Change a 7 seg display from CC to CA in code? Answered

I am not as familiar with C/C++ as i am with Arduino. I am wanting to change this code from Common Cathode to Common Anode.
How can i do this?

//_____________________ fuse.c
#define F_CPU 8000000UL

#include <avr/pgmspace.h>
#include <avr/eeprom.h>
#include <avr/io.h>
#include <avr/interrupt.h>
#include <util/delay.h>

#define _REVERSE

#define _OPT_BUTTON_
/*
. document tab-stop set to 4, best viewed w/ vi set to ":set ts=4"

. description
  this project is created so that if i could revert the RESET fuse change and flash via
  SPI again.

. features
  . reads device signature and hi-low fuses for hi-voltage serial programmable attinys
  . reset hi-low fuses to factory default on target devices
  . layout to drop-on attiny13, attiny25/45/85 8 pin devices targets
  . attiny24/44/84 targets needs additional breadboard and jumper wires
  . standalone operations, fuses show on 7 segment display

. project fuse setting
  avrdude -c usbtiny -p t2313 -V -U lfuse:w:0xe4:m -U hfuse:w:0xdf:m -U efuse:w:0xff:m

. parts list
  . attiny2313
  . 4x7 segment LED display
  . 1k resistor x 2
  . 2n2222 NPN transistor or equivalent
  . 78L05
  . mini breadboard 170 tiepoints
  . +12V battery source

. opearation
  . place 8 pin target device on breadboard
  . for 14 pin targets, jumper wire to breadboard
  . apply 12V power
  . display shows device name upon identification
  . press and release button to cycle display content
  . displays device name, fuse hi bits, fuse low bits and fuse extended bits
  . long press and release button to reset fuse to factory default

. references and related projects
  . datasheets
  . avrdoper http://www.obdev.at/avrusb/avrdoper.html/
  . mightyohm http://www.mightyohm.com/blog/2008/09/arduino-based-avr-high-voltage-programmer/


                 Gd 12V
                 Gd Rt V+ Ck MI MO (tinyusb programmer)
                  +  +  +  +  +  +
   +=====================================================+
   |  .  .  .  .  .  I  .  .  .  .  .  .  .  .  .  .  .  | [I]n (78L05)
   |  .  .  .  .  C  .  .  .  .  .  .  .  .  .  .  .  .  | [C]ommon
   |  .  .  .  .  .  .  O  .  .  .  .  .  .  .  .  .  .  | [O]ut
   | (v)(d)(b)(c) +--------o (v) .  .  .  .  . (d)(c) .  |
   |  +--+--+--+  |  o  +--+-(1)-A--F-(2)(3)-B--+--+  .  |
   | |+         | 1k | |+ b7..6..5..4..3..2..1..0 d6|    |
   | |         -| |  1k|R d0..1 a1..0 d2..3..4..5  -|    |
   |  +--+--+--+  o  |  +--+--+--+--+--+--+--+--+--+  .  |
   |  .  .  .  .  .  o  -  -  E  D (.) C  G (4) -  -  .  |
   |  o--------------o  .  .  .  .  .  .  .  .  .  .  .  |
   |  . (a) .  E  B  C  . (a) .  .  .  .  .  . (b) .  .  | EBC of 2n2222
   |  .  .  .  .  .  .  .  .  .  .  .  .  .  o--B--o  .  |
   +=====================================================+
                    (p)(p)                                 join (p)(p) during programming

      SDO   SDI
    +--+--+--+
   |+    SII  |
   |R        -|
    +--+--+--+
      SCI

#define HIV _BV(7) //b7 .. RESET
#define VCC _BV(6) //b6 .. (v)
#define SDO _BV(0) //b0 .. (d)

#define SCI _BV(0) //d0 .. (a)
#define SII _BV(5) //d5 .. (b)
#define SDI _BV(6) //d6 .. (c)

*/

#define BUTTON_DDR   DDRD
#define BUTTON_PORT  PORTD
#define BUTTON_PIN   _BV(4)

