Picaxe 40x1 > ds1307, All values hashed

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Lachlanmiller

Member
Hi guys i have a picaxe 40x1, and just bought a ds1307 chip from dontronics today, i put it in my breadboard, inserted the crystal between pins 1 and 2, put in a cr2032 battery on pin 3, gnd on pin 4, vcc on pin 5, and led with a resistor to vcc on pin6, slc on pic 7, sda on pin 8.

i tried the ds1307 sample program (adding the /16's) and was getting values like 152/152/178 etc

then tried the following simple program :

main:
i2cslave %11010000, i2cslow, i2cbyte
readi2c 0, (b0,b1,b2)
sertxd(#b2,":",#b1,":",#b0,13,10)
pause 1000
goto main

but all i get is :

255:255:255


i am using the 28x/40x proto board. with all the jumpers in the default positions.

Thanks
Lachlan
 
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Lachlanmiller

Member
edit :

It appears now its running through the program ( i put a sertxd("main loop") inside main: and i get lots of main loops, but nothing from the i2c not even 255's
 
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Lachlanmiller

Member
ok, now that the data lines are tied high with a 5k1 resistor, it seems to be working flawlessly, although after i set the time with the datalogger>ds1307 time set wizard, its displaying 17:03 when its 5:44 ?
 
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Lachlanmiller

Member
this is the code i am using to display the time


the code at the bottom is used to set the time at 6:00 pm or 18:00 the clock is displaying 17:19

i must have hashed something, also i dont quite get if im using the numbers correctly when setting the time, it seems to be that i enter the decimal number with a $ infront of it and it becomes bcd ? well thats what the ds1307 example illustrates.


Code: 
symbol seconds = b0
symbol mins = b1
symbol hour = b2
symbol day = b3
symbol date = b4
symbol month = b5
symbol year = b6
symbol control = b7
symbol temp = b8

' set DS1307 slave address
	i2cslave %11010000, i2cslow, i2cbyte


' uncomment this line to update the clock time
' goto start_clock 


' read time and date and display on serial LCD module

main:
	readi2c 0,(seconds,mins,hour,day,date,month,year)
	
'	debug 
		
sertxd(13,10)

	let temp = date & %0011000 / 16
	sertxd(#temp)
	let temp = date & %00001111
	sertxd(#temp,"/")

	let temp = month & %0001000 / 16
	sertxd(#temp)
	let temp = month & %00001111
	sertxd(#temp,"/")

	let temp = year & %11110000 / 16
	sertxd(#temp)
	let temp = year & %00001111
	sertxd(#temp," ")

	let temp = hour & %00110000 / 16
	sertxd(#temp)
	let temp = hour & %00001111
	sertxd(#temp,":")

	let temp = mins & %0111000 / 16
	sertxd(#temp)
	let temp = mins & %00001111
	sertxd(#temp,":")

	let temp = seconds & %01110000 / 16
	sertxd(#temp)
	let temp = seconds & %00001111
	sertxd(#temp)

	pause 5000
	goto main



'write time and date e.g. to 11:59:00 on Thurs 25/12/03
start_clock:
	let seconds = $00	' 00 Note all BCD format
	let mins    = $52	' 59 Note all BCD format
	let hour    = $17	' 11 Note all BCD format
	let day     = $03	' 03 Note all BCD format
	let date    = $18	' 25 Note all BCD format
	let month   = $01	' 12 Note all BCD format
	let year    = $10	' 03 Note all BCD format
 	let control = %00010000 ' Enable output at 1Hz

	writei2c 0,(seconds,mins,hour,day,date,month,year,control)

	end
 
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Lachlanmiller

Member
and then while im looking at the input buffer and tv simultaneously


18/01/10 17:19:04
18/01/10 17:19:08
18/01/10 17:19:13
18/01/10 17:19:18
18/01/10 17:19:23
18/01/10 17:19:28
18/01/10 17:19:33
18/01/10 17:19:38
18/01/10 17:19:43
18/01/10 17:19:48
18/01/10 17:19:52
18/01/10 17:19:57
18/01/10 18:00:02
18/01/10 18:00:07
18/01/10 18:00:12
18/01/10 18:00:17
18/01/10 18:00:22
18/01/10 18:00:27
18/01/10 18:00:32
18/01/10 18:00:36

it just jumped 40 minutes and appears to be working ?
 
