TRIS setting for the DS1302

[Dennis]

Hi all

I wonder if someone could please tell me what the TRIS settings should be to work with the DS1302.
I have been checking out code examples through the forums and have even tried a few. I am still not sure of what the TRIS settings should be for my PIC to interact with the DS1302.

So given the following for example :


RST var PORTA.2
IO var PORTC.1
SCLK var PORTC.3

Kind regards

Dennis

[mackrackit]

I2CREAD/WRITE takes care of that for you.

[Dennis]

@Dave thanks a million for that reply, it has sent me hurtling off to understand I2Cread and I2Cwrite.

Can anyone confirm the use of a DS1302 with I2Cread/WRITE or should I rather be using the SHIFTIN/OUT displayed in most of the forum threads regarding the DS1302.

I really would appreciate some help regarding the DS1302 and a kickstart of sorts.

Kind regards

Dennis

[Art]

I suspect you use serial (SHIFTOUT) with the 1302.
I know you use I2C with the 1307.

[Art]

From CocaColaKid:




'-------------------------- Clock Variables ---------------------------------

rst var portb.2 ' DS1302 Reset Pin
clk var portb.1 ' DS1302 Clock Pin
dq var portb.0 ' DS1302 Data Pin

'----------------------- Write Commands For DS1302 --------------------------

writectrl con $8E ' Control byte
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
date var byte ' Date variable
ss var byte ' Seconds variable
mm var byte ' Minutes varibale
hh var byte ' Hours variable
mo var byte ' Month variable
yr var byte ' Year variable

'------------------------ Initial Settings For Ports ------------------------

low rst ' Set reset pin low
low clk ' Set clock pin low

trisb = 0
trisa = 0

'----------------------- Set Initial Time Variables -------------------------

if portb.4 = 1 then START ' Set inital clock start up if jumper is present
reg_adr = writectrl ' Set to control byte
outbyte = writeprotect ' Set turn off protection
gosub w_out ' Send both bytes
reg_adr = writesec ' Set to write seconds register
outbyte = $00 ' Set to write 00 to seconds register
gosub w_out
reg_adr = writemin
outbyte = $30
gosub w_out
reg_adr = writehour
outbyte = $00
gosub w_out
reg_adr = writedate
outbyte = $01
gosub w_out
reg_adr = writemonth
outbyte = $01
gosub w_out
reg_adr = writeyear
outbyte = $00
gosub w_out
reg_adr = writectrl
outbyte = writeprotect
gosub w_out

start:
reg_adr = readsec ' Read seconds
gosub w_in
ss = mem
reg_adr = readmin ' Read minutes
gosub w_in
mm = mem
reg_adr = readhour ' Read Hours
gosub w_in
hh = mem
reg_adr = readyear ' Read Year
gosub w_in
yr = mem
reg_adr = readdate ' Read Date
gosub w_in
date = mem
reg_adr = readmonth ' Read Month
gosub w_in
mo = mem
lcdout $fe,1,"TIME:",HEX2 hh,":",HEX2 mm,":",HEX2 ss
pause 500
goto start

'----------------------- Time Commands Subroutines --------------------------

w_in:
mem = reg_adr ' Set mem variable to reg_adr contents
high rst ' Activate the DS1302
shiftout dq,clk,0, [mem] ' Send control byte
shiftin dq,clk,1, [mem] ' Retrieve data in from the DS1302
low rst ' Deactivate DS1302
return

w_out:
mem = reg_adr ' Set mem variable to reg_adr contents
high rst ' Activate the DS1302
shiftout dq,clk,0, [mem] ' Send control byte
mem = outbyte ' Set mem variable to outbyte contents
shiftout dq,clk,0, [mem] ' Send data stored in mem variable to DS1302
low rst ' Deactivate DS1302
return



I have used an assembler routine with the 1302 (in a basic program) and it works:




#define SPI_CLK PORTA,1 ; spi bus clock line
#define SPI_MOSI PORTA,2 ; spi master out data
#define SPI_MISO PORTA,3 ; spi slave input data
#define SPI_CE PORTA,4 ; chip enable for SPI device

SCRATCH equ 0x40 ; 1 by general purpose scratchpad
TMP equ 0x41 ; temp register
TMP2 equ 0x42 ; temp register
COUNT equ 0x43
;YRS equ 0x44
;MON equ 0x45
;DOW equ 0x46
;DAYS equ 0x47
;HRS equ 0x48
;MINS equ 0x49
;SECS equ 0x4a