#define SEG_A_PB _BV(5)
#define SEG_B_PB _BV(1)
#define SEG_C_PB 0x00
#define SEG_D_PB 0x00
#define SEG_E_PB 0x00
#define SEG_F_PB _BV(4)
#define SEG_G_PB 0x00
#define SEG_d_PB 0x00
#define DIGIT_0_PB _BV(6)
#define DIGIT_1_PB _BV(3)
#define DIGIT_2_PB _BV(2)
#define DIGIT_3_PB 0x00

#define SEG_A_PD 0x00
#define SEG_B_PD 0x00
#define SEG_C_PD _BV(2)
#define SEG_D_PD _BV(7)  // d.7 maps to a.1
#define SEG_E_PD _BV(1)
#define SEG_F_PD 0x00
#define SEG_G_PD _BV(3)
//#define SEG_d_PD 0x00
#define SEG_d_PD _BV(6)  // d.6 maps to a.0
#define DIGIT_0_PD 0x00
#define DIGIT_1_PD 0x00
#define DIGIT_2_PD 0x00
#define DIGIT_3_PD _BV(4)

#ifdef _REVERSE
#define HOLD_DDR_VAL 0x60
#define HOLD_VAL   0x40
#else
#define HOLD_DDR_VAL 0x18
#define HOLD_VAL   0x08
#endif


#define SEGS_STAY(v) \
   (((v & _BV(6)) ? 1 : 0) +\
((v & _BV(5)) ? 1 : 0) +\
((v & _BV(4)) ? 1 : 0) +\
((v & _BV(3)) ? 1 : 0) +\
((v & _BV(2)) ? 1 : 0) +\
((v & _BV(1)) ? 1 : 0) +\
((v & _BV(0)) ? 1 : 0)) | 0x40

#define SEGS_PORT_DET(p, v) \
   (((v & _BV(6)) ? SEG_A_P##p : 0) | \
((v & _BV(5)) ? SEG_B_P##p : 0) | \
((v & _BV(4)) ? SEG_C_P##p : 0) | \
((v & _BV(3)) ? SEG_D_P##p : 0) | \
((v & _BV(2)) ? SEG_E_P##p : 0) | \
((v & _BV(1)) ? SEG_F_P##p : 0) | \
((v & _BV(0)) ? SEG_G_P##p : 0))

#define SEGS_PORT(v) {SEGS_STAY(v),SEGS_PORT_DET(B, v),SEGS_PORT_DET(D, v)}
#define SEGS_B (SEG_A_PB|SEG_B_PB|SEG_C_PB|SEG_D_PB|SEG_E_PB|SEG_F_PB|SEG_G_PB|SEG_d_PB)
#define SEGS_D (SEG_A_PD|SEG_B_PD|SEG_C_PD|SEG_D_PD|SEG_E_PD|SEG_F_PD|SEG_G_PD|SEG_d_PD)

#define DIGITS_B (DIGIT_0_PB|DIGIT_1_PB|DIGIT_2_PB|DIGIT_3_PB)
#define DIGITS_D (DIGIT_0_PD|DIGIT_1_PD|DIGIT_2_PD|DIGIT_3_PD)

#define USED_B (SEGS_B|DIGITS_B)
#define USED_D (SEGS_D|DIGITS_D)

/*
       ___a__
      |      |
     f|      | b
       ___g__
     e|      | c
      |      |
       ___d__
*/
//_____________________ abc defg
#define LTR_0 0x7e // 0111 1110
#define LTR_1 0x30 // 0011 0000
#define LTR_2 0x6d // 0110 1101
#define LTR_3 0x79 // 0111 1001
#define LTR_4 0x33 // 0011 0011
#define LTR_5 0x5b // 0101 1011
#define LTR_6 0x5f // 0101 1111
#define LTR_7 0x70 // 0111 0000
#define LTR_8 0x7f // 0111 1111
#define LTR_9 0x7b // 0111 1011
#define LTR_A 0x77 // 0111 0111
#define LTR_b 0x1f // 0001 1111
#define LTR_C 0x4e // 0100 1110
#define LTR_d 0x3d // 0011 1101
#define LTR_E 0x4f // 0100 1111
#define LTR_F 0x47 // 0100 0111

