/*   MMC.cpp -
/*   Daniel Riiff
/*   
/*   Contains the implementation of commands needed
/*   to interface with the SPI interface of MMC card */


#include <iostream>
#include <stdio.h>
#include "SPImaster.h"
#include "MMC.h"

using namespace std;
bool InitMMC(void){
  //raise SS and MOSI for 80 clock cycles
  //SendByte(0xff) 10 times with SS high
  //RAISE SS
  int delay=0, trials=0;
  char response=0x01;
  //initialization sequence on PowerUp
  RaiseSS();
  for(int i=0;i<=9;i++)
    SendByte(0xff);
  LowerSS();  
  //Send Command 0 to put MMC in SPI mode
  SendCmd(0x00,0,0x95);
  //Now wait for READY RESPONSE
  //response=MMCgetResponse();
  if(MMCgetResponse()!=0x01)
    return false;
  
  while(response==0x01){
    cout<<"Sending Command 1"<<endl;
    RaiseSS();
    SendByte(0xff);
    LowerSS();
    SendCmd(0x01,0x00ffc000,0xff);
    response=MMCgetResponse();
  } 
  if(response==0x00)
    cout<<"RESPONSE WAS GOOD"<<endl; 
  
  RaiseSS();
  SendByte(0xff);
  
  cout<<"MMC INITIALIZED AND SET TO SPI MODE PROPERLY."<<endl;
  return true;  
}

char MMCgetResponse(){
  //Response comes 1-8bytes after command
  //the first bit will be a 0
  //followed by an error code
  //data will be 0xff until response
  int i=0;
  char response;
  
  while(i<=8){
    response=SendByte(0xff);
    if(response==0x00)
      break;
    if(response==0x01)
      break;
    i++;
  }
  return response;
}

void SendCmd(char command, int argument, char CRC){
  char cmd[6];
  char temp;
  int i;
  cmd[0]=(command|0x40);
  for(i=3;i>=0;i--){
    temp=(char)(argument>>(8*i));
    cmd[4-i]=(temp);
  }
  cmd[5]=(CRC);
  for(i=0;i<6;i++)
    SendByte(cmd[i]);
}

//WRITE a BLOCK starting at address
bool MMCwriteBlock(char *Block, int address){
  char busy,dataResp;
  //Block size is 512 bytes exactly
  //First Lower SS
  LowerSS();
  //Then send write command
  SendCmd(24,address,0xff);
  if(MMCgetResponse()==00){
    //command was a success - now send data
    //start with DATA TOKEN = 0xFE
    SendByte(0xfe);
    //now send data
    for(int count=0;count<512;count++){
      SendByte(Block[count]);
    }
    //data block sent - now send checksum
    SendByte(0xff);
    SendByte(0xff);
    //Now read in the DATA RESPONSE token
    dataResp=SendByte(0xff);
    //Following the DATA RESPONSE token
    //are a number of BUSY bytes
    //a zero byte indicates the MMC is busy
    busy=SendByte(0xff);
    while(busy==0){
      busy=SendByte(0xff);
    }
    dataResp=dataResp&0x0f;	//mask the high byte of the DATA RESPONSE token
    RaiseSS();
    SendByte(0xff);
    if(dataResp==0x0b){
      cout<<"DATA WAS NOT ACCEPTED BY CARD -- CRC ERROR"<<endl;
      return false;
      }
    if(dataResp==0x05)
      return true;
      
    cout<<"Invalid data Response token."<<endl;
    return false;
 }
  cout<<"Command 24 (Write) was not received by the MMC."<<endl;
  return false;
}