The R5F100BF is the 96 KB member of the 32-pin row: a 5 by 5 mm HWQFN with
8 KB of RAM, the 8 KB data flash that begins at this capacity, eight converter
channels and twenty-eight I/O. It is the first part of the row on the far
side of the 64 KB boundary, and the boundary matters twice: the data array
doubles, and the firmware that justifies this capacity almost always uses the
boot swap machinery that turns the first eight kilobytes into a two-cluster
update zone.

Crossing the data-flash boundary

Every member up to 64 KB of code flash carries a 4 KB data flash; from 96 KB
upward the array is 8 KB. The larger array is what makes long-lived logging
practical, and appliance and metering firmware at this capacity leans on it:
fault records, calibration generations, usage counters. For a recovery job
the array is proportionally the most valuable kilobytes on the chip, because
it holds the unit’s operating history in a structure the code alone cannot
supply. It is read with the data-flash command set and captured with its own
protection configuration noted.

Ninety-six blocks and eight KB to work in

The code array divides into ninety-six blocks, the first four being the boot
cluster with the swap target at 02000H. The 8 KB of volatile memory runs the
flash library with room to spare, and the self-RAM reservation in a recovered
linker map marks an image built for updates. In-circuit readout on this
member is comfortable: the sequencer’s idle time belongs entirely to the read
path, and the loader fits in volatile memory while the application keeps its
own state.

Protection at this capacity

The option bytes at 000C0H to 000C3H, the ten-byte debug ID at 000C4H, the
ten-byte serial ID at 000CEH and the shipped block protections are
family-standard. What changes at 96 KB is emphasis: the boot-area
reprogramming protection is load-bearing because the swap feature is in
active use, and the shield window, where firmware uses it, confines updates
to blocks the author chose. Both settings are captured as part of the image
because a repaired board needs them restored exactly.

QFN access and the two identifiers

The 0.5 mm wings carry TOOL0, the UART pair and the supplies, and layouts
with test pads make the serial path the natural first connection. The serial
identifier usually gates it; the debug identifier varies; and the erase bit
in 000C3H decides how unforgiving a wrong emulator connection would be. The
passive read of block 0 resolves all three before anything active happens,
which is the order of operations on every member and doubly so on a part
holding 96 KB of firmware history.

Row context

The 32-pin siblings are in R5F100BA locked flash through R5F100BE embedded memory and the
128 KB R5F100BG flash data. The 96 KB die in leaded packages is the 30-pin
R5F100AF memory readout and the 40-pin R5F100EF flash memory. For the same capacity in a
family with no separate data array and a single protection word, see
MC9S08DZ128MLF encrypted microprocessor. The reproduction flow that reconstructs both arrays is the
IC clone service page, and the general family index is microcontroller unlock.

What ninety-six blocks buy

The program array at this capacity is ninety-six erase blocks, and the
update machinery typically occupies the bottom eight, leaving
eighty-eight for an application that now has room for protocol stacks,
logger modules and multi-language string tables side by side. On the
bench the size changes the rhythm of a capture: the full array still
streams out in seconds, but verification becomes worth doing per block,
because a 96 KB capture with one bad kilobyte is a plausible image in a
hex editor and a broken controller in the field. The doubled data store,
at 8 KB, is read in the same session with its own command set.

Field-updated boards of this class nearly always carry two generations in
the boot copies, and the older one is worth reading even when the job is
only a repair. Patched routines, recalled constants and abandoned debug
hooks all survive in the inactive copy, and a diff between the halves is
the fastest available explanation of what the manufacturer changed and
when.