VAIODIO8

VAST 8 Digital, 4 Analog to Digital Converter (VAIODIO8)

General Description

The VAIODIO8 provides 8 digital I/O lines, four 8-bit analog to digital converter inputs, and a single 8-bit digital to analog converter output. Full voltage range for both inputs and outputs is 5V.

Note: On our SBC2000 engines that include VAST, the LCD and keypad share some lines with the VAST connector. In most cases the VAST peripheral will interpret the signals correctly in spite of any operations involving the LCD or keypad. However, in the case of the VAIO8 board, the TLC5628 DAC chip may get confused if it happens to get just the right combination of extraneous signals. If the upper or lower four bits of keypad scan data or a character sent to the LCD happens to match the DAC's VAST address, and then the next set do not match, the DAC chip on the VAIO8 interprets the signal as a "load new value" operation, and causes new values to be loaded for all channels.

a) The easiest workaround is to use either the VAST AIODIO8 or the VAST AIO12 board instead of the VAIO8 board. If you only need one channel, use the VAST AIODIO8. If you need more than one channel use the VAST AIO12 board. These boards use different chips and don't exhibit the problem.

b) Alternatively, you can create a custom VAST cable by disconnecting the VA3 line from the cable and re-routing it to an available digital output bit on the SBC2000. Then write your application to keep the digital output bit at 1 level at all times except when you want to communicate with the board.

Quick Start

1. Install ADDR jumpers to pins 3-4, 5-6 and 7-8 (as shipped). This is an IIC peripheral, and will always be at VAST address 15. The address jumpers are used to select among more than one IIC peripheral. With the jumpers in this position:

The digital I/O are at bit numbers 0 through 7.
The analog inputs are on channels 0 through 3.
The analog output is on channel 0.

2. Connect the VAST cable to the SBC2000

3. Execute the following code:

GLOBAL i AS INTEGER 
CONSTANT crlf AS STRING = "\013\010" 
VDIO_CONFIG(0,0)
REM Turn each bit on 
FOR i = 0 TO 7 
	VSET(i) 
NEXT i 

REM Read an analog input 
DO 
	VAIN_CONFIG(0,0)
	PRINT VAIN(0), crlf 
LOOP UNTIL 0

Software Control

VDIO_CONFIG() When executing func=0 and value=0 this subroutine configures digital extensions to work with the VAIODIO8.
VSET() configures an I/O line as an output and sets it to high. Valid addresses 0-63. See "VAIODIO8 Address Jumpers", below.
VRESET() configures an I/O line as an output and sets it to low.
VTEST() configures an I/O line as an input and return the state of the input.
VINP() configures and reads all 8 digital I/O lines on the VAIODIO8 as input.
VOUT() will write the specified byte to the specified port. Configures as input and writes all 8 digital I/O lines on the VAIODIO8.
VAIN_CONFIG() configures extensions for running analog to digital conversions. Func determines which parameter is being configured. Value sets the parameter selected by func.

VAIN_CONFIG() Settings for VAIODIO8

Func Setting Value Configuration

0 Select Peripheral 0 Selects VAIODIO8

1 Input organization 0 AIN0-3 are single ended input

1 AIN0-2 are differential w/ respect to AIN3

2 AIN0-1 are single ended, AIN2-3 are a differential pair

3 AIN0-1 and AIN2-3 are differential pairs

AIN() starts a conversion on the specified ADC channel on a VAIODIO8 and returns the 8-bit result. Return values are 0-255.
AOUT_CONFIG() selects the type of peripheral to use for digital to analog conversions. Func is always zero. To configure the extensions to use the VAIODIO8, call AOUT_CONFIG() with the value argument set to 0. There is no need to call AOUT_CONFIG before every conversion. Once extensions are configured, they will remain so until changed.
AOUT() sets the output level on the specified DAC channel on a VAIODIO8. Valid values are 0-7.

VAIODIO8 Address Jumpers

I/O Connector

Pin	Signal	Pin	Signal	Note
1	DGND	9	DIO6	AGND :
2	+5V	10	DIO7
3	DIO0	11	AGND
4	DIO1	12	AOUT
5	DIO2	13	AIN0
6	DIO3	14	AIN1
7	DIO4	15	AIN2
8	DIO5	16	AIN3

All digital lines are software programmable as inputs or outputs.

Voltage Range

Single-ended and differential input conversions are available. In single-ended mode, the input voltage range is 0-5V. in differential mode, the voltage range is -2.5V to +2.5V with respect to each other. In no case may an input voltage be less than ground.