Real Time Clock 1302

Hi guys

Found this example on the site but could not find how the tris bits are set for for the data direction from out to in the code , is it required , if not how did the data pin change direction for the read ( shiftin)

cheers

sheldon

Code:

' An example routines to use the DS1302 timer chip ' based on code provided by Omer Yildiz, Copyright (c) 2006 [2005] ' http://www.picbasic.co.uk/forum/showthread.php?t=423 ' This code uses a supercap at VCC1 to provide power when VCC2 is interupted ' Set initial time manually in clockinit ' Then reprogramme with convertTime and setClock commented out DEFINE LOADER_USED 1 'enable bootloader DEFINE osc 20 'defines for debug INCLUDE "modedefs.bas" 'set-up debug serial DEFINE DEBUG_REG PORTB ' Set Debug pin port DEFINE DEBUG_BIT 6 ' Set Debug pin bit DEFINE DEBUG_BAUD 9600 ' Set Debug baud rate DEFINE DEBUG_MODE 1 ' Set Debug mode: 0 = true, 1 = inverted LED VAR PORTC.5 'clock pin definitions-------------------------------------------- timer_clk var portb.3 ' DS1302 Clock Pin timer_dq var portb.2 ' DS1302 Data Pin timer_rst var portb.1 ' DS1302 Reset Pin 'decimal variables for setting up time--------------- second var byte minute var byte hour var byte day var byte month var byte year var byte 'hex variables for actual time display-------------- secondx Var byte minutex var byte hourx var byte dayx var byte monthx var byte yearx var byte RTC var byte 'Write Commands For DS1302 -------------------------- writectrl con $8E ' Control byte writechrg CON $91 ' Write trickle charge tricklereg CON $A0 ' Enable trickle charge for supercap writeram con $80 ' Write to RAM writeprotect con $00 ' Write-protect DS1302 writesec con $80 ' Write seconds writemin con $82 ' Write minutes writehour con $84 ' Write hour writedate con $86 ' Write date writemonth con $88 ' Write month writeyear con $8C ' Write year 'Read Commands For DS1302 ------------------------- readsec con $81 ' Read seconds from DS1302 readmin con $83 ' Read minutes from DS1302 readhour con $85 ' Read hours from DS1302 readdate con $87 ' Read date from DS1302 readyear con $8D ' Read year from DS1302 readmonth con $89 ' Read month from DS1302 'Time Variables ------------------------------ mem var byte ' Temporary data holder outbyte var byte ' Second byte to ds1302 reg_adr var byte ' First byte to DS1302 decx var byte ' A swap variable HIGH LED PAUSE 1000 LOW LED 'Initial Settings For Ports ------------------------ clockInit: DEBUG "DS1302 timer with trickle charge",10,13 ' set intial time and date here second = 20 minute = 14 hour = 12 day = 10 month = 9 year = 7 low timer_rst ' Set reset pin low low timer_clk ' Set clock pin low ' This enables the trickle charger GOSUB setTrickleCharge ' These two should be commented out after initialising the PIC ' with the time date above 'GOSUB convertTime 'GOSUB setClock GOTO loop 'Read time at 5 secind intervals------------------------- loop: call readclk ' go read DS1302 pause 5000 goto loop 'Time Commands Subroutines -------------------------- readclk: reg_adr = readsec 'Read seconds gosub timerRead second = mem reg_adr = readmin 'Read minutes gosub timerRead minutex = mem reg_adr = readhour 'Read Hours gosub timerRead hourx = mem reg_adr = readyear 'Read Year gosub timerRead yearx = mem reg_adr = readdate 'Read Date gosub timerRead dayx = mem reg_adr = readmonth 'Read Month gosub timerRead monthx = mem DEBUG HEX hourx,":",HEX minutex,":",HEX second," ",HEX dayx,"/",HEX monthx,"/",HEX yearx,10,13 return setTrickleCharge: reg_adr = writectrl ' Set to control byte outbyte = writeprotect ' Set turn off protection gosub timerWrite ' Send both bytes reg_adr = writechrg outbyte = tricklereg gosub timerWrite reg_adr = writectrl outbyte = writeprotect gosub timerWrite RETURN setClock: reg_adr = writectrl ' Set to control byte outbyte = writeprotect ' Set turn off protection gosub timerWrite ' Send both bytes reg_adr = writesec ' Set to write seconds register outbyte = secondx ' Set to write 00 to seconds register in HEX format gosub timerWrite reg_adr = writemin outbyte = minutex 'Our minutex and others with x (except for monthx) are now in HEX format. gosub timerWrite reg_adr = writehour outbyte = hourx gosub timerWrite reg_adr = writedate outbyte = dayx gosub timerWrite reg_adr = writemonth outbyte = monthx gosub timerWrite reg_adr = writeyear outbyte = yearx gosub timerWrite reg_adr = writectrl outbyte = writeprotect gosub timerWrite RETURN timerRead: mem = reg_adr ' Set mem variable to reg_adr contents high timer_rst ' Activate the DS1302 shiftout timer_dq,timer_clk,0, [mem] ' Send control byte shiftin timer_dq,timer_clk,1, [mem] ' Retrieve data in from the DS1302 low timer_rst ' Deactivate DS1302 return timerWrite: mem = reg_adr ' Set mem variable to reg_adr contents high timer_rst ' Activate the DS1302 shiftout timer_dq,timer_clk,0, [mem] ' Send control byte mem = outbyte ' Set mem variable to outbyte contents shiftout timer_dq,timer_clk,0, [mem] ' Send data stored in mem variable to DS1302 low timer_rst ' Deactivate DS1302 return 'Convert initial set up times to hex--------------------------------- convertTime: pause 100 call chkLeap pause 20 decx=year gosub convertion yearx=rtc pause 100 decx=month gosub convertion monthx=rtc pause 100 decx=day gosub convertion dayx=rtc pause 100 decx=hour gosub convertion hourx=rtc pause 100 decx=minute gosub convertion minutex=rtc pause 100 decx=second gosub convertion secondx=rtc RETURN 'Convert DEC to HEX convertion: RTC=decx DIG 1 RTC=RTC<<4 RTC=RTC+decx DIG 0 return 'Check for leap year chkLeap: if year=8 or year=12 or year=16 or year=20 Then write 2,29 'Years with Feb=29 days (for 50 yrs.) pause 20 else write 2, 28 pause 20 endif return END

Re: Real Time Clock 1302

Hello Sheldon,

SHIFTIN and SHIFTOUT take care of setting the data directions on their own; PBP takes care of it. I checked some code where I have used these commands and (for no particular reason) initialized both the data and clock pins as outputs.

Best Regards,
Paul

Re: Real Time Clock 1302

ah cool , i thought as much , but i looked for such detail in the PB3 help file for shiftin , shiftout but there is no mention of that fact , that i could see , maybe in the manual somewhere

Re: Real Time Clock 1302

Couldn't see anything in the manual for SHIFTIN.

(PBP 3.0 rev. Nov 28 2011)

Robert

Re: Real Time Clock 1302

thanks robert ,

i thought i look hard and long at the online help in PB3 for the info before i posted , its clear its been a feature for some time of shiftin , shiftout , but not mentioned ,
up until now i have only had pins for shiftin/ out that were defined for in or out not one pin that was used for both