#define LTR_P 0x67 // 0110 0111
#define LTR_G 0x5e // 0101 1110
#define LTR_n 0x15 // 0001 0101
#define LTR_r 0x05 // 0000 0101
#define LTR_t 0x0f // 0000 1111
#define LTR__ 0x00 // 0000 0000

uint8_t EEMEM digit2ports[][3] = {
SEGS_PORT(LTR_0), SEGS_PORT(LTR_1), SEGS_PORT(LTR_2), SEGS_PORT(LTR_3),
SEGS_PORT(LTR_4), SEGS_PORT(LTR_5), SEGS_PORT(LTR_6), SEGS_PORT(LTR_7),
SEGS_PORT(LTR_8), SEGS_PORT(LTR_9), SEGS_PORT(LTR_A), SEGS_PORT(LTR_b),
SEGS_PORT(LTR_C), SEGS_PORT(LTR_d), SEGS_PORT(LTR_E), SEGS_PORT(LTR_F),
SEGS_PORT(LTR_r), SEGS_PORT(LTR_P), SEGS_PORT(LTR_G), SEGS_PORT(LTR_n),
SEGS_PORT(LTR_t), SEGS_PORT(LTR__),
};

enum {
POS_0, POS_1, POS_2, POS_3, POS_4, POS_5, POS_6, POS_7,
POS_8, POS_9, POS_A, POS_b, POS_C, POS_d, POS_E, POS_F,
POS_r, POS_P, POS_G, POS_n, POS_t, POS__,
};

#define ST_HOLD  0x80
#define ST_PRESSED 0x40
#define ST_BUTTON   (ST_HOLD|ST_PRESSED)
#define ST_TICKED 0x20
#define ST_12HR  0x10
#define ST_REFRESH 0x08
#define ST_BUZZ     0x04
#define ST_SETUP    0x03

#define ST_SENSE ST_BUZZ

volatile uint8_t busy=0;
volatile uint8_t state=ST_REFRESH|ST_12HR;
volatile uint8_t dim=1;

uint8_t  pos=0, stays;
uint8_t  mode=0;
#ifdef _OPT_SENSE_
uint16_t charged=0;
#endif
uint16_t button=0;
uint16_t clicks=0, ticks=0;

//_______________________ ticks per second and devired values
#define TPS   (F_CPU/256)
#define TPS_2 (TPS/2)
#define TPS_4 (TPS/4)

#define LONG_HOLD (TPS/3)

#define NUM_DIGITS 4

static const uint8_t digit_mapb[] PROGMEM = { 0x40,0x08,0x04,0x00 };
static const uint8_t digit_mapd[] PROGMEM = { 0x00,0x00,0x00,0x10 };
//_________________ list of porta..c,ddra..c,stay * number_of_digits
uint8_t output[3 * NUM_DIGITS];
uint8_t *ioptr = output;
uint8_t dot = 0x00;

//__________________________________________________
ISR(TIMER0_OVF_vect) {

clicks++;

if (clicks >= TPS) {
  clicks = 0;
  state |= ST_TICKED;
  ticks++;
}//if

if (stays & 0x0f) { stays--; return; }
stays >>= dim;

DDRA  &= ~(USED_D>>6);
DDRB  &= ~USED_B;
DDRD  &= ~(USED_D&0x3f);
PORTA &= ~(USED_D>>6);
PORTB &= ~USED_B;
PORTD &= ~(USED_D&0x3f);

if (stays) { stays--; return; }

if (busy) return;

#ifdef _OPT_BUTTON_
//___________ scan button
PORTD |= BUTTON_PIN;
_delay_us(1);  // allow pull-up to settle
if (PIND & BUTTON_PIN) {
  if (button) {
   if (button > 30) {
    //_________ released
    if (button > LONG_HOLD)
     state |= ST_HOLD;
    else
     state |= ST_PRESSED;
    stays = 0x14;
   }//if
  }//if
  else {
   stays = 0x10;
  }//else
  button = 0;
}//if
else {
  //_____________ pressed
  button++;
  if (button > LONG_HOLD) { // show long hold
#ifdef _REVERSE
   DDRB |= HOLD_DDR_VAL; PORTB |= HOLD_VAL;
#else
   DDRD |= HOLD_DDR_VAL; PORTD |= HOLD_VAL;
#endif
  }//if
}//else
PORTD &= ~BUTTON_PIN;
DDRD  &= ~(USED_D&0x3f);
PORTD &= ~(USED_D&0x3f);
if (state & ST_BUTTON) return;
if (button) return;
#endif

