
Figure 2-10. Jumpers J8 and J9 Configuration  
WARNING: To properly implement the DMA capability, the DRQ and DACK of each  
DMA channel must be jumpered to the same number, i.e. DRQ 5/ DACK 5. If both DMA  
channels are to be used, each channel must be jumpered to a different number, i.e. channel  
1 is jumpered to DRQ 5 / DACK 5 and channel 2 is jumpered to DRQ 7/ DACK 7.  
DAQ-16 Users Manual  
21  
 
2.8  
Interrupts  
The DAQ-16 is capable of generating an interrupt from one of four sources:  
1. End of conversion signal  
2. DMA terminal count  
3. Multi-function timer output  
4. External interrupt input  
The interrupt source is software selected through the DAQ-16 control word register. The  
interrupt level is selected using the jumpers J10 and J11 as shown in Figure 2-11.  
J11  
J10  
Factory default = IRQ 5  
Figure 2-11. Jumpers J10 and J11 Configuration  
2.8.1  
External Interrupt  
The external interrupt is a TTL compatible input from the D-62 connector. An interrupt  
request is generated on a high to low transition of this input.  
DAQ-16 Users Manual  
22  
 
3. External Connections  
The DAQ-16 is equipped with a high density 62-pin connector as shown in Figure 3-1.  
22  
1
2
43  
44  
45  
46  
23  
24  
25  
26  
2 - CH1+  
4 - CH2-  
6 - CH4+  
8 - CH5-  
10 - CH7+  
12 - AOUT0  
14 - DOUT0  
6 - DOUT3  
18 - EXT TRIG  
20 - DIN1  
22 - CH0+  
24 - CH1-  
26 - CH3+  
28 - CH4-  
30 - CH6+  
32 - CH7-  
34 - AOUT1  
36 - DOUT1  
38 - EXT INT  
40 - DIN3  
42 - DIN0  
43 - CH0-  
45 - CH2+  
47 - CH3-  
49 - CH5+  
51 - CH6-  
53 - VREF0  
55 - VREF1  
57 - DOUT2  
59 - EXT CLK  
61 - DIN2  
3
4
47  
5
6
27  
28  
29  
48  
49  
7
50  
51  
8
30  
31  
9
10  
52  
53  
54  
32  
11  
12  
13  
14  
33  
34  
55  
56  
57  
35  
36  
37  
15  
16  
17  
18  
19  
58  
59  
38  
39  
40  
41  
60  
61  
62  
20  
21  
42  
Figure 3-1. 62 Pin Connector Diagram  
Analog Ground - 1, 3, 5, 7, 9, 11, 13, 44, 46, 48, 50, 52, 54  
Digital Ground - 15, 17, 19, 21, 37, 39, 41, 56, 58, 60, 62  
DAQ-16 Users Manual  
23  
 
 
CH0-,CH0+,...,CH7-,CH7+ : Analog inputs to the analog to digital converter. Amplitude and  
polarity depend upon jumper settings. The input resistance of these lines is 1.5K ohms  
typical.  
AOUT0, AOUT1: Analog outputs from the digital to analog converters. Polarity and  
maximum amplitude depend on the jumper settings and voltage references. Output  
resistance of the analog outputs is typically 70 ohms.  
VREF0, VREF1: External voltage references for the digital to analog converters. Input range  
is 0 to 5.5 volts with a no-load input resistance of 7.5K ohms.  
EXT CLK, EXT TRG, EXT INT: External clock, trigger, and interrupt inputs respectively.  
Inputs are TTL compatible.  
DOUT0, DOUT1, DOUT2, DOUT3: TTL compatible digital output lines.  
DIN0, DIN1, DIN2, DIN3: TTL compatible input lines.  
DAQ-16 Users Manual  
24  
 