;user_bits equ 0x2C ;
;save_w equ 0x38
;save_status equ 0x39





;---- Read RTC into W (assume address already sent) ----
;---- assumes CE is asserted ----
read_RTC:
movlw 08h ;Send 8 bits
movwf COUNT

SPI_read_loop:
rlf TMP, 1

bcf SPI_CLK ; clock data out

bcf TMP, 0 ; assume data out is low
btfsc SPI_MISO
bsf TMP, 0 ; if data out=1, set bit

bsf SPI_CLK
decfsz COUNT, 1
goto SPI_read_loop

movf TMP, W

return

;--- Write the byte in W to RTC ---
;---- assumes CE is asserted ----
write_RTC:
movwf TMP ;Save the data
;
;--- Do a SPI bus write of byte in 'TMP' ---
;
SPI_write:
movlw 08h ;Send 8 bits
movwf COUNT

SPI_w_loop:
bcf SPI_CLK

bcf SPI_MOSI ; assume data out is low
btfsc TMP, 7
bsf SPI_MOSI ; if data out=1, set bit

SPI_w_cont:
rlf TMP, 1
bsf SPI_CLK ; clock it in
decfsz COUNT, 1
goto SPI_w_loop

return


Cheers, Art.

[Dennis]

@ Art
Thanks a million for the reply.
I had already checked out code by Cocacolakid as well as Sayzer and quite a few others, as well as Melanie's example MN1307.txt, with little or no success.
The code from Cocacolakid uses the shiftin/out method not so ?
This is the reason why I asked about the TRIS statement.
Check the first few lines of Cocolakid's code:


'-------------------------- Clock Variables ---------------------------------

rst var portb.2 ' DS1302 Reset Pin
clk var portb.1 ' DS1302 Clock Pin
dq var portb.0 ' DS1302 Data Pin

What should the TRIS statement be ? Or is this handled by the SHIFTIN/OUT statement ?
Later on in his code there is :


'------------------------ Initial Settings For Ports ------------------------

low rst ' Set reset pin low
low clk ' Set clock pin low

trisb = 0
trisa = 0


The forum is scattered with many examples for DS1302 and DS1307 and various timers, clocks elapsed timers, olympic clocks and there are even examples for the various LABX boards,even some methods to use a PIC as a timer with accuracy much like that of a DS1302/7 depending on the crystal you choose.

With the wealth of information here it starts becoming rather difficult to figure out which clock chip is a good selection and why.

From what I can see (and I may well be wrong),
if you're using the DS1302 then you should use a shiftin/out method and
if you're using a DS1307 you should use the I2C method.

I am trying to build a very simple alarm clock which triggers on a matching date and time. It will also be used as a datalogger for logging the time and duration of power failures for my generator since we have many power failures in our area at some really odd times.

Your info has been most useful in starting to figure out some parts of this puzzle.

Any more info you or anyone else would also be most welcome.

Kind regards

Dennis

[Dennis]

@Art

I decided to give Cocacolakid's code a whirl,sadly time stand still :-( display is stuck at 00:00:80
I think it's because of the if statement here:

if portb.4 = 1 then START ' Set initial clock start up if jumper is present
So after removing it since I have no jumper there and re-programming the PIC.
The display shows:
00:30:00 and time stands still :-(
Here's the code I am using :


'
'using pic18f4520
'
'Ocsillator selections here
OSCCON = $70 'Int CLK 8MHz
OSCTUNE.6 = 1 'PLL 4x
ADCON1= %00001111 '$0F = disable A/D converter
cmcon = 7
INTCON2.7 = 0 'switch pull-ups ON
'END of oscillator selections
'timer/oscillator defines
DEFINE OSC 32 '4x 8MHz
'END of timer/oscillator defines

'Port IO directions and presets for port pins begin here
'TRISX = %76543210 << tris bit order numbering
'TRISA = %11111111 'All pins are outputs
'Define port pins as inputs and outputs ...
'example only - TRISB = %00001111 ;Make 'B4-B7 outputs, B0-B3 inputs
TRISA = %00000000 'assigned to LCD
TRISB = %11111111 'for 4x4 keypad all input
TRISC = %10000000
TRISD = %00000000
TRISE.0 = 0
TRISE.1 = 0
TRISE.2 = 0
'End of Port IO directions and presets for port pins begin here



