Using DS2482-100 to communicate with DS28E05

Question

Actual setup

Today, I use a CY8CKIT-043 connected via I2C to a AK-DS2482S-100 to communicate with a DS24B33 eeprom chip.

In normal operation, only one onewire chip is connected to the DS2482S board.

All is working well. The main board is powered by usb. I communicate with it thanks to the kitprog, and I can read and program the eeprom easily.

The DS2482 is powered by 3.3 V.

Problem

The first chip I use is now no longer available, so I tried to find a new one compatible with the actual setup. But I don't have the competency to be completely autonomous on that subject.

New candidate : DS28E05.

I didn't expect to be able to read the memory on the first test. But changing the old chip to the new one, I can't even read the OW RomID, which should be less or more standard across different OW chips.

Questions:

• Was I too naïve thinking I could just swap a chip by another?
• How can I compare the chips?
• Is a circuit able to read both kinds of OW chips (not at the same time) feasible?

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Hypothesis

I think -but I'm not sure- that the main difference between the two chips is the speed. The new one only supports highspeed communication "Overdrive". I'll dig in that direction.

Answer 1

As guessed (see hypothesis) the two chips doesn't start in the same speed mode.

The old start in low mode (and can be set to high speed)

The new one only work in high-speed mode.

Solution:

I have to play on the DS2482 configuration register, setting the 1WS bit (One wire speed) to one.

To be compatible with my actual setup, I'll constantly change the DS2482 speed configuration: 1 second in high speed, 1 second in low speed until a rom is found.