I have four questions. First, can I read data from EPC memory and user memory at the same time? Second, can I write data to EPC memory and user memory at the same time? Third, if I wanted to change only the data in the user memory and not in the EPC memory, would that be possible? And fourth, is this an efficient and frequently used method?
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I spoke with Andrew Malo and James Heurich, engineers at RFID Inc., who told tell me the following:
"When it comes to reading EPC and user memory concurrently, normally the EPC section of the tag is reported right after anti-collision resolution and is sent without the need to select the specific tag. Reading user memory and writing any part of the tag at the same time would require the extra step of selecting the tag. This is a little slower than just reading the EPC. The only part of memory that can be read at the same time as the EPC is the TID and only some tags that have that feature. Writing data requires you to specify block, word address and word count. To write to user memory, you would have to specify those parameters. So currently you can't write EPC and user blocks at the same time. Companies could create firmware to do it and thereby enable two write operations in a single write command."
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