'LCD defines begin here
DEFINE LCD_BITS 4 'defines the number of data interface lines (4 or 8)
DEFINE LCD_DREG PORTD 'defines the port where data lines are connected to
DEFINE LCD_DBIT 4 'defines the position of data lines for 4-bit interface (0 or 4)
DEFINE LCD_RSREG PORTD 'defines the port where RS line is connected to
DEFINE LCD_RSBIT 2 'defines the pin where RS line is connected to
DEFINE LCD_EREG PORTD 'defines the port where E line is connected to
DEFINE LCD_EBIT 3 'defines the pin where E line is connected
'DEFINE LCD_RWREG 0 'defines the port where R/W line is connected to (set to 0 if not used)
'DEFINE LCD_RWBIT 0 'defines the pin where R/W line is connected to (set to 0 if not used)
DEFINE LCD_COMMANDUS 2000 'defines the delay after LCDOUT statement
DEFINE LCD_DATAUS 200 'delay in micro seconds
'END of LCD DEFINES

'includes begin here
INCLUDE "modedefs.bas"
include "c:\pbp\samples\keypad.bas"
'end of includes

DEFINE HSER_RCSTA 90h ' Enable serial port & continuous receive
DEFINE HSER_TXSTA 20h ' Enable transmit, BRGH = 0
DEFINE HSER_SPBRG 207 ' 2400 Baud @ 32MHz, 0.17%
DEFINE HSER_CLROERR 1 ' Clear overflow automatically

'-------------------------- Clock Variables ---------------------------------


clk var portC.3 ' DS1302 Clock Pin
dq var portC.4 ' DS1302 Data Pin
rst var portD.1 ' DS1302 Reset Pin



'----------------------- Write Commands For DS1302 --------------------------

writectrl con $8E ' Control byte
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
date var byte ' Date variable
ss var byte ' Seconds variable
mm var byte ' Minutes varibale
hh var byte ' Hours variable
mo var byte ' Month variable
yr var byte ' Year variable

'------------------------ Initial Settings For Ports ------------------------

low rst ' Set reset pin low
low clk ' Set clock pin low

'----------------------- Set Initial Time Variables -------------------------

'if portb.4 = 1 then START ' Set inital clock start up if jumper is present

reg_adr = writectrl ' Set to control byte
outbyte = writeprotect ' Set turn off protection
gosub w_out ' Send both bytes
reg_adr = writesec ' Set to write seconds register
outbyte = $00 ' Set to write 00 to seconds register
gosub w_out
reg_adr = writemin
outbyte = $30
gosub w_out
reg_adr = writehour
outbyte = $00
gosub w_out
reg_adr = writedate
outbyte = $01
gosub w_out
reg_adr = writemonth
outbyte = $01
gosub w_out
reg_adr = writeyear
outbyte = $00
gosub w_out
reg_adr = writectrl
outbyte = writeprotect
gosub w_out

start:
reg_adr = readsec ' Read seconds
gosub w_in
ss = mem
reg_adr = readmin ' Read minutes
gosub w_in
mm = mem
reg_adr = readhour ' Read Hours
gosub w_in
hh = mem
reg_adr = readyear ' Read Year
gosub w_in
yr = mem
reg_adr = readdate ' Read Date
gosub w_in
date = mem
reg_adr = readmonth ' Read Month
gosub w_in
mo = mem
lcdout $fe,1,"TIME:",HEX2 hh,":",HEX2 mm,":",HEX2 ss
pause 500
goto start

'----------------------- Time Commands Subroutines --------------------------

w_in:
mem = reg_adr ' Set mem variable to reg_adr contents
high rst ' Activate the DS1302
shiftout dq,clk,0, [mem] ' Send control byte
shiftin dq,clk,1, [mem] ' Retrieve data in from the DS1302
low rst ' Deactivate DS1302
return

w_out:
mem = reg_adr ' Set mem variable to reg_adr contents
high rst ' Activate the DS1302
shiftout dq,clk,0, [mem] ' Send control byte
mem = outbyte ' Set mem variable to outbyte contents
shiftout dq,clk,0, [mem] ' Send data stored in mem variable to DS1302
low rst ' Deactivate DS1302
return

I have attached my circuit diagram too ...perhaps that's where the mess-up is ?