4. Register Description and Programming  
The DAQ-16 uses 16 consecutive I/ O address locations in the range 0 to FFFFH. The card  
utilizes these addresses for the registers listed in Table 4-1. (* indicates registers located in  
8254 counter).  
Base + 0, 1  
Base + 2, 3  
Read/ Write 16-bit Control Word Register  
Write only 16-bit Start Conversion Register  
Read only  
16-bit A/ D Data Register  
Base + 4, 5  
Base + 6, 7  
Base + 8  
Write only 16-bit D/ A Channel 0 Register  
Write only 16-bit D/ A Channel 1 Register  
Read/ Write 8-bit Digital Input/ Output Register  
Reserved  
Base 9, A, B  
Base + C *  
Base + D *  
Base E *  
Read/ Write 8-bit Clock Rate Register (low)  
Read/ Write 8-bit Clock Rate Register (high)  
Read/ Write 8-bit Multi-function Timer Register  
Read/ Write 8-bit 8254 Control Word/ Status Register  
Base F *  
Table 4-1. DAQ-16 Address Map  
4.1  
Register Description  
4.1.1  
Control Word Register  
The control word register defines and controls many of the DAQ-16's data conversion  
functions. This register is 16-bit read/ write.  
Write  
Read  
Write  
Read  
D15 INT2  
D14 INT1  
D13 INT0  
D12 DMAEN  
D11 DMACT  
D10 LEVEL  
INT2  
INT1  
INT0  
DMAEN  
DMACH  
LEVEL  
TRIG  
D7  
D6  
D5  
D4  
D3  
D2  
D1  
D0  
RUN  
0
0
0
RUN  
EOC  
VALID  
0
0
0
CHSL2  
CHSL1  
CHSL0  
CHSL2  
CHSL1  
CHSL0  
D9  
D8  
TRIG  
CLK  
CLK  
INT2, INT1 and INT0 control the DAQ-16 interrupt source.  
INT2  
INT1  
INT0  
DESCRIPTION  
0
1
1
1
1
0
0
0
1
1
0
0
1
0
1
Interrupt disabled  
Interrupt timer 2  
Interrupt on terminal count  
External interrupt  
Interrupt on end of conversion  
DAQ-16 Users Manual  
25  
 
 
DMAEN - enables / disables DMA. When set, logic 1, DMA transfers are enabled.  
DMACT - enables the multi-channel DMA capability of the DAQ-16. When set, logic 1, a  
terminal count on the active DMA channel causes DMA transfers to begin on the "stand-by"  
channel. When cleared, logic 0, DMA transfers halt when the terminal count is reached on  
the active channel.  
DMACH - indicates which of the DAQ-16's DMA channels is currently active to transfer  
data. Logic 0 indicates DMA channel 0, logic 1 indicates DMA channel 1.  
LEVEL - selects the edge of the external trigger input. When set, logic 1, A/ D conversions  
will begin on the falling edge of the external trigger input. When cleared, logic 0, conversions  
will begin on the rising edge of the external trigger. IMPORTANT: LEVEL must be logic 0  
when internal triggering is used.  
TRIG - selects between internal and external triggers. When set, logic 1, the external trigger  
is selected.  
CLK - selects between internal and external clock sources. When set, logic 1, the external  
clock source is selected.  
RUN - when set, logic 1, the A/ D converter is placed in the 'run' mode and will begin  
converting data when a trigger is received. RUN may be cleared at any time by writing a "0"  
to it. When using DMA transfers, RUN is automatically cleared when a terminal count is  
received with DMACT set to "0".  
EOC - when set, indicates an end of conversion has taken place and the data is available in  
the A/ D converter data register.  
VALID - when set, logic 1, indicates at least one data sample was lost because it was read by  
the computer before the next sample was converted. The data was lost because the sampling  
rate was too fast for the computer to acquire data. VALID is reset by writing to the start  
conversion register.  
CHSL2, CHSL1, CHSL0 - select the multiplexer channel for the analog input signal.  
CHSL2  
CHSL1  
CHSL0  
MUX channel  
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
channel 0  
channel 1  
channel 2  
channel 3  
channel 4  
channel 5  
channel 6  
channel 7  
DAQ-16 Users Manual  
26  
 
