When operating in bidirectional mode, what event initiates SDIO going tristate, and what's the delay from this event to SDIO tristate?
Thanks Matt. Could you just check one more thing for me please?
In point 1 of your answer you state that SDO goes tristate when CSB is high. This appears to conflict with the following statement in the datasheet (Rev C):
"SDO (serial data out) is used only in the unidirectional I/O mode as a separate output pin for reading back data. SDO is always active; therefore, the unidirectional I/O mode should not be used in a multislave environment."
Could you confirm that your statement overrides the datasheet, or am I missing something? I would prefer to use the SDO pin rather than bidirectional SDIO, but assumed from the datasheet that this was not possible with my multislave bus.
The SDO is always driven in unidirectional IO mode (so it does NOT tristate when CSB is high) – so the datasheet is correct.
The AD9524 was the first dual loop device we taped out and we changed it for the AD9523 and AD9523-1, these 2 devices SDO will go tristate when CSB is high.
All new AD9524 parts ordered (date code 1243 and higher) will have SDO and SDIO tristate when CSB is high. Rev D of the datasheet reflects this change.
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