32 Mbit SPI flash at 104 MHz — read throughput for code shadowing
The AT45DQ321-MHF-Y is a 32 Mbit DataFlash device from Renesas, organized as 528 bytes per page across 8192 pages. The SPI interface runs at 104 MHz clock frequency, delivering a raw read throughput that shadows firmware or stores data-log frames without stalling the host controller.
Housed in an 8-UDFN Exposed Pad package (5 mm x 6 mm body), the centre paddle conducts heat to the PCB ground plane.
Write and erase timing — firmware update budget
Page write completes in 8 µs typical, and a full page erase takes 4 ms. For a firmware update spanning 100 pages, the erase phase dominates at ~400 ms; the write phase adds under 1 ms. Budget the erase time into the update window so the host watchdog does not expire mid-write. The 528-byte page size aligns with common data-logging sector boundaries — each page holds one complete sensor readout plus a timestamp header without crossing a page boundary.
Active lifecycle and compliance status
ROHS3 compliant, so it meets the current exemption-free RoHS directive without requiring a transition plan.