//=======================================================================
// Phillip Hoang
// Arun Gupta
// May 31, 2001
//=======================================================================
// Version 1
// This code is a complete working version.
// It sets up the UDP/IP/Ethernet Headers.
// It also has the LCD and temperature components.
// There is an while(1) loop that cycles through
//  reading the temperature, displaying it on the LCD,
//  and then sending the UDP/IP/Ethernet packet.
// The Ethernet address is the MAC address.
//=======================================================================
// For this version, the relavent headers are of the following:
// - Ethernet
//   Source: Doesn't matter, we took the one of my laptop
//   Destination: The MAC address of the router in the room
//       Embedded Systems Lab: 00-00-1d-bc-79-d7
// - IP
//   Source: Doesn't matter, we used an IP of one of the lab computers
//   Destination: 138.23.169.9
// - UDP
//   Source Port: 47098 (I don't know if this is arbitrary, gotten from
//                       packet sniffing)
//   Destination Port: 4950 (this is the port used in the listener program)
//
// NOTE: For generation the header information for the UDP/IP/Header, we
//   made a UDP socket program that sent a UDP packet.  A packet sniffer
//   was used to get the corresponding values of the header.  From then
//   we modified it accordingly so that we could transmit only our
//   needed information.
//=======================================================================

#pragma SMALL DB OE
#include <reg51.h>
#include "io.h"
#include "tmp_rec.h"

//=======================================================================

#define addr P2 
#define data P1

/*
              7     6     5     4     3    2    1    0
           +-----+-----+-----+-----+----+----+----+----+
    addr   | N/A | N/A | RST | AEN | A3 | A2 | A1 | A0 |
           +-----+-----+-----+-----+----+----+----+----+
*/

//=======================================================================

#define RxTxData	0x00		// Receive/Transmit data (port 0)
#define RxTxData1	0x02		// Receive/Transmit data (port 1)
#define TxCmd		0x04		// Transmit Command
#define TxLength	0x06		// Transmit Length
#define ISQ		0x08	        // Interrupt status queue
#define PPPtr		0x0a		// PacketPage pointer
#define PPData		0x0c		// PacketPage data (port 0)
#define PPData1		0x0e		// PacketPage data (port 1)

//=======================================================================

sbit write = P3^6;
sbit read  = P3^7;
sbit aen   = P2^4;
sbit rst   = P2^5;

//=======================================================================

// Used to Read from the Data Bus
unsigned char ioRead(unsigned char address)
{
	unsigned char value;

	addr  = (address&0x0f);
	aen   = 1;
	aen   = 0;
	read  = 0;
	value = data;
	read  = 1;

	return value;
}

// Used to write to the Data Bus
void ioWrite(unsigned char address, unsigned char value)
{
	data  = value;
	addr  = (address&0x0f);
	aen   = 1;
	aen   = 0;
	write = 0;
	write = 1;
}

//=======================================================================

int main (void)
{
	int i;
	unsigned char BusST0, BusST1;
	unsigned char temperature;

	InitIO();        
	ClearScreen();                

	////////////////////////////////////////////////////////////
	// Initialize Registers
	////////////////////////////////////////////////////////////

	// Configure RxCTL fo Promiscious mode, RxOK
	// (1) Write 0x0104 to PacketPage Pointer
	// (2) Write 0x0180 to PacketPage Data Port
	ioWrite(PPPtr,     0x04);
	ioWrite(PPPtr + 1, 0x01);
	ioWrite(PPData,     0x80);
	ioWrite(PPData + 1, 0x01);

	// Set 10BaseT, SerRxOn, SerTxOn in LineCTL
	// (1) Write 0x0112 to PacketPage Pointer
	// (2) Write 0x00c0 to PacketPage Data Port
	ioWrite(PPPtr,     0x12);
	ioWrite(PPPtr + 1, 0x01);
	ioWrite(PPData,     0xc0);
	ioWrite(PPData + 1, 0x00);

	////////////////////////////////////////////////////////////
	// Transmit
	////////////////////////////////////////////////////////////

	while(1)
	{

		temperature = PrintTemperature();

		// Send the transmit command
		ioWrite(TxCmd,     0xc0);
		ioWrite(TxCmd + 1, 0x00);
		
		// 60 bytes to be sent
		ioWrite(TxLength,     0x3c);
		ioWrite(TxLength + 1, 0x00);

		// BusST
		ioWrite(PPPtr,     0x38);
		ioWrite(PPPtr + 1, 0x01);

