One hundred and twenty-eight kilobytes of flash in a 64-pin RX24T is a deliberate compromise: enough code for a sensorless field-orientated control loop, not enough for a protocol stack on top of it. R5F524T8ADFM is that part, and the designs built around it are usually single-purpose – a fan driver, a small pump, a compressor controller with one job and a fixed set of parameters.
The Address Moves With The Capacity
On RX24T the code window starts at the top of the 4 GB space minus the array size. For a 128 KB device that is FFFE0000h, not the FFFC0000h that the 256 KB parts use. Reading with the wrong base produces an image where the reset vector looks plausible and every absolute address is 128 KB off – a failure that shows up only when the code executes, never at merge time.
What Fits In 128 KB
In practice: the control loop, the state machine around it, the fault handlers, a parameter block and a small bootloader. What usually does not fit is a full CANopen or Modbus stack with diagnostics. When a customer says the application “also talks on CAN”, the first check after extraction is whether the CAN code is complete or whether it hands off to a host controller – the answer changes what the rebuild has to deliver.
The Read
Code from FFFE0000h to FFFFFFFFh in 2 KB blocks, E2 data flash as a separate eight-kilobyte area, option bytes from the OFS window, ID code from FFFFFFA0h. Each area is verified against a second read. No block erase, no option change, no ID code change: the unit returns with its contents intact, and checksums taken at intake and handover are part of the report.
Protection, And Why It Does Not Stop This
ID code protection gates boot-mode SCI and the debugging emulator. ROM code protection is a value in block 0 that disables reading and rewriting through a parallel programmer. Start-up program protection pairs blocks 0 to 7 with the alternate 8 to 15. Area protection limits self-programming. The only operation that destroys data is a block erase, and no part of a recovery performs one.
The 64-Pin Constraint On A Rebuild
If the replacement board reuses the same footprint, everything is straightforward. If it moves to a larger package to gain pins, the pin mapping changes and the firmware’s port initialisation no longer matches the hardware. That is the most common way a successful extraction produces an unsuccessful product: the code is right and the board is different.
Deliverables
Intel HEX, E2 binary, option bytes, block map, ID code page, and the peripheral configuration record when a live capture was possible. The record matters more here than on larger parts, because a 64-pin design has fewer spare pins and therefore more multiplexing.
The Bootloader Question
A 128 KB RX24T design with field update capability usually keeps a small bootloader in the lowest blocks of the array and protects it with start-up program protection, so an update can rewrite blocks 0 to 7 from the alternate area at 8 to 15.
Asking whether the product supports field updates changes the read plan. If it does, blocks 0 to 7 get read twice and compared separately, because that region is the one an interrupted update would have damaged – and a unit that failed during an update is a common reason for the call.
Sending A Unit
Note the bus voltage and whether the drive is sensored. A potted or conformally coated board should be described at intake, since the 0.50 mm pitch package changes the access plan.
Start at the services page or the contact form. The 256 KB 64-pin part is R5F524TAADFM; the 100-pin 128 KB part is R5F524T8ADFP.