P

Pfrogs

Member
You managed to jump forward in time..that should be something! :D

Sorry, I've never worked with ds1307 before, but certainly soon someone will help you explain this phenomenon. Just couldn't help it commenting your Back to the future clock ;)
 
hippy

hippy

Ex-Staff (retired)
It hasn't jumped 40 minutes. If the time were not "17:19:57" but "17:59:57" then the following "18:00:02" would be right, and looking at the tens decoding for minutes ...

let temp = mins & %0111000 / 16

You've got a missing zero, it should be -

let temp = mins & %01110000 / 16

You have similar bugs elsewhere.

You enable the LED to flash at 1Hz in your program :)

Previously removed ( sorry - had misread where the OP indicates LED is working ) : I believe the SQW LED has to be enabled and SQW can only sink current so the LED+R has to connect between +V and pin.
 
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MartinM57

Moderator
Lachlanmiller said:
also should the led connect to the sqw pin, flash once a second? it currently is, i assumed that it was meant to be 1khz though.
Click to expand...
Yes, but as Hippy says, from +V via a resistor to the SQW pin.

Have a look at the data sheet for the CONTROL register settings. %00010000 enables SQW output at 1Hz - so all is well. Unfortunately, you can't get 1Khz out of SQW...
 
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Lachlanmiller

Member
thanks guys.

i didnt write that code at all, it is purely the ds1307 sample code, but i added the /16

shouldnt that get updated with the changes?
 
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MartinM57

Moderator
Lachlanmiller said:
it is purely the ds1307 sample code
Click to expand...
From where?

EDIT: I see no official (aka Rev-Ed) code samples that are incorrect - but a lot of incorrect code being posted around the Internet. Remember, 'not all you read on the Internet is correct'...
 
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Lachlanmiller

Member
rather than echo'ing the value out of the serial port, the high nibble first then the second.

let temp = hour & %00110000
serout 7,N2400,(#temp)
let temp = hour & %00001111
serout 7,N2400,(#temp,":")

how can i convert the bcd value hour, to decimal and store it in hour again?
 
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MartinM57

Moderator
MartinM57 said:
I see no official (aka Rev-Ed) code samples that are incorrect
Click to expand...
...that's because I've never looked in that folder (didn't know it was there!).

There does appear to be an error with a missing 0 in some of the masks - but I'm confused whether your /16 is in your code now or not ... it shouldn't be there if you have the masks correct? EDIT - of course it should be there. Engage brain before typing MartinM57 ;)
 
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hippy

hippy

Ex-Staff (retired)
Lachlanmiller said:
i didnt write that code at all, it is purely the ds1307 sample code, but i added the /16
Click to expand...
The sample code was incorrect, and both the "/16" and incorrect bit masks have been corrected but there hasn't been a subsequent BAS805 Programming Editor release since which explains its lack of propagation. The sample code will be fixed in the next release.
 
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Lachlanmiller

Member
fantastic, thanks for all your help hippy.

it looks as if everything is working perfectly for now, i will have to figure out how to convert the bcd to decimal without just sending the first nibble out and then the second, maybe i store the first in temp 1 the second in temp 2 and "&" them together ?
 
hippy

hippy

Ex-Staff (retired)
Or -

ReadI2c ..., ( ... hour ... )
temp = hour & %00110000 / 16 * 10
temp = hour & %00001111 + temp
SerTxd( # temp )

"temp = BcdToBin hour" will achieve the same.
 
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Lachlanmiller

Member
thanks heaps. I am currently using the bcdtobin functions, but i wanted to use some other chips that dont support that function.

Thanks again.
Lachlan
 
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