How to connect 4 x 24LC256 to DUE

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Please see attachment. Im not sure if this is correct.

Thanks

24LC256 parallel.pdf (6.96 KB)

Your pdf shows eight devices, not four.

You miss pull-up resistors on the I2C bus and decoupling capacitors (one for each IC).
Otherwise it looks OK.

wvmarle:
You miss pull-up resistors on the I2C bus and decoupling capacitors (one for each IC).
Otherwise it looks OK.

I placed 1x 10K between 5V - SCL and 0V - SDA

Where and what size are the decoupling caps suppose to be?

Thanks

fnb111:
I placed 1x 10K between 5V - SCL and 0V - SDA

You should have a pullup resistor of about 4.7K for both SCL and SDA. You should not use a pulldown resistor.

fnb111:
Where and what size are the decoupling caps suppose to be?

100nF, one for each 24LC256. They should be connected to pin 7 and pin 8 (VCC and GND) and be as close to the pins as possible.

Both SCL and SDA need pull up resistors, not pull down.

With 8 devices on the bus they may need to be a bit stronger. That's gotta be quite some pin capacitance to overcome.

For the decoupling caps: unless the datasheet says something different the usual will do. 100 nF ceramic, one per IC, placed as close as possible to the Vcc pin.

SDA and SCL lines of the DUE have already their pull-ups (1K Ohms to 3.3V !).

ard_newbie:
SDA and SCL lines of the DUE have already their pull-ups (1K Ohms to 3.3V !).

Thanks every body.

ard_newbie:
SDA and SCL lines of the DUE have already their pull-ups (1K Ohms to 3.3V !).

Yikes, I didn’t realise that!

OP, I hope you didn’t use a pullup to 5V on your 3.3V Due.

BJHenry:
Yikes, I didn't realise that!

OP, I hope you didn't use a pullup to 5V on your 3.3V Due.

I fitted an EEPROM to a board and the power is supplied from another source. Not from the DUE board. Is this acceptable?

Thanks

fnb111:
I fitted an EEPROM to a board and the power is supplied from another source. Not from the DUE board. Is this acceptable?

Thanks

If the pullup was connected to 5V, then it will have put +5V onto the pin of your Due. That's bad news.

fnb111:
I fitted an EEPROM to a board and the power is supplied from another source. Not from the DUE board. Is this acceptable?

Depends on the voltages involved and the actual circuit.

A 10k pullup to 5v is not likely to damage a 3.3v pin. The clamping diodes will take care of that.