I’m using an Arduino (italy) Mega with the Seeed W5500 Ethernet Shield for reading analog inputs from potentiometers.
The Card and shield are connecting OK -
Here’s the problem -
On Analog pins 4 and 5 (on the shield) im seeing increased values as compared to the Mega (without shield) or, with my older Arduino 5500 Ethernet 2 card -
All Unused analog pins have been set to LOW (6,7,14,15)
Eg: the approx mid point of the pot on A4 shows a raw value of about 620 (+/- 1) when using the Seeed shield, and shows about 500 (+/- 1 ) when using the Arduino Ethernet2, or without the seeed shield
As i can see that the analog pins are just “connect thru” on the shield, i dont know why im seeing an increase in value/voltage…
Im using the Ethernet2 library…
If you use the non-I2C analog port, the reading is the same with/without w5500 shield.
the w5500 is connected the a4/a5 with scl and sda.
for mega, the sda/scl are 20/21.
So i think the w5500 shorts the a4/a5 with scl and sda, then the pull up resistor impacts the readings. thanks.
oard I2C / TWI pins
Uno, Ethernet A4 (SDA), A5 (SCL)
Mega2560 20 (SDA), 21 (SCL)
Leonardo 2 (SDA), 3 (SCL)
Due 20 (SDA), 21 (SCL), SDA1, SCL1
ill check it out
are you saying i should avoid using A5/A5 on the 5500 shield with the mega?
Please use the a0~a3, thanks.