Will try asm code as well and feedback

Also going to source a DS1307 and DS1337C tomorrow and later this week, will post an update asap.

Kind regards

Dennis

[malc-c]

Also going to source a DS1307 and DS1337C tomorrow and later this week, will post an update asap.

Kind regards

Dennis

Dennis,

I'm using a DS1307, well one of MicroElektronica's RTC modules for the EasyPIC5 board and have the following example displaying time and date on a 16 x 2 LCD. I've only included the code for the RTC as there are loads of examples for hooking up an LCD.



SDA var PORTC.1 ' RTC data
SCL var PORTC.0 ' RTC clock

TRISC= %00000011
DB0 var byte[8]
CMCON = %00000111 ' Comparators = off
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
end

Write_1307: ' Set time & date to 19:00:00 14th Feb 201
I2CWRITE SDA,SCL,$D0,$00,[$00,$00,$19,$7,$14,$2,$10,$90] ' Write to DS1307
pause 10
RETURN ' Sec Min Hr Day D M Y Control


I've had this running for some time in testing, and seems quite stable. One thing that needs developing further is a means of entering the date and time via push buttons or some other means, but at least you should be able to see the basic operation

[Byte_Butcher]

you don't need to read the registers of the DS1302 individually. You can grab the whole contents of the time register in one shot using "burst mode".



high rst ' Ready for transfer
Shiftout IO, SCLK, LSBFIRST, [$bf] ' Read all 8 RTC registers in burst mode
Shiftin IO, SCLK, LSBPRE, [rtcsec, rtcmin, rtchr, rtcdate, rtcmonth, rtcday, rtcyear, rtccontrol]
low rst ' Reset RTC

That should load all the time info into your variables, rtcsec, rtcmin, rtchr, rtcdate, rtcmonth, rtcday, rtcyear, rtccontrol


steve

[Dennis]

@Steve :-)

Thanks for that info , actually saw your posts as I was sifting through the forum posts on DS1307 and DS1302 and I2Cread and I2CWrite , in fact I even tried it with my DS1302 (of course it didn't work since I2C is not what should be used for the DS1302) :-)
Will try get something going for the DS1302 using that stub you posted and see what comes of it and will definitely give the DS1307 stubs a good bash when I get my DS1307.

Regarding this line though ...

Write_1307: ' Set time & date to 19:00:00 14th Feb 201, do you think they made much of a fuss about Valentines day back then ?
I also wonder if this isn't how the Rosetta stone came about, some ancients trying to scribe stuff into a rock...it's just like us really .. we are making rock (Silicon) do some really wild things.
Even wirelessly rock to rock ...INSANE hey ?
Now to explain those cave paintings !

Chat soon

Kind regards

Dennis

[malc-c]

Regarding this line though ...

Write_1307: ' Set time & date to 19:00:00 14th Feb 201, do you think they made much of a fuss about Valentines day back then ?
I also wonder if this isn't how the Rosetta stone came about, some ancients trying to scribe stuff into a rock...it's just like us really .. we are making rock (Silicon) do some really wild things.
Even wirelessly rock to rock ...INSANE hey ?
Now to explain those cave paintings !

Chat soon

Kind regards

Dennis

LOL - must check my posts before uploading :)

[Dennis]

@Steve ..apologies .. was actually asking Malc-c about valentines day :-)
@ Steve , regarding these lines :

high rst ' Ready for transfer
Shiftout IO, SCLK, LSBFIRST, [$bf] ' Read all 8 RTC registers in burst mode
Shiftin IO, SCLK, LSBPRE, [rtcsec, rtcmin, rtchr, rtcdate, rtcmonth, rtcday, rtcyear, rtccontrol]
low rst ' Reset RTC

I understand these
LSBFIRST ' MODE 0 - Shift data out lowest bit first. Clock idles low.
LSBPRE ' MODE 0 - Shift data in lowest bit first,Read data before sending clock. Clock idles low.
But what is the [$bf] ?

@Malc-c --to err is human :-)

Kind regards

Dennis

[Byte_Butcher]

$bf is the register address for clock burst mode read I believe.

