[[TOC(heading=Table of Contents, Docs/Prog/Manual/DeviceSupport/*)]] [[PageOutline]]

= DIO =

The 825 main board is equipped with four digital input and four digital output ports. DIO option cards may be used for additional I/O options. Option cards contain eight ports which may be used as a combination of inputs and outputs.

== Digital I/O ==

The console command prompt may be used for simple DIO testing.
{{{
echo “L000000020000000F” > /dev/mnbd
}}}
This sets the state of the mainboard digital outputs. The “L” is the command, the following 8 characters or four hexadecimal bytes represent the state desired. The final 8 characters or four hexadecimal bytes represent a mask of which outputs are to be affected. In this example “F” is used as the mask to set the state of all four on-board outputs.

{{{
# echo “I” > /dev/mnbd
}}}
This requests the status of the mainboard digital I/O.

{{{
# cat < /dev/mnbd
}}}
response:

{{{
# IA000000000
}}}
The last 8 character of the response are hexadecimal digits. Of these the first 4 digits are the state of the digital inputs. The final 4 digits are the state of the outputs. If the input 1 only is active the response is:

{{{
# IA000010000
}}}
If inputs one and two are active the response is:

{{{
# IA000030000
}}}
If inputs one, two, three, and four are active the response is:

{{{
# IA0000F0000
}}}
Only a single hexadecimal digit is needed to represent the state of the four mainboard inputs.

||Response||Input 1||Input 2||Input 3||Input 4||
||0||Off||Off||Off||Off||
||1||On||Off||Off||Off||
||2||Off||On||Off||Off||
||3||On||On||Off||Off||
||4||Off||Off||On||Off||
||5||On||Off||On||Off||
||6||Off||On||On||Off||
||7||On||On||On||Off||
||8||Off||Off||Off||On||
||9||On||Off||Off||On||
||A||Off||On||Off||On||
||B||On||On||Off||On||
||C||Off||Off||On||On||
||D||On||Off||On||On||
||E||Off||On||On||On||
||F||On||On||On||On||

''For additional structure formats refer to MainboardProtocol''

The lib825 library provides functions to facilitate applications performing digital I/O tasks.

To perform these tests with DIO option cards replace /dev/mnbd with /dev/wt1 (for the first DIO option card), /dev/wt2 (for the second installed DIO option card), etc...

The following example shows program code to read and set DIO ports.
{{{
#!Lineno
#!c
extern uint32 g_nRepIOIntv;

extern struct set_dio_struct mnbd_set_dio;
extern struct mnbd_dio_status_struct mnbd_dio_status;

// Read I/O status every 100 ms
g_nRepIOIntv = 100;
MnBdRequest(MNBD_DEV, MNBD_REQ_REP_IO_STATUS, NO_WAIT_ACK);

sleep(1);

while(1)
{
   if(CheckIORcv(MNBD_DEV))
   {
      if((mnbd_dio_status.inputs & 1) != 0)
      {
           // Input 1 active -- Set output 1 and break out of loop

           mnbd_set_dio.output = 0x01;
	   mnbd_set_dio.mask = 0x0F;
           MnBdRequest(MNBD_DEV, MNBD_REQ_SET_IO_STATUS, NO_WAIT_ACK);
           break;
      }
   }
}

// Stop repeating I/O status
g_nRepIOIntv = 0;
MnBdRequest(MNBD_DEV, MNBD_REQ_REP_IO_STATUS, NO_WAIT_ACK);

}}}
To use this example with a DIO option card replace MNBD_DEV with the number of the installed DIO option card such "1" for the first DIO option card, or "2" for the second installed DIO option card.

If MNBD_REQ_REP_IO_STATUS is used for repeat status on multiple DIO cards or the mainboard and another DIO card at the same time it will be impossible to mnbd_dio_status structure and determine which card is providing the input. However, an array of structures is provided dio_status[x] where x = 0 mainboard, x = 1 first DIO card, x = 2 second DIO card, etc...

For digital I/O event operations refer to the DioEvent class.

== DIO Events ==

=== About ===
This document will guide the programmer through the process of creating and using a simple DIO Event using the DioEvent class provided in the standard library (lib825). DIO Events are processed by the mainboard in order to allow a level of redundancy. Should the OPI board kernel crash the mainboard will continue to provide relay functionality and will disable events when their thresholds are reached.

=== The Code ===
To use a DIO event follow the example code below.

{{{
#!Lineno
#!c

// required include file from lib825
#include "DioEvent.h"

int main() {
  // indicator startup (open mainboard, etc)

  // dio example
  DioEvent event;

  int scale = 1;
  int board = 0;
  int pin = 0x01;
  float fTarget = 250.00;

  // set up the event
  int myEvent = event.addEvent(scale,EVENT_GROSS,EVENT_LESS,fTarget,board,pin);

  // optionally add a conditional statement to it
  event.addCondition(myEvent,scale,EVENT_GROSS,EVENT_GREATER,0,EVENT_AND);

  // start the individual event 
  event.startEvent(myEvent);

  // OR you can start all events
  event.startAll();

  // indicator shutdown (close mainboard, etc)
  return 0;
}
}}}

The above code would create an event that would enable board 0 (mainboard) pin 0 when the gross weight of scale 1 is less than 250.00 and greater than 0.00.

