Well… in case anyone was wondering… after much trial and error… it appears to be working. Time will tell (pun sortof intended).
Here is the code that seems to work.
**********************************************************************************************************
#include "DS1302 RTC.h"
sbit ACC0 = ACC^0;
sbit ACC7 = ACC^7;
sbit CE_1302 = P2^4; // 1302 CE bit
sbit SCLK_1302 = P2^1; // 1302 Strobe Clock bit
sbit IO_1302 = P2^0; // 1302 IO bit
#define BURST_READ_1302 0xbf
#define BURST_WRITE_1302 0xbe
#define SECONDS_READ_1302 0x81
#define SECONDS_WRITE_1302 0x80
#define HOURS_READ_1302 0x85
#define HOURS_WRITE_1302 0x84
#define WP_WRITE_1302 0x8e
static INT8U read_byte(void)
{
INT8U i, dat;
dat = 0;
for (i = 0; i < 8; i++)
{
dat = dat >> 1;
if (IO_1302 == 1)
dat = dat | 0x80;
SCLK_1302 = 1;
SCLK_1302 = 0;
}
return dat;
}
static void write_byte(INT8U byte)
{
INT8U i, dat;
dat = byte;
SCLK_1302 = 0;
for (i = 0; i < 8; i++)
{
IO_1302 = dat & 0x01;
SCLK_1302 = 1;
SCLK_1302 = 0;
dat = dat >> 1;
}
}
Time_Date get_time_1302(void)
{
Time_Date dt;
CE_1302 = 0;
SCLK_1302 = 0;
CE_1302 = 1;
write_byte(BURST_READ_1302);
dt.second = read_byte();
dt.second = (((dt.second & 0x70) >> 4) * 10) + (dt.second & 0x0f);
dt.minute = read_byte();
dt.minute = (((dt.minute & 0x70) >> 4) * 10) + (dt.minute & 0x0f);
dt.hour = read_byte();
dt.hour = (((dt.hour & 0x70) >> 4) * 10) + (dt.hour & 0x0f);
dt.date = read_byte();
dt.date = (((dt.date & 0x70) >> 4) * 10) + (dt.date & 0x0f);
dt.month = read_byte();
dt.month = (((dt.month & 0x70) >> 4) * 10) + (dt.month & 0x0f);
dt.day = read_byte();
dt.year = read_byte();
dt.year = (((dt.year & 0xf0) >> 4) * 10) + (dt.year & 0x0f);
SCLK_1302 = 1;
CE_1302 = 0;
return dt;
}
void set_time_1302(Time_Date dt)
{
CE_1302 = 0;
SCLK_1302 = 0;
CE_1302 = 1;
write_byte(BURST_WRITE_1302);
write_byte((((dt.second / 10) << 4) + (dt.second % 10)) & 0x7f);
write_byte(((dt.minute / 10) << 4) + (dt.minute % 10));
write_byte((((dt.hour / 10) << 4) + (dt.hour % 10)) & 0x3f);
write_byte(((dt.date / 10) << 4) + (dt.date % 10));
write_byte(((dt.month / 10) << 4) + (dt.month % 10));
write_byte(dt.day);
write_byte(((dt.year / 10) << 4) + (dt.year % 10));
write_byte(0);
SCLK_1302 = 1;
CE_1302 = 0;
}
void init_1302(void)
{
INT8U byte_second;
INT8U byte_hour;
//Disable Clock Halt
CE_1302 = 0;
SCLK_1302 = 0;
CE_1302 = 1;
write_byte(SECONDS_READ_1302);
byte_second = read_byte();
SCLK_1302 = 0;
write_byte(SECONDS_WRITE_1302);
write_byte(byte_second & 0x7f);
SCLK_1302 = 1;
//Set to 24 hour mode
write_byte(HOURS_READ_1302);
byte_hour = read_byte();
SCLK_1302 = 0;
write_byte(HOURS_WRITE_1302);
write_byte(byte_hour & 0x3f);
SCLK_1302 = 0;
//Disable Write Protection
write_byte(WP_WRITE_1302);
write_byte(0);
SCLK_1302 = 0;
CE_1302 = 0;
}
**********************************************************************************************************