Do a search for $bf in the ds1302 data sheet.


steve

[Dennis]

Yes had just checked data sheet just after I posted !
$bf is for burst mode :-)

Thanks to all who replied .. this is making a whole lot more sense now :-)

Kind regards
Dennis

[Dennis]

@ Steve ...
Do you have a snippet for the write in burst mode so one can set the clock ?

Kind regards

Dennis

[Byte_Butcher]

Sure, this should do it:


settime: ' Subroutine to write time to RTC
RST = 1 ' Ready for transfer
Shiftout IO, SCLK, LSBFIRST, [$8e, 0] ' Enable write
RST = 0 ' Reset RTC
RST = 1 ' Ready for transfer
' Write all 8 RTC registers in burst mode
Shiftout IO, SCLK, LSBFIRST, [$be, rtcsec, rtcmin, rtchr, rtcdate, rtcmonth, rtcday, rtcyear, 0]
rst = 0
Return

steve

[Dennis]

@Steve

My code before you replied ...

setclk:
high rst ' Ready for transfer RTC pin must go high
Shiftout ds_data, ds_clk, LSBFIRST, [$bf] ' send burst mode control $bf to read all 8 RTC registers in burst mode
Shiftout ds_data, ds_clk, LSBFIRST, [rtcsec, rtcmin, rtchr, rtcdate, rtcmonth, rtcday, rtcyear, rtccontrol] send the data
low rst ' Reset RTC reset pin

As you can see I was totally off the mark with the $bf , $be setting !

Ok but I have read in a lot of posts regarding the DS1302 and BCD conversion ..does this still apply ?

Kind regards
Dennis

[Dennis]

Hi all

I have been battling for over a week now trying to get the DS1302 clock chip working.

I think I finally have the format and code sorted , only problem is that my clock never ticks :-( in other words the time never changes!

Please could somebody either take a look at my code or advise me what I should check next.
I'm sure it is really something small or silly that I have overlooked.

Kind regards

Dennis


'device 18F4520
'DS1302 test
'
'

'Ocsillator selections here
OSCCON = $70 'Int CLK 8MHz
OSCTUNE.6 = 1 'PLL 4x
ADCON1= %00001111 '$0F = disable A/D converter
cmcon = 7
INTCON2.7 = 0 'switch pull-ups ON
'END of oscillator selections
'timer/oscillator defines
DEFINE OSC 32 '4x 8MHz
'END of timer/oscillator defines
'
'
'Port IO directions and presets for port pins begin here
'TRISX = %76543210 << tris bit order numbering
'TRISA = %11111111 'All pins are outputs
'// Define port pins as inputs and outputs ...
TRISA = %00000000 'example only - TRISB = %00001111 ;Make B4-B7 outputs, B0-B3 inputs,
TRISB = %11111111 'for 4x4 keypad all input
TRISC = %10000000
TRISD = %00000000
TRISE.0 = 0
TRISE.1 = 0
TRISE.2 = 0
'End of Port IO directions and presets for port pins begin here
'
'
'
'LCD defines begin here
DEFINE LCD_BITS 4 'defines the number of data interface lines (4 or 8)
DEFINE LCD_DREG PORTD 'defines the port where data lines are connected to
DEFINE LCD_DBIT 4 'defines the position of data lines for 4-bit interface (0 or 4)
DEFINE LCD_RSREG PORTD 'defines the port where RS line is connected to
DEFINE LCD_RSBIT 2 'defines the pin where RS line is connected to
DEFINE LCD_EREG PORTD 'defines the port where E line is connected to
DEFINE LCD_EBIT 3 'defines the pin where E line is connected
'DEFINE LCD_RWREG 0 'defines the port where R/W line is connected to (set to 0 if not used)
'DEFINE LCD_RWBIT 0 'defines the pin where R/W line is connected to (set to 0 if not used)
DEFINE LCD_COMMANDUS 2000 'defines the delay after LCDOUT statement
DEFINE LCD_DATAUS 200 'delay in micro seconds
'END of LCD DEFINES
'
'includes begin here
INCLUDE "modedefs.bas"
'end of includes
'
'HSER defines
DEFINE HSER_RCSTA 90h ' Enable serial port & continuous receive
DEFINE HSER_TXSTA 20h ' Enable transmit, BRGH = 0
DEFINE HSER_SPBRG 207 ' 2400 Baud @ 32MHz, 0.17%
DEFINE HSER_CLROERR 1 ' Clear overflow automatically
'HSER defines begin here

