ZENTRUM MIKROELEKTRONIK DRESDEN AG
“ASI for you” IC
Datasheet
There is one exception to this principle. If the IC is operated in Extended Address Mode, Bit3 of the re-
turned slave response is taken from the ID_Code_Extension1 register in the User Area. This is because
Bit 3 functions as A/B Slave selector bit in this case and must remain user configurable.
To ensure consistency of ID_Code_Extension1 stored in the data image of Master as well as in the
E²PROM of the slave, the ASI4U will not process a Write_ID_Code1 request if the data sent does not
match the data that is stored in protected part of the ID_Code_Extension1 register. It will neither access
the E²PROM nor send a slave response in this case.
Note: As defined in the AS-i Complete Specification a modification of the A/B Slave selector bit must be
performed bit selective. That means the AS-i Master must read the ID_Code_Extension1 first, modify
Bit3 and send the new 4 bit word that consists of the modified Bit3 and the unmodified Bits 2 … 0 back
to the slave.
•
If the ID_Code1_Protect flag is not set (‘0’), ID_Code_Extension1 is completely user configurable. The
data to construct the slave response to a Read_ID_Code_1 request is completely taken from the
ID_Code_Extension1 register in the user area.
In this configuration a Write_ID_Code1 request will always be answered and initiate an E²PROM write
access procedure.
Copyright © 2006, ZMD AG, Rev.1.4
All rights reserved. The material contained herein may not be reproduced, adapted, merged, translated, stored, or used without the prior written consent of the copyright owner. The
Information furnished in this publication is preliminary and subject to changes without notice.
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