need a bit of help with this snippet of code

mcnscott2 · Joined: 25 Mar 2007 Posts: 19

I'm still working on this time and temp clock, I'm trying to make it say the time and temp on the quarter hours now, so I've modified the code some. The problem I'm having is the program works when the first designated time is reached, x:00, x:15, x:30, x:45, however, it won't work again. The clock and temperature keep running fine, however my say_time, say_temp functions won't work. Any clues?

jecottrell · Joined: 16 Jan 2005 Posts: 559 Location: Tucson, AZ

Sure you don't mean:

mcnscott2 · Joined: 25 Mar 2007 Posts: 19

I'll give that a shot anything is better than pulling my hair out Shocked

jecottrell · Joined: 16 Jan 2005 Posts: 559 Location: Tucson, AZ

If you look at the order of operations in the compiler manual the ! operator is evaluated before the &&. Also, what you were trying to express was:

mcnscott2 · Joined: 25 Mar 2007 Posts: 19

I gave that a shot, and tried to change the false true statements in a couple places but nothing worked, still says time and temp on the quarter hour then never again, I changed my times though 30, 31, 32 instead of 15, 30, 45. Here is the original code by Bruce Reynolds, I've confirmed this works. Every hour on the hour it says the time and temp.

It's got me baffled too John, thanks for the help Smile

I can't think of another way to put it in the code my psuedocode is:

1. if the time is x:00 or X:15 or X:30 or x:45
2. say time and temp
3. if the time and temp announcement has gone off
4. don't say it again until the next quarter hour.
(I messed with the || in place of the && for the second statment of the code and it kept saying the time and temp every 5 seconds instead of once.

jecottrell · Joined: 16 Jan 2005 Posts: 559 Location: Tucson, AZ

Try this. I think you have an order of operations problem...

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

You may have problems with operator precedence, but your main
problem is that you've stuck a "0x" in front of all your time values.
This turns 15 minutes into 0x15 minutes, which is actually 21 minutes.
That's why it only works with 0x00. Even as a hex value, 0 is still 0.

mcnscott2 · Joined: 25 Mar 2007 Posts: 19

I know the hex numbering looks strange but it's not hex really, I have to put in the decimall minutes I want for the function to work, instead of 1E it has to be 30, 45 instead of 2D etc. Here is the code for the function that actually reads the time.

PCM programmer · Joined: 06 Sep 2003 Posts: 21708

You must be leaving the minutes in the BCD format used by the DS1307.

I made a test program and put in the same fix for operator precedence
that jecottrell suggested. It seems to work. It displays the time every
15 minutes. I didn't test it with all time values. You might test it further.

mcnscott2 · Joined: 25 Mar 2007 Posts: 19

I'll give it a try thanks !

well your code worked for me, but it had me perplexed because I was sure, I had tried that operator arrangement many times, I finally figured out the problem.

I was trying to save time so instead of waiting 15 minutes for the message I had my time parameters set up at x:30, x:31,:x32, x:33 sooo.... The program never got a chance to play the next message because it saw that if the time was equal to x:31 it must have already played the message so it never played it, same for when the time got to x:32, then x:33. I can finally go to sleep! thanks everyone!

Ttelmah · Guest

Well done.
This little 'catch', is very common. It is why (for instance), you will see people who are aware of this, using an interrupt 'counter', and coding like:

(in the interrupt)

if (counter) --counter;

(in the main)

if (!counter) //operations here to be done when counter==0

Rather than checking for a counter getting 'to' a particular value. The risk of missing a particular 'count', gets even higher, when there are multiple asynchronous interrupts enabled, and this can be a pig to discover...

Best Wishes