In SX Microcontrollers, SX/B Compiler and SX-Key Tool, gtslabs wrote:

I have not seen much here in the SX forum on the DS18B20 temperature sensor.  A few months ago I had made a simple project measuring 8 different sensors using a Picaxe. Now I need to measure 26 different sensors and though to use my SX48 protoboard.

 

I am looking at 2 different approaches. 

1) use a different input pin for each sensor and thus knowing the physical location of each based on where it plugs into the board. Then read each sensor.  Can I loop thru different ports RB0..7, RC0..7, RD0..7,RE0..1 in one continous for loop?  Or do I need to make each port group a separate loop.  

 

2) use the 1-wire bus.

I read thru the DS18B20 datasheet and it does not look like I can get a temperature reading and Serial Numer from one memory scratchpad location.  I would have to first loop thru all the serial number saving them to memory then loop back thru these 64 bit serial numbers for MATCH ROM to get the temperature of each device. I can see that I would be limited by my memory size with 26+ 64bit ID's to store.

 

So with the first approach I am limited to the number of ports on the board where the second approach I am limited by memory.  Any ideas on how to best go about this?

 

Thanks

Steve

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