'-------------------------- Clock Variables ---------------------------------


'SCLK var portC.3 ' DS1302 Clock Pin 7
'IO var portC.4 ' DS1302 Data Pin 6
'rst var portD.1 ' DS1302 Reset Pin 5


'pins
RST var PORTA.0 'DS1302 PIN 5
IO var PORTA.1 'DS1302 PIN 6
SCLK var PORTA.2 'DS1302 PIN 7

'variables
rtcyear var byte
rtcday var byte
rtcmonth var byte
rtcdate var byte
rtchr var byte
rtcmin var byte
rtcsec var byte
rtccontrol var byte


Main:
Low RST ' Reset DS1302 RTC
Low SCLK 'pull SCLK line LOW
' clock Set 16:45:00 04/14/08
rtcyear = $08
rtcday = $06
rtcmonth = $04
rtcdate = $14
rtchr = $16
rtcmin = $45
rtcsec = $00
Gosub SetTime 'fetch the time
Goto loopy 'goto loopy

loopy:
Gosub gettime ' go fetch the time
Lcdout $fe, 1 'display date on top row on 16x2 lcd
lcdout hex2 rtcmonth, "/", hex2 rtcdate, "/" , hex2 rtcyear
lcdout $fe,$c0 'display time output on bottom line 16x2 lcd
lcdout hex2 rtchr, ":", hex2 rtcmin, ":", hex2 rtcsec
Pause 200 ' pause 0.2
Goto loopy 'return to main loop




SetTime: 'this module sets the time using shiftout
RST = 1 ' bring the DS1302 RST line high and now ready for transfer

Shiftout IO, SCLK, LSBFIRST, [$8e, 0] ' Enable write
RST = 0 ' Reset DS1302 RTC
RST = 1 ' bring reset line high and now ready for transfer
Shiftout IO, SCLK, LSBFIRST, [$be, rtcsec, rtcmin, rtchr, rtcdate, rtcmonth, rtcday, rtcyear, 0] ' Write all 8 RTC registers in burst mode
RST = 0 ' reset DS1302 RTC
Return 'return control to calling program


GetTime: ' Subroutine to read time from RTC
RST = 1 ' reset line high now ready for transfer
Shiftout IO, SCLK, LSBFIRST, [$bf] ' Read all 8 DS1302 RTC registers in burst mode using shiftout/shiftin
Shiftin IO, SCLK, LSBPRE, [rtcsec, rtcmin, rtchr, rtcdate, rtcmonth, rtcday, rtcyear, rtccontrol]
RST = 0 ' Reset RTC
Return 'return control to calling module

End

[Byte_Butcher]

Hmmm. I don't see any code to initialize the RTC. Add something like this to your code, so it runs once before you enter the main loop....
You'll have to look in the data sheet to set your preferred trickle charge rates and such if you are going to use the charger.



'initialize the RTC and set the trickle charge rate
Low SCLK
low rst ' Reset RTC
high rst ' RTC Ready for transfer
Shiftout IO, SCLK, LSBFIRST, [$8e, 0] ' Enable write
low rst
high rst
Shiftout IO, SCLK, LSBFIRST, [$90, %10101011] ' Set charger on and to "2 diodes, 8Kohm"
Low RST ' Reset RTC


steve

[Byte_Butcher]

Ok but I have read in a lot of posts regarding the DS1302 and BCD conversion ..does this still apply ?


If you use a push button to increment the minutes (or hours, etc) you will run into a problem because of the BCD.

This subroutine increments the minutes by 1 every time it's called.
It does the BCD to decimal conversion, increments the minutes, then converts the new number back to BCD before setting the time.


increminute: 'subroutine to do BCD to decimal conversion, increment and convert back to BCD
mathtemp =(rtcmin>>4)*10+(rtcmin & $0F) 'convert BCD minutes into Decimal minutes
mathtemp=mathtemp+1 'increment by 1
If mathtemp>59 then 'If minutes exceeds 59
mathtemp=0 'reset to 0
endif
rtcmin=((mathtemp DIG 1)<<4)+mathtemp DIG 0 'convert Decimal back to BCD
rstcount = 0
gosub settime
return


steve

[Dennis]