== DIO Counting ==

=== Description ===

Mainboard software 1.15 is required for counting feature. Kernel 2009-10-07 or later is required. All four inputs of the mainboard may be used for counting. The DIO cards allow any one of inputs 1 - 7 to be used for counting. Input 8 may also be used for counting. This allows for up to two inputs per DIO card to be used for counting.

=== Example ===

{{{
#!Lineno
#!c

#include <stdio.h>
#include <stdlib.h>

#include "kypdbeep.h"
#include "lcd.h"
#include "mnbdcomm.h"

extern uint16 g_dio_count;

extern int g_keycnt;

extern uint8 g_keybuf[KEYBUF_SIZE];
extern struct set_dio_struct mnbd_set_dio;

int main() {

	char szCnt[41];

	struct timespec delaytm;
	delaytm.tv_sec = 0;
	delaytm.tv_nsec = 1000000;  // 1 ms

	InitLCD();
	ClearLCD();

	OpenBeeper();

	PrintLCD("DIO Counter Test\r");
	PrintLCD("Press '1' - '4' to toggle outputs");

	int input;

	// Note - all four input pins of mainboard may be used for counting, options card may use only one of inputs 1 - 7 for
	// counting and input 8 may always be used for counting.

	OpenMnBd(MNBD_DEV);

	struct {
		int init_cnt;
		int prescaler;
		DIOSetReg up_or_down;
		DIOSetReg low_or_high;
	} test[4] = {
			// Experiment with different options to observe different counter behavior
			//  Count  Prescaler    Count Up or down    Count on low to high, or high to low
			{ 		0,  	1, 		dioSetCountUp, 		dioSetCountLowToHigh },
			{ 	   10, 		1,		dioSetCountDown, 	dioSetCountLowToHigh },
			{ 		0, 		1, 		dioSetCountUp, 		dioSetCountHighToLow },
			{ 	  100, 		2, 		dioSetCountDown, 	dioSetCountLowToHigh }
	};

	for(input = 1; input <= 4; input++)
	{
		if(SetDIOCounter(MNBD_DEV, input, dioSetCount, test[input-1].init_cnt, WAIT_ACK) != MNBD_REQ_ACK_RCVD)
		{
			PrintLCD("Cannot set count\r");
		}

		if(SetDIOCounter(MNBD_DEV, input, dioSetPrescaler, test[input-1].prescaler, WAIT_ACK) != MNBD_REQ_ACK_RCVD)
		{
			PrintLCD("Cannot set prescaler\r");
		}

		if(SetDIOCounter(MNBD_DEV, input, test[input-1].up_or_down, 0, WAIT_ACK) != MNBD_REQ_ACK_RCVD)
		{
			PrintLCD("Cannot set count up\r");
		}

		if(SetDIOCounter(MNBD_DEV, input, test[input-1].low_or_high, 0, WAIT_ACK) != MNBD_REQ_ACK_RCVD)
		{
			PrintLCD("Cannot set count low to high\r");
		}

		if(SetDIOCounter(MNBD_DEV, input, dioEnableCounter, 0, WAIT_ACK) != MNBD_REQ_ACK_RCVD)
		{
			PrintLCD("Cannot enable counter\r");
		}
	}

	input = 1;

	mnbd_set_dio.output = 0;

	int req_cnt = 3000;
	int n;
	GetDIOCounter(MNBD_DEV, input, dioGetCount, NO_WAIT_ACK);

	while(1)
	{
		ReadKeypad();
		if(g_keycnt > 0)
		{
			g_keycnt = 0;
			if(g_keybuf[0] == ESC)
				break;
			// Keypad keys "1" through "4" will toggle state of output which is looped back to input
			// so that we can observe operation of counter
			if(g_keybuf[0] >= '1' && g_keybuf[0] <= '4')
			{
				mnbd_set_dio.mask = 0x000F;
				n = g_keybuf[0] - '1';
				if(mnbd_set_dio.output & (1 << n))
				{
					mnbd_set_dio.output &= ~(1 << n);
					LocateLCD(n * FONT_WIDTH * 10, FONT_HEIGHT * 3);
					PrintLCD("  ");
				}
				else
				{
					mnbd_set_dio.output |= (1 << n);
					LocateLCD(n * FONT_WIDTH * 10, FONT_HEIGHT * 3);
					PrintLCD("on");
				}

				MnBdRequest(MNBD_DEV, MNBD_REQ_SET_IO_STATUS, WAIT_ACK);
				nanosleep(&delaytm, NULL);

				input = n + 1;
				req_cnt = 1;
			}
		}

		req_cnt--;
		if(req_cnt == 0)
		{
			GetDIOCounter(MNBD_DEV, input, dioGetCount, NO_WAIT_ACK);
			req_cnt = 3000;
		}

		nanosleep(&delaytm, NULL);

		if(CheckDIOCountRcv(MNBD_DEV))
		{
			sprintf(szCnt, "%6d", g_dio_count);
			LocateLCD((input - 1) * FONT_WIDTH * 10, FONT_HEIGHT * 2);
			PrintLCD(szCnt);

			if(input == 4)
				input = 1;
			else
				input++;

			req_cnt = 5;
		}
	}

	// Done - disable the counters
	for(input = 1; input <= 4; input++)
	{
		if(SetDIOCounter(MNBD_DEV, input, dioDisableCounter, 0, WAIT_ACK) != MNBD_REQ_ACK_RCVD)
		{
			PrintLCD("Cannot disable counter\r");
		}
	}

	CloseMnBd(MNBD_DEV);

	ClearLCD();

	return 0;
}


}}}