RTC take two

I thought I would start a new thread as the other one based on the RTC giving strange readings seems to be something with the BDC conversions.

I have tried the following to set the time / date to a DS1307 RTC chip within my main section of code.

Code:

---

gosub write_1307
read_1307:                          ' Read time Secs,Mins,Hours,Day,Date,Month,Year,Control
I2CREAD SDA,SCL,$D1,$00,[STR DB0\8] ' Read 8 bytes from DS1307

lcdout $fe,1,"Time=",hex2 DB0[2],":",hex2 DB0[1],":",hex2 DB0[0]    'bit 0=sec, bit 1=min, bit 2=hrs
lcdout $fe,$c0,"Date=",hex2 DB0[4],":",hex2 DB0[5],":",hex2 db0[6]  'bit 4=day, bit 5=month, bit 6=year
goto read_1307


********************************************

Write_1307:                          ' format: Sec Min Hr Day D M Y Control .  EG to Set time & date to 19:00:00  14th Feb 2010
I2CWRITE SDA,SCL,$D0,$00,[$00,$00,$19,$7,$14,$2,$10,$90] ' Write to DS1307
pause 10
RETURN                              '

---

This works a treat - however I want to be able to set the values in the I2CWRITE string and have a routine that places the decimal values of 00 to 23 for hours and 00-59 for minutes into two variables SetHour and SetMin

Code:

---

time:

LCDOUT $FE,1
LCDOUT $FE,2,"Set Time"
   
inp3:

IF H_butt = 0 THEN GOSUB IncHours
IF M_butt = 0 THEN GOSUB IncMinutes
    SetHour=Hours
    SetMin=Minutes
 
LCDOUT $FE,$C0,#SetHour DIG 1,#SetHour DIG 0,":",#SetMin DIG 1,#SetMin DIG 0
pause 200
If S_butt = 0 then
pause 250
goto savetime
endif
goto inp3

---

From what I understand PBO has a command / modifier IHEX, but I'm not sure on how to use it. Basically what I would like to do is take those decimal values in the two variables sethour and setmin and convert them to HEX and then place it to the relevant byte that gets written to the RTC... something like

Code:

---

DB0[2] = IHEX sethour
DB0[1] = IHEX setmin

---

The current version uses a BCD conversion... but this is where I think the issues I had detailed in the previous thread lay, - is there a simple way that will convert the values and write them to the relevant bytes for the 1307 ?

second is variable value which displays sec digits when second is displayed as hex number.

second = (sec >> 1)*16 + (sec & $F) to convert time number sec to hex value second that displays time number, I think.

I made a typo error above

should be --

second = (sec >> 4)*16 + (sec & $F)

Many thanks

And if you want to add to time values from DS1307 then convert to decimal before addition --

sec = (RTCsec >> 4)*10 + (RTCsec & $F)