#ifdef _OPT_SENSE_
if (!charged && (state & ST_SENSE)) {
  state &= ~ST_SENSE;
  DDRB  = 0x00; PORTB = 0x00;
  DDRD  = 0x00; PORTD = 0x00;
  _delay_us(1);
  //_________ charge sensor led
  charged = 1;
  //SENSE_CHARGE

  DDRA  |=  SEGS_D>>6;
  PORTA &= ~(SEGS_D>>6);
  DDRB  |=  SEGS_B;
  PORTB &= ~SEGS_B;
  DDRD  |=  SEGS_D&0x3f;
  PORTD &= ~(SEGS_D&0X3f);

  DDRB  &= ~0x44;
  PORTB |=  0x44;
  //DDRB  &= ~_BV(6);
  //PORTB |= _BV(6);
  //_delay_us(1);
  //asm volatile("nop\n\tnop\n\tnop\n\tnop\n\t"::);
  //asm volatile("nop\n\tnop\n\tnop\n\tnop\n\t"::);
  //asm volatile("nop\n\tnop\n\tnop\n\tnop\n\tnop\n\t"::);
  //while (!SENSE_BUTT);
  //PORTB &= ~_BV(6);
  while (!SENSE_ALL);
  PORTB &= ~0x44;


  return;
}//if

#endif


//___________ load segments
uint8_t portd = *ioptr++;
uint8_t portb = *ioptr++;
uint8_t porta = portd >> 6;
portd &= 0x3f;

//uint8_t mapb = digit_mapb[pos];
//uint8_t mapd = digit_mapd[pos];
uint8_t mapb = pgm_read_byte(&digit_mapb[pos]);
uint8_t mapd = pgm_read_byte(&digit_mapd[pos]);
DDRA  |= porta;
DDRB  |= portb | mapb;
DDRD  |= portd | mapd;
#ifdef _REVERSE
PORTA |= ~porta;
PORTB |= ~portb & mapb;
PORTD |= ~portd & mapd;
#else
PORTA |= porta;
PORTB |= portb & ~mapb;
PORTD |= portd & ~mapd;
#endif

stays  = *ioptr++;

if (stays && (state & ST_SETUP) && (clicks / TPS_2) &&
  ((pos == (state & ST_SETUP)) ||
  (!pos && !(state & 0x02))))
  stays = 0x08;

pos++;
if (pos >= 4) {
  pos = 0;
  ioptr = output;
}//if

}


//__________________________________________________
void seg2port(uint8_t bcd, uint8_t which) {

if (which & 0x40) {
  //_____________ bcd entry, do 2nd digit 1st, then 1st digit
  which &= 0x0f;
  seg2port(bcd&0x0f, which+1);
  bcd >>= 4;
}//if

uint8_t *pp = output + which * 3;
uint8_t offset = 3;
busy++;

do {
  *pp++ = eeprom_read_byte(&digit2ports[bcd][--offset]);
} while (offset);
busy--;

}

#define HIV _BV(7) //b7
#define VCC _BV(6) //b6
#define SDO _BV(0) //b0

#define SCI _BV(0) //d0
#define SII _BV(5) //d5
#define SDI _BV(6) //d6

#define SCI_PULSE _delay_us(1); PORTD |= SCI; _delay_us(1); PORTD &= ~SCI;
//__________________________________________________
uint8_t hv_cmd(uint8_t *dptr, uint8_t cnt) {
// data format is like write 0_DDDD_DDDD_00
//                      read D_DDDD_DDDx_xx
uint8_t sdo=0x00;
while (cnt) {
  uint8_t sdi = *dptr++;
  uint8_t sii = *dptr++;
  uint8_t cmp=0x80;

  sdo = 0x00;
  PORTD &= ~(SDI|SII);
  SCI_PULSE;
  //sdo = ((PINB&SDO) ? 1 : 0);
  //sdo = ((PINB&SDO) ? 0 : 1);

