/************************************************************************************************ * Project: USB AVR-ISP * Author: Christian Ulrich
 * Contact: christian at ullihome dot de
 * * Creation Date: 2007-03-22 * Copyright: (c) 2007 by Christian Ulrich * License: GPLv2 ***********************************************************************************************/
#include <avr/io.h>
#include <util/delay.h>
#include <stdio.h>
#include "isp.h"

uint8_t ISP_Speed = 1;
uint8_t ISP_Status = 0;

#define ISP_DIVIDER (uint8_t)(22 * 1024 / ((33 + 22) * 25.6)) 

uint8_t ISP_getsupplyvoltage(void)
{
  uint16_t supply;
  ISP_SUPPLY_PORT &= ~(1<<ISP_SUPPLY);

  ADCSRA = (1<<ADEN) | (1<<ADPS1) | (1<<ADPS0);    // Frequenzvorteiler 
                               // setzen auf 8 (1) und ADC aktivieren (1)
  ADMUX = 1;                      // Kanal waehlen
  ADMUX |= (1<<REFS1) | (1<<REFS0); // interne Referenzspannung nutzen 
  ADCSRA |= (1<<ADSC);              // eine ADC-Wandlung 
  while ( ADCSRA & (1<<ADSC));
  supply = ADCW;
  ADCSRA |= (1<<ADSC);            // eine Wandlung "single conversion"
  while ( ADCSRA & (1<<ADSC) );
  supply = ADCW;
  return (supply + ISP_DIVIDER/2) / ISP_DIVIDER;
}

void ISP_checkstatus(void)
{
  uint8_t newstatus;

  if (  (ISP_getsupplyvoltage() > 45) )
    newstatus = ISP_STATUS_CONNECTED_OK;
  else if (  (ISP_getsupplyvoltage() > 20) && (ISP_getsupplyvoltage() < 45) )
    newstatus = ISP_STATUS_CONNECTED_NOT_OK;
  else
    newstatus = ISP_STATUS_DISCONNECTED;
  if (newstatus != ISP_Status)	  
    {
	  if (ISP_statuschanged != NULL) ISP_statuschanged(newstatus);
      ISP_Status = newstatus;
	}
}
void ISP_pulsesck(void)
{
  ISP_OUT |= (1 << ISP_SCK);     /* SCK high */  _delay_ms(0.07);   ISP_OUT &= ~(1 << ISP_SCK);    /* SCK low */  _delay_ms(0.07); }
void ISP_spienable(uint8_t speed) 
{
  switch (speed)
    {
	  case 2:/* enable SPI, master, 93,75 kHz SCK */
	    {          SPCR = (1 << SPE) | (1 << MSTR) | (1 << SPR1)| (1 << SPR0);          SPSR = 0;
	      break;
        }  
      case 3:
	    {
          /* enable SPI, master, 187,5Hz SCK */          SPCR = (1 << SPE) | (1 << MSTR) | (1 << SPR1);          SPSR = 0;
		  break;		}
      case 4:
	    {
          /* enable SPI, master, 375kHz SCK */          SPCR = (1 << SPE) | (1 << MSTR) | (1 << SPR1);          SPSR = (1 << SPI2X);
		  break;		}		       case 5:
	    {
          /* enable SPI, master, 750kHz SCK */          SPCR = (1 << SPE) | (1 << MSTR) | (1 << SPR0);          SPSR = 0;
		  break;		}
	  case 6:
	    {
          /* enable SPI, master, 1,5 MHz SCK */          SPCR = (1 << SPE) | (1 << MSTR) | (1 << SPR0);          SPSR = (1 << SPI2X);
		  break;		}			 	  case 7:
	    {
          /* enable SPI, master, 3 MHz SCK */          SPCR = (1 << SPE) | (1 << MSTR);          SPSR = 0;
		  break;		}			     }}
#define ISP_spidisable() SPCR = 0
void ISP_connect() 
{
  /* all ISP pins are inputs before */  /* now set output pins */  ISP_DDR |= (1 << ISP_RST) | (1 << ISP_SCK) | (1 << ISP_MOSI);  /* reset device */  ISP_OUT &= ~(1 << ISP_RST);   /* RST low */  ISP_OUT &= ~(1 << ISP_SCK);   /* SCK low */  /* positive reset pulse > 2 SCK (target) */  _delay_ms(0.10);   ISP_OUT |= (1 << ISP_RST);    /* RST high */  _delay_ms(0.10);                   ISP_OUT &= ~(1 << ISP_RST);   /* RST low */  ISP_spienable(ISP_Speed);}void ISP_disconnect() 
{  ISP_DDR &= ~((1 << ISP_RST) | (1 << ISP_SCK) | (1 << ISP_MOSI));  ISP_OUT &= ~((1 << ISP_RST) | (1 << ISP_SCK) | (1 << ISP_MOSI));  ISP_spidisable();}uint8_t ISP_transmit(uint8_t send_byte) 
{  uint8_t rec_byte = 0;  uint8_t i;
  
  if (ISP_Speed == 1)
    {      for (i = 0; i < 8; i++) 
        {          /* set MSB to MOSI-pin */          if ((send_byte & 0x80) != 0) 
            ISP_OUT |= (1 << ISP_MOSI);  /* MOSI high */          else            ISP_OUT &= ~(1 << ISP_MOSI); /* MOSI low */          /* shift to next bit */          send_byte  = send_byte << 1;          /* receive data */          rec_byte = rec_byte << 1;          if ((ISP_IN & (1 << ISP_MISO)) != 0) 
            rec_byte++;          /* pulse SCK */
		  ISP_pulsesck();        }      return rec_byte;
    }
  else if (ISP_Speed == 0) return 1;  else
    {
      SPDR = send_byte;      while (!(SPSR & (1 << SPIF)));      return SPDR;	}}
uint8_t ISP_enterprogrammingmode() 
{  uint8_t check;  uint8_t count = 32;  while (count--) 
    {      ISP_transmit(0xAC);      ISP_transmit(0x53);      check = ISP_transmit(0);      ISP_transmit(0);      if (check == 0x53)        return 0;      ISP_spidisable();      ISP_pulsesck();      ISP_spienable(ISP_Speed);    }  return 1;  /* error: device dosn't answer */ 
}
void ISP_erase()
{
  ISP_transmit(0xAC);  ISP_transmit(0x80);  ISP_transmit(0x00);  ISP_transmit(0x00);}

uint8_t ISP_readsignaturebyte(uint8_t addr)
{
  ISP_transmit(0x30);  ISP_transmit(0x00);  ISP_transmit(addr);  return ISP_transmit(0x00);}

uint8_t ISP_deviceisbusy()
{
  ISP_transmit(0xf0);  ISP_transmit(0x0);  ISP_transmit(0x0);  return ISP_transmit(0x0) & 1;}