Flash Access; Reading Flash - Analog Devices ADuCM356 Reference Manual

Reference Manual
FLASH CONTROLLER
When writing to these locations, the user must always write
0xFFFFFFFF to the reserved locations. If the user intends to write
to either location at run time, ensure that these reserved locations
remain all 1s (0xFFFFFFFF). If data is stored to these reserved
locations prior to run-time modification of the neighboring metadata
spurious, ECC errors are likely generated when this metadata is
read.
The top reserved words of metadata are utilized by the flash con-
troller to enable protection and integrity features. For more details
about these features, see the
Bus errors are generated if user code reads from a protected or an
out of bounds address. Writes or erasures of protected addresses
result in appropriate error flags set in the status register. The
address setup for writes and erasures is automatically constrained
to the flash address range.

READING FLASH

The flash controller provides two interfaces for reading nonvolatile
storage: ICode and DCode. The ICode and DCode interfaces are
analog.com
Figure 52. ADuCM356 Flash Memory Structure, Top of Page 128, Address 0x3F800 to 0x3FFFF
Protection and Integrity section.
Figure 53. Flash Memory Read and Write Data Paths

FLASH ACCESS

Flash memory can be read, written, and erased by user code.
Read access is provided through the cache controller using two
AHB ports (as shown in Figure
DCode for data. Write access is provided through keyhole writes
using APB control of memory mapped registers. The keyhole write
implementation includes support for both DMA-based and manual
user initiated writes.
accessed through the cache controller module through the AHB.
The flash controller includes a prefetch buffer for ICode, by which
it is possible to return data on both ICode and DCode interfaces in
the same cycle.
Flash memory is available to read only after an automatic initializa-
tion process. Attempts to read during the flash controller initializa-
tion lead to a stall. Reads also stall if the flash controller is already
busy performing another command (such as writing the flash),
unless the prefetch buffer satisfies those reads.
ADuCM356
53): ICode for instructions and
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