  // 0x1e92 06
  // 0x62df b0110 0010 1101 1111
  while (cmp) {
   sdo <<= 1;
   //sdo |= ((PINB&SDO) ? 0 : 1);
   //sdo |= ((PINB&SDO) ? 1 : 0);
   if (PINB&SDO) sdo |= 0x01;
   PORTD &= ~(SDI|SII);
   if (cmp&sdi) PORTD |= SDI;
   //else         PORTD &= ~SDI;
   if (cmp&sii) PORTD |= SII;
   //else         PORTD &= ~SII;
   SCI_PULSE;
   //sdo |= (PINB&SDO) ? 1 : 0;
   cmp >>= 1;
  }//while

  PORTD &= ~(SDI|SII);
  SCI_PULSE;
  SCI_PULSE;
  _delay_us(100);
  cnt--;
}//while
//sdo = cnt;

return sdo;
}

uint8_t chip_sig[] = { 0xee, 0xee, 0xee, 0xee, 0x00, 0x00 };

//__________________________________________________
void read_chip(uint8_t release_reset) {

cli();
busy++;

// enter hv mode, everything go low
DDRB  |= (VCC|HIV|SDO);
PORTB &= ~(VCC|SDO);// Vcc and data out off
PORTB |= HIV;  // 12v off
DDRD  |= (SCI|SDI|SII);
PORTD &= ~(SCI|SDI|SII);
//_delay_ms(50);

PORTB |= VCC;  // Vcc on
_delay_us(40);
PORTB &= ~HIV;  // turn on 12v
_delay_us(15);
DDRB  &= ~SDO;  // release SDO
_delay_us(300);

// should be ready to issue commands
// read signature
//
// default fuse settting taken from http://www.engbedded.com/fusecalc/
//
// mcu - id          - factory fuse low-high-extended
// t13 - 1e9007 (07) - 6a-ff
// t25 - 1e9108 (18) - 62-df-ff
// t45 - 1e9206 (26) - 62-df-ff
// t85 - 1e930b (3b) - 62-df-ff
// t24 - 1e910b (1b) - 62-df-ff
// t44 - 1e9207 (27) - 6a-df-ff
// t84 - 1e930c (3c) - 6a-df-ff

// signature  { 0x08, 0x4c, 0xpp, 0x0c,      0x00, 0x68,      0x00, 0x6c
// write fuse { 0x40, 0x4c, val,  0x2c,      0x00, 0x64/0x74, 0x00, 0x6c/0x7c
// read fuse  { 0x04, 0x4c, 0x00, 0x68/0x7a, 0x00, 0x6c/0x7c

uint8_t cmd[] = { 0x08, 0x4c, 0x00, 0x0c, 0x00, 0x68, 0x00, 0x6c, };
uint8_t *pdata = chip_sig;
uint8_t i;

//____________________ read device signature
for (i=0;i<3;i++) {
  cmd[2] = i;
  if (i)
   *pdata++ = hv_cmd(&cmd[2], 3);
  else
   *pdata++ = hv_cmd(cmd, 4);
}//for

uint8_t  id[] = { 0x07, 0x18, 0x26, 0x3b, 0x1b, 0x27, 0x3c, };
uint8_t mcu[] = { 0x13, 0x25, 0x45, 0x85, 0x24, 0x44, 0x84, };

if ((chip_sig[0] == 0x1e) && ((chip_sig[1]&0xf0) == 0x90) &&
  !(chip_sig[2]&0xf0)) {
  chip_sig[1] <<= 4;
  chip_sig[1] |= chip_sig[2];
  /*
  switch (chip_sig[1]) {
   case 0x07: chip_sig[1] = 0x13; break;
   case 0x18: chip_sig[1] = 0x25; break;
   case 0x26: chip_sig[1] = 0x45; break;
   case 0x3b: chip_sig[1] = 0x85; break;
   case 0x1b: chip_sig[1] = 0x24; break;
   case 0x27: chip_sig[1] = 0x44; break;
   case 0x3c: chip_sig[1] = 0x84; break;
   default: chip_sig[1] = 0xee; break;
  }//switch
  chip_sig[0] = 0x00;
  */
  for (i=0;i<7;i++) {
   if (chip_sig[1] == id[i]) {
    chip_sig[0] = i;
    chip_sig[1] = mcu[i];
   }//if
  }//for
  pdata--;
}//if

