R5F100GH is the 192 KB member of the 48-pin row: three segments of program
space, 16 KB of RAM, the 8 KB data array, ten converter inputs and
forty-four I/O in the 7 by 7 mm LFQFP on a 0.5 mm pitch. It is the capacity
where an industrial image stops being a single program and becomes a program
plus a library of versioned modules, and where the update machinery, the
banked addressing and the doubled data array are all load-bearing at once.

One hundred ninety-two blocks in three windows

The erase grid is one hundred ninety-two blocks of one kilobyte. The lowest
four form the boot region and the four from 02000H hold its mirror;
everything above belongs to the application, which spans three 64 KB windows
of the core’s one-megabyte space. Code and constant tables are banked
through the segment register, and the vectors plus the security
configuration stay pinned in the default window at the bottom of the array.
A capture therefore has to be verified block by block and reassembled
bank-aware: an image rebuilt without its segment assignments disassembles
convincingly and boots nowhere.

Sixteen kilobytes of working memory

The volatile memory carries the flash library, the update protocol, the
communication stack and the application’s working set together, with the
library’s reserved region marked at the top of RAM in every image built by
the standard tooling. Both boot copies are populated on nearly every board
of this capacity, because field updates are the reason a design chose it,
and the flag byte in the first block records the live generation. The
inactive copy preserves the firmware the product was born with, and
comparing the two halves dates and explains every update the board ever
received.

The 8 KB data array

The separate store holds fault histories, calibration revisions and usage
counters under wear levelling, in its own blocks with independent
protection flags and its own command set. On drives, chargers and gateway
controllers built around this member, that log is frequently the only
surviving record of how the unit was run and serviced, and a rebuilt
controller without it starts its life with no memory of its own board.
Capturing the array in the same session as the code, with its flags
recorded, is the standard here rather than an extra.

Security posture

The first kilobyte carries everything that decides how closed the chip is:
four option bytes for watchdog, detector and oscillator policy, the fourth
doubling as the debug gate with its wipe-on-failure choice, and the two
ten-byte secrets that gate the emulator and the TOOL0 programmer
independently. Half-configured boards, one secret written and its twin
forgotten, are as frequent here as anywhere in the family and usually define
the working route into the image. The block is read passively, before any
tool attaches, in every job on this member.

On the bench

The leaded body cooperates: 0.5 mm leads take a pitched fixture, and the
part lifts and re-balls cleanly when the layout hides its wires. The
streaming capture is a single-session walk of the full array and both data
regions with per-block verification, and only a damaged die escalates to the
physical layer. Imaging practice is on the firmware extraction service page and package-level
work on IC decapsulation service.

Context

Below in the row is R5F100GG memory dump and the row opens at R5F100GA memory readout;
above, the row continues to the half-megabyte R5F100GL firmware decryption. The same 192 KB
capacity appears in the 40-pin R5F100EH firmware decryption and the 44-pin
R5F100FH flash data, the closest references for cross-package planning. The
boot-swap mechanism that the update story rests on is treated in
R5F100FE boot cluster recovery.

Reading a three-window image in practice

The three 64 KB windows divide labour predictably at this capacity: the
lowest holds the boot and update machinery, the middle carries the
application proper, and the upper holds libraries, tables and the
versioned modules that field maintenance revises. The division is
visible in a capture and in the wear pattern of the blocks, and it
gives a repair its map, because changes concentrate in the upper
windows while the lower ones stay pinned. A session that reads all
three windows with per-block checksums, both boot copies and the 8 KB
data store finishes with a self-consistent picture of the unit that no
partial capture can offer.