@Steve

Thanks for the trickle charger tip :-) now that table makes sense too :-) YAY

I added the code below (originally exactly as you gave it to me) see the updates, I haven't added all the possible options but I will so any line could be un-commented for any selection of the desired charger setup and will post the updates tomorrow sometime.


init:
'initialize the RTC and set the trickle charge rate
Low SCLK
low rst ' Reset RTC
high rst ' RTC Ready for transfer
Shiftout IO, SCLK, LSBFIRST, [$8e, 0] ' Enable write
low rst
high rst
'Shiftout IO, SCLK, LSBFIRST, [$90, %10101011] ' Set charger on and to "2 diodes, 8Kohm"
'Shiftout IO, SCLK, LSBFIRST, [$90, %01011100] ' inititial power state
Shiftout IO, SCLK, LSBFIRST, [$90, %00000000] ' disabled
Low RST ' Reset RTC
return


Sadly the clock is still not working. I still just get a static display.
I have no buttons assigned to the clock as yet,so I didn't add any increment sub-routine..should I ?
I was hoping to just preset the time and it would start ticking away.
If I did add an increment sub-routine , would I need to add one for secs,mins,hours and day month and year ? Or just for mins and hours?

Kind regards
Dennis

Are there any other things I could try ?

Kind regards
Dennis

[Byte_Butcher]

Are there any other things I could try ?


I don't suppose you've got access to a 'scope?
The first thing *I'd* do is probe the oscillator pins on the DS1302 and see if THAT part of the clock is ticking.

steve

[Dennis]

@ Steve

I think I may have found the problem ....
It looks like I am using a 32.768 Mhz Crystal not a 32.768Khz one!
Will get 32.768 Khz crystals tomorrow and confirm :-)

Thanks a million for the info thus far :-)

Kind regards

Dennis

[Byte_Butcher]

Ahhh, yes... the wrong xtal would do it. :)

No amount of fooling with code and registers will help if the hardware is broken.

Last week I spent 2 hours looking over a data sheet to see what registers and settings were wrong when I couldn't get a new circuit to work.
The problem turned out to be 1 unsoldered pin on a 44TQFP part... :o

Let us know how it goes with the right xtal.


steve

[Dennis]

YAY it works :-)

@ Steve .... :-) so easy to miss a pin soldering sometimes or on a breadboard test even forget to put the PIC back into its socket after programming and then watching a blank serial debugger screen :-)
I remember years back in a PC workshop two of the technicians ,on inspection of a 'DEAD PC' that just arrived in, meticulously tested and replaced every component and card (drives,motherboard ,etc) in the PC including the case, eventually out of sheer frustration they called me in to check why it was still dead and the customer had been waiting nearly two weeks for their PC.
I checked the power cable first ... it was plugged into the PSU but it was on a long workbench so I followed the cable to its source... and there was the problem ...the mains switch for the wall plug was OFF :-)

Sometimes even the obvious is not so obvious and often we are in a huge rush, excited to get to the end result as soon as we can.

Thanks Steve and everyone else for all the help so far, I really appreciate it !

Kind regards

Dennis

[Dennis]

@Steve

To add an alarm(s) , would I just store a date and time in flash and then use an IF ..THEN statement as a matching trigger ?

Kind regards

Dennis

[BobK]

Hi Dennis,

You could do that or you could use the DS1337 that has 2 alarms built-in.
The DS1337 uses I2C communications and can be configured in several
different ways. Several years ago, Tony Galea presented an entire program
using the DS1337. Recently, JEllis posted his trials setting up this clock.
It doesn't have a battery charger like the DS1302 but it does have two separate alarm outputs. If you only need one alarm and need a 1hz pulse, the DS1337 will fill your needs. Check out the data sheet. I use alot of them and have a backup battery circuit for them.

HTH,

BobK

[Byte_Butcher]

Or you could just use a 18F46J50 that has a RTCC built in.
*None* of that serial communications junk that way, eh? :)

I still continue to use the DS1302 for a lot of projects because I LIKE the "keep alive battery" and charger...

[Byte_Butcher]

@Steve

To add an alarm(s) , would I just store a date and time in flash and then use an IF ..THEN statement as a matching trigger ?

Kind regards

Dennis

Sure.
Store an alarm hour and and minute (and day if you want), and IF "current minute" >= "alarm minute" AND "current hour" >= "alarm hour" THEN gosub makeahelluvanoise.


steve