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AD9542 I2C interface reliability

Category: Hardware
Product Number: AD9542

Hi, we have laid-down an AD9542 in a near-identical circuit to the blue reference board on our own target - the only difference is that we configured it to use the I2C interface with a bit rate of 100kHz.

The problem is that we are still having occasional I2C interface lock-ups, similar to what we saw when we breadboarded our I2C ARM master to the AD9542 on the blue reference board. We assumed this was due to the breadboard low signal integrity (rats nest of wires) and this problem would go away with a proper layout. It hasn't.

Scenario: I want to read out several AD9542 registers every few seconds to check for Reference input status and PLL lock status. Unfortunately, after a relatively short time (seconds, minutes or hours) the I2C master times-out, requiring a reset of the AD9542.

Fundamental question: Is the I2C interface suitable for polling status in this way or should we use the SPI interface? Is there anything else that I have missed?