		// Bid for transmit
		do {
			BusST0 = ioRead(PPData);
			BusST1 = ioRead(PPData+1);
		}while(!(BusST1==0x01));

			
		/////////////////////////////////////
		// Ethernet Header
		/////////////////////////////////////

		// Send Destination (6 bytes)
		// MAC address of Router of Embedded Systems Lab (00-00-1d-bc-79-d7)
		ioWrite(RxTxData, 0x00);
		ioWrite(RxTxData+1, 0x00);
		ioWrite(RxTxData, 0x1d);
		ioWrite(RxTxData+1, 0xbc);
		ioWrite(RxTxData, 0x79);
		ioWrite(RxTxData+1, 0xd7);

		// Send Source (6 bytes)
		// MAC address of my laptop (00-00-86-45-b7-b2)
		ioWrite(RxTxData, 0x00);
		ioWrite(RxTxData+1, 0x00);
		ioWrite(RxTxData, 0x86);
		ioWrite(RxTxData+1, 0x45);
		ioWrite(RxTxData, 0xb7);
		ioWrite(RxTxData+1, 0xb2);

		// Send Protocol Type (2 bytes)
		// 0x0806 (ARP)
		// 0x0800 (IP)
		ioWrite(RxTxData, 0x08);
		ioWrite(RxTxData+1, 0x00);

		
		/////////////////////////////////////
		// IP Header
		/////////////////////////////////////

		// Version Header Length (1 byte)
		// Using IPv4
		ioWrite(RxTxData, 0x45);
		
		// Service (1 byte) 
		// Normally set to zero because not used
		ioWrite(RxTxData+1, 0x00);

		// Length (2 bytes)
		// 33 byte length
		ioWrite(RxTxData, 0x00);
		ioWrite(RxTxData+1, 0x21);
		
		// Identifier (2 bytes)
		// 0x0000
		ioWrite(RxTxData, 0x00);
		ioWrite(RxTxData+1, 0x00);
		
		// Flags Fragment offset (2 bytes)
		// 0x4000
		ioWrite(RxTxData, 0x40);
		ioWrite(RxTxData+1, 0x00);
		
		// Time to Live (1 byte)
		// 63
		ioWrite(RxTxData, 0x3f);
				
		// Protocol (1 byte)
		// ICMP (1), TCP (6), UDP (17)
		// UDP 0x11 = 17
		ioWrite(RxTxData+1, 0x11);
		
		// Checksum (2 bytes)
		// 0xb273
		// Checksum is 0xffffh - the sum of all IP header info
		ioWrite(RxTxData, 0xb2);
		ioWrite(RxTxData+1, 0x73);
		
		// Source Address (4 bytes)
		// IP address 138.23.204.32 (arbitrary)
		ioWrite(RxTxData, 0x8a);     // 138
		ioWrite(RxTxData+1, 0x17);   // 23
		ioWrite(RxTxData, 0xcc);     // 204
		ioWrite(RxTxData+1, 0x20);   // 32
		
		
		// Destination Address (4 bytes)
		// IP address 138.23.169.9 (hill)
		ioWrite(RxTxData, 0x8a);	// 138
		ioWrite(RxTxData+1, 0x17);	// 23
		ioWrite(RxTxData, 0xa9);	// 169
		ioWrite(RxTxData+1, 0x09);	// 9
		
		
		/////////////////////////////////////
		// UDP Header
		/////////////////////////////////////

		// Source Port (2 bytes)
		// Port 47098 (b7fa)
		ioWrite(RxTxData, 0xb7);
		ioWrite(RxTxData+1, 0xfa);

		// Destination Port (2 bytes)
		// Port 4950 (1356h)
		ioWrite(RxTxData, 0x13);
		ioWrite(RxTxData+1, 0x56);

		// Message Length (2 bytes)
		// 13 bytes going to be sent
		ioWrite(RxTxData, 0x00);
		ioWrite(RxTxData+1, 0x0d);

		// Checksum (2 bytes)
		// 0x0000 (no checksum used)
		ioWrite(RxTxData, 0x00);
		ioWrite(RxTxData+1, 0x00);

		// Write Message
		ioWrite(RxTxData, temperature );
		ioWrite(RxTxData+1, 't');
		ioWrite(RxTxData, 'e');
		ioWrite(RxTxData+1, 'm');
		ioWrite(RxTxData, 'p');
		ioWrite(RxTxData+1, 0x00);

	}

	return 0;
}