/************************************************************
* Processer : MicroChipPIC12C508 *
* Compiler : Hi-TECH PICC8.00 PL2 *
* Writer : Jason Kuo *
* Description : ItCANread/write 93LC46 (64 x 16-bit organization) *
*************************************************************/

static volatile unsigned char RTCC @ 0x01;
static volatile unsigned char TMR0 @ 0x01;
static volatile unsigned char PCL @ 0x02;
static volatile unsigned char STATUS @ 0x03;
static unsigned char FSR @ 0x04;
static volatile unsigned char OSCCAL @ 0x05;
static volatile unsigned char GPIO @ 0x06;

static unsigned char control OPTION @ 0x00;
static volatile unsigned char control TRIS @ 0x06;

/* STATUS bits */
static bit GPWUF @ (unsigned)&STATUS*8+7;
static bit PA0 @ (unsigned)&STATUS*8+5;
static bit TO @ (unsigned)&STATUS*8+4;
static bit PD @ (unsigned)&STATUS*8+3;
static bit ZERO @ (unsigned)&STATUS*8+2;
static bit DC @ (unsigned)&STATUS*8+1;
static bit CARRY @ (unsigned)&STATUS*8+0;

/* OPTION bits */
#define GPWU (1<<7)
#define GPPU (1<<6)
#define T0CS (1<<5)
#define T0SE (1<<4)
#define PSA (1<<3)
#define PS2 (1<<2)
#define PS1 (1<<1)
#define PS0 (1<<0)

/* OSCCAL bits */
static volatile bit CAL3 @ (unsigned)&OSCCAL*8+7;
static volatile bit CAL2 @ (unsigned)&OSCCAL*8+6;
static volatile bit CAL1 @ (unsigned)&OSCCAL*8+5;
static volatile bit CAL0 @ (unsigned)&OSCCAL*8+4;

static volatile bit GP5 @ (unsigned)&GPIO*8+5;
static volatile bit GP4 @ (unsigned)&GPIO*8+4;
static volatile bit GP3 @ (unsigned)&GPIO*8+3;
static volatile bit GP2 @ (unsigned)&GPIO*8+2;
static volatile bit GP1 @ (unsigned)&GPIO*8+1;
static volatile bit GP0 @ (unsigned)&GPIO*8+0;

#define CONFIG_ADDR 0xFFF

/* code protection */
#define MCLREN 0xFFFF // memory clear enable
#define MCLRDIS 0xFFEF // memory clear dISAble

/*watchdog*/
#define WDTEN 0xFFFF // watchdog timer enable
#define WDTDIS 0xFFFB // watchdog timer disable

/* code protection */
#define PROTECT 0xFFF7 // protect the program code
#define UNPROTECT 0xFFFF // do not protect the program code

/*osc configurations*/
#define EXTRC 0xFFFF // external resistor/caPACitor
#define INTRC 0xFFFE // internal
#define XT 0xFFFD // crystal/resonator
#define LP 0xFFFC // low power crystal/resonator

/* 93LC46 I/OPINdefine */
#define CS GP0 //Chip Select
#define CLK GP1 //Serial Data CLOCk
#define DI GP2 //Serial Data Input
#define DO GP4 //Serial Data Output

void Delay(unsigned int counter);
void Pulse(void);
void StartBit(void);
void EWEN(void);
void EWDS(void);
extern void Write93LC46(unsigned char Offset_Addr, unsigned int tx_data);
extern unsigned int Read93LC46(unsigned char Offset_Addr);
void InitPIC(void);

#define CLRWDT() asm(" clrwdt")
#define SLEEP() asm(" sleep")

#define ___mkstr1(x) #x
#define ___mkstr(x) ___mkstr1(x)
#define __CONFIG(x) asm("tpsect config,class=CONFIG,delta=2");
asm("tglobaltconfig_word");
asm("config_word");
asm("tdw "___mkstr(x))

#define __IDLOC(w) asm("tpsect idloc,class=IDLOC,delta=2");
asm("tglobaltidloc_word");
asm("idloc_word");
asm("tirpct__arg," ___mkstr(w));
asm("tdw 0&__arg&h");
asm("tendm")

__CONFIG(MCLRDIS & WDTDIS & EXTRC & PROTECT);

/*----------------------------------------------------
Function : Delay
Input : unsigned int (counter)
Output : None
Description : Delay routine
if counter=1 delay 35us , if counter=10 delay 134us,
if counter=100 delay 1.12ms,
These delay is base on internal 4MHz
------------------------------------------------------*/
void Delay(unsigned int counter)
{
while(counter>0) counter--;
}

/*----------------------------------------------------
Function : Pulse
Input : None
Output : None
Description : Send a pulse (10) to Serial Data Clock(CLK)
------------------------------------------------------*/
void Pulse(void)
{
CLK = 1;
Delay(25);
CLK = 0;
}

/*----------------------------------------------------
Function : StartBit
Input : None
Output : None
Description :
1. SetChipSelect(CS) = 1 (high)
2. Set a Start Bit(1) to Serial Data Input(DI)
------------------------------------------------------*/
void StartBit(void)
{
CS = 1;
DI = 1;
Pulse();
}

/*----------------------------------------------------
Function : EWEN
Input : None
Output : None
Description : ERASE/WRITE Enable
------------------------------------------------------*/
void EWEN(void)
{
unsigned char i,temp;

StartBit(); /* 1 */

temp = 0x80; /* 0011xxxx ,(opcode:00, Address:11xxxx) */
for(i=0; i<8; i++) {
if(0x30 & temp)
DI = 1;
else
DI = 0;
Pulse();
temp >>= 1;
}

CS = 0;
}

/*----------------------------------------------------
Function : EWDS
Input : None
Output : None
Description : ERASE/WRITE DISAble
------------------------------------------------------*/
void EWDS(void)
{
unsigned char i;

StartBit(); /* 1 */

DI = 0; /* 0000xxxx, (opcode:00, Address:00xxxx) */
for(i=0; i<8; i++)
Pulse();

CS = 0;
}

/*----------------------------------------------------
Function : Write93LC46
Input : unsigned char Offset Address, unsigned int tx_data
Output : None
Description : Write 16bits data in to 93LC46 Offset Address
------------------------------------------------------*/
void Write93LC46(unsigned char Offset_Addr, unsigned int tx_data)
{
unsigned char Addr, i;
unsigned int temp;

EWEN();

StartBit(); /* 1 */
Offset_Addr=Offset_Addr&0x3F; /* 6bits address */
Addr = Offset_Addr + 0x40; /* 01AAAAAA ,(opcode:01, address:AAAAAA) */
temp = 0x0080;
for(i=0; i<8; i++) {
if(Addr & temp)
DI = 1;
else
DI = 0;
Pulse();
temp >>= 1;
}

temp = 0x8000; /* DDDDDDDDDDDDDDDD(16bits data)*/
for(i=0; i<16; i++) {
if(tx_data & temp)
DI = 1;
else
DI = 0;
Pulse();
temp >>= 1;
}
CS = 0;