//____________________ reset fuse
if (release_reset) {
  cmd[0] = 0x40;
  //________________ write fuse low bits
  cmd[3] = 0x2c; cmd[5] = 0x64;
  if (chip_sig[1] == 0x13 || chip_sig[1] == 0x44 || chip_sig[1] == 0x84)
   cmd[2] = 0x6a;
  else
   cmd[2] = 0x62;
  hv_cmd(cmd, 4); _delay_ms(50);
  //________________ write fuse high bits
  cmd[5] = 0x74; cmd[7] = 0x7c;
  if (chip_sig[1] == 0x13)
   cmd[2] = 0xff;
  else
   cmd[2] = 0xdf;
  hv_cmd(cmd, 4); _delay_ms(50);
  //________________ write fuse extended bits
  if (chip_sig[1] != 0x13) {
   cmd[5] = 0x66; cmd[7] = 0x6e;
   cmd[2] = 0x01;
   hv_cmd(cmd, 4); _delay_ms(50);
  }//if
}//if

//____________________ read fuse
cmd[0] = 0x04; cmd[2] = 0x00;

cmd[3] = 0x68; cmd[5] = 0x6c;   // fuse low
*pdata++ = hv_cmd(cmd, 3);

cmd[3] = 0x7a; cmd[5] = 0x7c;   // fuse high
*pdata++ = hv_cmd(cmd, 3);

if (chip_sig[1] != 0x13) {
  cmd[3] = 0x6a; cmd[5] = 0x6e;  // fuse extended
  *pdata++ = hv_cmd(cmd, 3);
}//if


// done, turn things off
PORTB |= HIV;
PORTB &= ~(VCC|SDO);
PORTD &= ~(SCI|SDI|SII);
busy--;
sei();
}

uint8_t menu=0, loc=0;

//__________________________________________________
void main(void) {

TCCR0B |= 0x01;
TIMSK  |= _BV(TOIE0);
TCNT0   = 0x00;

DDRA = PORTA = 0;
DDRD = PORTD = 0;
DDRB   = (VCC|HIV|SDO);
//DDRB   = (VCC|SDO);
PORTB  = HIV;  // 12v off
_delay_ms(50);
read_chip(0);
sei();


while (1) {
  //_____________ "state" bits LBTSRZPP
  //              L - long hold, B - button, T - ticked, S - setup mode,
  //              R - refresh,   Z - buzzer  PP - digit edit position
  //
  //_____________ "menu" bits TxxOxMMM
  //              T   - in toggle mode
  //              O   - option used
  //              MMM - menu id (1-4)

  if (state & ST_TICKED) {
   state &= ~ST_TICKED;
  }//if

  if (state & ST_REFRESH) {
   state &= ~ST_REFRESH;
   dot = _BV(mode);
   if (mode) {
    seg2port(chip_sig[mode*2], 0x40);
   }//if
   else {
    seg2port(POS__, 0);
    seg2port(POS_t, 1);
   }//else
   seg2port(chip_sig[mode*2+1], 0x42);
  }//if

  //_____________________________________ check input
  if (state & ST_BUTTON) { // needs attention
   loc = 0;
   if (state & ST_PRESSED) {
    // normal pressed, rotate display mode
    mode++;
    if (mode >= 3) mode = 0;
   }//if
   else {
    // pressed and held, reset fuse
    mode = 0;
    read_chip(1);
    _delay_us(100);
    read_chip(0);
   }//else
   state &= ~ST_BUTTON;
   state |= ST_REFRESH;
  }//if
}//while

}