MAX7219 and Basic Stamp

Moskog

I am currently working on a project on pre-heating water before the water reach the water tank in the basement. I am using energy from the ground heat pump in the basement that usually heats the floors in my house, using some 40·C hot water.
After heating the floors there are still some energy in the water that I can use for pre-warming the hotwater.

The hardware is up and running and works great but I still have no control over the system. I need to know the temperatures on different places to tell the microcontroller when to start or stop the pre-heating circulation pump.· I am planning to use four LM35 temperature sensors and also display all different temperature readings on four two-digits LED-displays. Like·showing the temperature on the floor-heating water, the temp on the pre-heating tank and also the temp on the hot-water tank.

First I planned to use two MAX7219 LED drivers, each driving two double displays. (Four digits)
To drive those two double displays it seems that·I need at least one 13-bit variable, this can easily be done with a Word.

Now I wonder if it is possible for the BS2 to tell the MAX7219 to drive all four double displays I need, (all eight digits)
What I need is also to display 4 temperature readings, each 2 digits with one single MAX.
(All four double displays can be seen like one 8-digit common cathode display by the MAX)

Example: My temperatures:· 40, 35, 38, 60 [noparse][[/noparse]C]
MAX7219 will then display: 40353860.··· <--- a 26-bit value

So, is this possible for the BS2 and if so, can anyone help me to understand how?

Or do I have to use two display drivers instead?

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An additional question when using two MAX7219:

Can I share Data and Clock-line on the 7219, as I understand the Load is a bit different compared to the traditionally Chip-Select line on other IC's.







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KjellO

eod_punk

That can be done easily as the MAX7219 can display 8 digits.··The BS2 basically tells the MAX7219 what number is in each digit using BCD (Binary Coded Decimal).· Check out this project·for a solder pot controller by Chris·Savage, a Parallax employee,·that is very similar to what you are trying to do.

http://forums.parallax.com/showthread.php?p=637023

Here's a different project of his where he did share the data and clock lines with a DS1302, DS1620, MAX7219, and three 74HC595's to make a binary/digital clock.
http://www.savagecircuits.com/forums/showthread.php?164-Binary-Digital-Clock
·

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There is no problem that can't be solved with a suitable amount of explosives!

EOD Memorial

Moskog

Thanks, eod_punk, Chris' codes are always good sources when learning smart programming technics.

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KjellO

Chris Savage

I know this is an older thread, but thanks guys!