FEATURES

		20us (PA-AD12), 10us (PA-AD12-H) analog to digital (A/D) converter.
		12-Bit A/D converter with 1 LSB accuracy.
		8 differential or 16 single-ended analog input channels.
		8254 timer provides background A/D conversion.
		Jumper-configuration gain controller.
		DC/DC converter to reduce noise from PC.

DESCRIPTION

For users who require A/D only, we've got a card for you. The PA-AD12 and PA-AD12-H are 12 bit analog to digital converters. The PA-AD12 and PA-AD12-H have 8 differential/16 single-ended input channels with 12 bit 20us/10us A/Ds. An 8254 Timer/Counter, on board, allows background conversions. This module also comes with jumper-configurable gain control that allows the user to select the gain.

MODEL NUMBER

Function		PA-AD12	PA-AD12-H
A/D	Resolution	12 Bit	12 Bit
	Channels	8 Differential or 16 Single-ended	8 Differential or 16 Single-ended
	Conversion time	20 us	10 us
	Accuracy	11 Bit	11 Bit

THE EXPANSION OPTIONS

Model No.	Function
ST-DM37	Screw terminal board for A/D D/A connector
IC-XCXD	Chassis for XCI/XDI expansion cards

SYSTEM BLOCK DIAGRAM

FUNCTIONAL DESCRIPTION

The signal connector - The signal connector is a 37 pin D-type male connector. A/D channel selection - The PA-AD12(-H) can be configured for 8 differential inputs or 16 single-ended inputs. The configuration is set by an on-board jumper, the channel is software selectable. (base+2 port) Sample and hold - The PA-AD12(-H) uses a sample and hold circuit that depends on the end of conversion signal from the A/D chip. Thus, the sample and hold rate is a function of the A/D conversion speed. A/D conversion control - The A/D conversion can be triggered in three ways, they can be selected by writing a command to the A/D command port (base+3). Trigger method 1 : S/W trigger conversion This method of conversion is very easy to implement because the software is directly controlling the A/D conversions. Trigger method 2 : External clock conversion The external clock conversion consists of using an external clock or pulse, longer than 200 nanoseconds, to trigger the A/D conversion. This gives the user great flexibility in providing a trigger signal that enables one to synchronize the A/D with other devices. Trigger method 3 : 8254 timer conversion Timer conversion use the 8254 to generate a clock pulse that enablesconversion to be done in the background leaving the CPU to do more important tasks. A/D conversion When an A/D conversion takes place, (by software trig, external clock trig, etc.) the EOC (End Of Conversion) line goes high. Once the signal is received, conversion of the voltage held by the sample and hold unit is initiated. Once the converison is initiated (EOC is high), no other start conversion command will be accepted until the completion of the conversion. Upon completion of the conversion, the EOC line goes low (in timer or external clock trig mode, an interrupt will occurred). Next, the least significant byte (LSB) and the most significant byte (MSB) of the digital value for the voltage can be read from the data registers, base+0 and base+1 respectively. The 8 bits of the base+1 port are the 8 most significant bits of the A/D conversion result. The 4 most significant bits of the base+0 port are the 4 least significant bits of the A/D conversion Reading conversion result - The conversion status of the A/D can be read from the status port.

REGISTER INFORMATION

Port	Default	Direction	Function
+0	02E0H	I/O read	A/D LSB data
		I/O write	Start A/D conversion
+1	02E1H	I/O read	A/D MSB data
		I/O write	None
+2	02E2H	I/O read	A/D channel select
		I/O write
+3	02E3H	I/O read	A/D status
		I/O write	A/D command
+12	02ECH	I/O read	8254 counter 0 data (A/D internal use)
		I/O write
+13	02EDH	I/O read	8254 counter 1 data (A/D timer conversion)
		I/O write
+14	02EEH	I/O read	8254 counter 2 data (A/D timer conversion)
		I/O write
+15	02EFH	I/O read	8254 read-back status
		I/O write	8254 command

PROGRAMMING INFORMATION

Shipped with this board are Utility, Library and Sample Programs. These programs are included with the product at no additional expense. Utility Program - This program will provide comprehensive testing of various functions of the board to ensure proper operation. Library And Sample Programs - The library program provides the interface to Turbo-C, Microsoft Quick Basic, Microsoft Quick C, Microsoft GW-BASIC, IBM BASIC and Assembler. Labtech Notebook Driver - A Labtech's Notebook driver interface is available as an optional product. Window Driver - Window 3.1 and Window NT driver interface is available as an optional product.

Specifications

Analog Inputs (A/D)
Resolution	12 bits
Input channel	16 channels (single-ended)
	8 channels (differential)
Input voltage range	-5V to +5V, -10Vto +10V
	0V to +5V, 0V to +10V
Accuracy	1 bit
Conversion time	20us(PA-AD12)
	10us (PA-AD12-H)
Overvoltage	35V
Gain controller	1, 2, 5, 10, 20, 50 or user define by H/W jumper setting
Conversion method	S/W trig
	External clock trig
	Internal 8254 timer trig
Connector	37 pins D-type male connector
Counter Timer (CLK)
Controller	8254
Counters	3 16-bit down counter
	2 for A/D timer conversion
	1 for user's application
Clock source	4 MHz
Input/output type	TTL
Interface Characters
Compatible bus	IBM PC and compatibles
Data path	8 bits
Interface type	12 Bit I/O mapped
I/O location occupied	8
Port address range	100H to FF0H
Interrupt	IRQ2,3,4,5,7,10,11,12,14,15
Interrupt source	A/D end of conversion (EOC)
Power requirement	1.25A / +5V
Physical/Environmental
Operating temperature	+5 ° C to +50 ° C
Humidity	0 to 90% non-condensing
Weight	175 g
Dimension	17.5 x 12.6 x 2.0 cm