4.1.2  
Start of Conversion Register  
The start of conversion register is 16-bit write only and performs two functions:  
1. When configured for internal triggering, writing a "0" to this register generates the  
software trigger, starting the data conversion process.  
2. Writing a "0" to this register at any time resets the VALID bit in the control word  
register. This allows the VALID bit to be reset at any time during the conversion  
process or before the event of an external trigger.  
4.1.3  
DAC0 Register  
An output to this register causes the lower twelve bits of data to be converted to an analog  
output on D/ A converter channel 0. The four most significant bits of data are ignored. This  
register is 16-bit write only.  
4.1.4  
DAC1 Register  
An output to this register causes the lower twelve bits of data to be converted to an analog  
output on D/ A converter channel 1. The four most significant bits of data are ignored. This  
register is 16-bit write only.  
The remaining four registers are contained in an 8254 counter/ timer.  
4.1.5  
Clock Rate Register (low word)  
The low word of the clock divider is contained in counter 0 of an 8254 counter/ timer. The  
output of this counter is cascaded into the input of counter 1 to produce a 32-bit timer. Mode  
2 must be selected for counter 0 with a minimum count of 2. This register is 8-bit read/ write.  
4.1.6  
Clock Rate Register (high word)  
The high word of the clock divider is contained in counter 1 of the 8254 counter/ timer. Mode  
2 must be selected for counter 1 with a minimum count of 2. This register is 8-bit read/ write.  
4.1.7  
Multi-Function Timer Register  
The multi-function timer is implemented using counter 2 of the 8254 counter/ timer. Mode  
2 must be selected for this timer with a minimum count of 2. This register is 8-bit read/ write.  
4.1.8  
8254 Control Word/Status Register  
This register is used to program the mode and report the status of the 8254 counter/ timer.  
This register is 8-bit read/ write.  
DAQ-16 Users Manual  
27  
 
4.2  
Programming the 8254 Counter/Timer  
This section provides programming information for the 8254 counter/ timer as implemented  
on the DAQ-16. For more details on the 8254, consult the Intel Micro-Processor and Peripheral  
Handbook.  
To program any of the counters contained in the 8254 counter/ timer, three steps are required:  
1. Write the configuration byte to the 8254 mode select/ status register. This byte sets  
the operating mode of the selected counter.  
2. Write the least significant byte of the count value to the selected counter register.  
3. Write the most significant byte of the count value to the selected counter register.  
The following examples illustrate the programming sequence for each of the counters in the  
8254. The variable 'base_address' is the base address of the DAQ-16 as defined by the address  
selection switches.  
Counter 0 - Clock rate register (low word)  
operating mode:  
2
minimum count value:  
configuration byte:  
2
0 / 0 / 1 / 1 / 0 / 1 / 0 / 0 = 34H  
Example:  
Example:  
Program the value 2675H into the low word of the clock rate register.  
output 34H to base_address + 0FH  
output 75H to base_address + 0CH  
output 26H to base_address + 0CH  
Program the value 0008H into the low word of the clock rate register.  
output 34H to base_address + 0FH  
output 08H to base_address + 0CH  
output 00H to base_address + 0CH  
DAQ-16 Users Manual  
28  
 
Counter 1 - Clock rate register (high word)  
operating mode:  
2
minimum count value:  
configuration byte:  
2
0 / 1 / 1 / 1 / 0 / 1 / 0 / 0 = 74H  
Example:  
Example:  
Program the value 13A4H into the high word of the clock rate register.  
output 74H to base_address + 0FH  
output A4H to base_address + 0DH  
output 13H to base_address + 0DH  
Program the value FFFFH into the high word of the clock rate register.  
output 74H to base_address + 0FH  
output FFH to base_address + 0DH  
output FFH to base_address + 0DH  
Counter 2 - Multi-function timer register  
operating mode:  
2
minimum count value:  
configuration byte:  
2
1 / 0 / 1 / 1 / 0 / 1 / 0 / 0 = B4H  
Example:  
Example:  
Program the value 000AH into the multi-function timer register.  
output B4H to base_address + 0FH  
output 0AH to base_address + 0EH  
output 00H to base_address + 0EH  
Program the value 0100H into the multi-function timer register.  
output B4H to base_address + 0FH  
output 00H to base_address + 0EH  
output 01H to base_address + 0EH  
DAQ-16 Users Manual  
29  
 
DAQ-16 Users Manual  
Version 2.20  
January 28, 1999  
Part No. 940-0032-220  
 

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