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Topic: Arduino DUE, Mega 2560 or UNO with MAX31865 for reading PT100 with screen (Read 8958 times) previous topic - next topic

alperenakkus

Hi Moderator,
I am beginner to arduino and i want to make a temperature controller with PID. Because i want to learn arduino with this project. But i don't know how to connect arduino and Max31865. For exmaple:
                         
                      MEGA 2560 Pins | Arduino DUE pins | Arduino UNO Pins
DRDY---->                                |                              |
SDI------>                                 |                              |
SCLK---->                                  |                              |
CS------>                                   |                              |
SDO---->                                   |                              |

Please help me :( how connect?

CrossRoads

Have you looked at the MAX31865 data sheet?
It is a 3.3V part. You will need a part like 74HC4050 to translate the 5V IO from the Uno to 3.3V to to MAX31865 on the the SCK, MOSI, and CS pins. MISO and DRDY from the MAX31865 back to the Uno will be fine.

Other than that:
SCK goes to SCLK
MOSI goes to SDI
MISO goes to SDO
SS goes to CS
DRDY can go to any pin.

If you browse for MAX31865, I posted code from MAXIM for interfacing to the MAX31865.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

alperenakkus

Thanks for your reply CrossRoads ,
But i didn't understand. 74HC4050 have this pins: Vcc 1Y, 1A, ...6Y, 6A, GND and Nc.

MOSI is pin 11
MISO is pin 12
SCK is pin 13
SS is pin 10 (on UNO) But SCK (pin13) how connect 74HC4050 and then go to SCLK. Example

SCK (pin13) goes Vcc, and then from Nc to SCLK. Is it right?


CrossRoads

Power the 74HC4050 from 3.3V and Gnd.
Connect an Uno output to a '4050  input - then the 4050 output goes to a MAX31865 input, and will be at 3.3V levels.
Example: Arduino SCK to '4050 Pin3, '4050 Pin2 goes SCLK on MAX31856.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

alperenakkus


alperenakkus

Sorry for using leonardo picture. Plesae assume it to be Uno.

CrossRoads

No. DRDY and SDO are outputs back to the Arduino, so you would need to switch the A & Y pins, or just bring those 2 back with no buffering.
That is more than just a MAX31865.
Read the datasheet on the little board. It might have buffering on it already.
I would be very suspect of bringing Vin from the Arduino as well; more likely, just 5V is needed. Read the little board's datasheet.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

alperenakkus

Sorry CrossRoads, i am very new arduino and i read datasheet but i didn't understand anythig, so please help me again, this picture help very people. This schematic picture is right?


CrossRoads

I can't open tinypic . com.
Click Modify, Additional Options, browse to your locally stored file, and Attach it.
Your connection diagram looks better.
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

alperenakkus

I already attached it, locally and tiny pic. Couldn't you see?

CrossRoads

Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

alperenakkus


CrossRoads

Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.


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