Stacking Arduino Uno with Ethernet shield W5100 and I2C-shield PR14-3


#1

I have an I2C-shield PR14-3 connected to a 4-channel 4-20mA Current Receiver PR33-15 with I2C-cable. As long as the I2C-shield is connected directly on top of an Arduino Uno, the data-transmission from the receiver to Arduino works fine.
As soon as I try to stack several shields, for instance the I2C-shield PR14-3 together with a W5100 Ethernet-shield, only the shield directly on top of the Arduino is detected and not the upper one. To have all pins connected, it looks reasonable to have the W5100 sandwiched between the Arduino and the I2C-shield. In this case only the Ethernet-shield is detected and not the I2C-shield with the receiver. I suppose there is a conflict of common pins.
Is there a solution, stacking these shields together or do I have to use another Ethernet-shield ? The use of an Ethernet-shield is necessary, as any Wifi-solution is not advisable.


#2

the arduino i2c shield only usages SDA, SCL, 5V and Gnd pins.
check the Ethernet shield connections. If its W5100 based, it should be using SPI lines only.


#3

The Ethernet shield W5100 has no SDA- and SCL-pins. With an I2C on top of the W5100, the SDA and SCL pins have to be bridged to the Arduino. Then both shields are operational.
Vice versa does not work: although all pins of the W5100 are connected through the I2C to the Arduino, the W5100 cannot establish an Ethernet connection. I tried with several W5100. Quite strange.


#4

can you share a picture of your setup?

Thanks


#5

I don’t like this configuration with I2C-board on top. To put a bridge for SDA + SCL, the 2 pins at the I2C-board have to be twisted. But this configuration works.
The other configuration with W5100 on top and I2C-board sandwiched is not working properly, a Ethernet connection does not connect, although all W5100 pins are directed through I2C-board.