Knowledge Base

Shadow memory allows any parts of SPLat RAM to be saved and recalled.  So it allows more storage than Permament Memory but doesn’t have any status information.  So if you need to know if the data you’re recalling is valid, you’ll have to implement your own checksum or flag mechanism.

Writing to shadow memory typically only takes a few milliseconds but it can sometimes be quite slow, taking up to 100ms.  During this time your control application will be stalled, so ensure your machine is in a safe state before performing a ShadowWrite or ShadowClear.

Shadow memory endurance on the HMI430/700 is greater than 320,000 writes.  There is no limit to the number of reads.