Ordering the R5F35L30KFF instead of the J-grade part buys a temperature rating, not a different chip. Both carry 64 KB of program ROM 1, 4 KB of RAM and the same 64-pin LQFP, but the K suffix qualifies the die from minus 40 to plus 125 degrees Celsius. On an engine-bay controller that difference decides whether the unit is still in service at all. The R5F35L36JFF extraction note covers the 128 KB sibling with the same rating ladder.
A Grade, Not A Second Mask
Renesas sorted these grades by testing, so the mask set, the memory map and the protection registers are identical. That is good news for recovery: a procedure validated on a J-grade sample transfers without change. It also means the memory type comparison applies directly, and the 26DFE sibling page documents how the same 8 KB data flash behaves on a low-voltage member. What changes on the bench is supply margin, because a part rated for 125 degrees has usually spent years at elevated temperature and its charge retention deserves a second read.
Reading Order On Aged Silicon
Thermal history shows up as weak cells rather than as a dead chip. A long-lived K-grade device may return a clean first pass and disagree on one byte at the second, which is why two reads at a steady rail are part of the routine rather than an optional check. For contrast, an AVR fuse-bit case shows a family where the protection state is a handful of configuration bits; on M16C the equivalent is a word at the top of the array plus a protect bit in the flash control register.
Two Gates, Neither Destructive
A refused session is the worst outcome of a wrong ID on the 30KFF, and that is worth stating plainly. The comparison reads the upper option bytes, the protect setting gates the on-board programmer, and neither action triggers an erase. Unlike a fuse, both can be reprogrammed. So the high-temperature grade keeps its contents through any number of failed connections, which is exactly what a physical capture depends on.
Start from F0000h and read upward: 64 KB of code ends at FFFFFh, where the vectors and the ID bytes also live. Down at 10000h a fixed 16 KB monitor block is present on every group member. The 8 KB data area is split into 4 KB halves between 0E000h and 0FFFFh. Only 4 KB of RAM exists, addressed 00400h to 013FFh, so the heat grade changes no boundary at all.
The Map Is Shared
A steady 5.0 V rail is held throughout both passes on this K-grade sample, because sweeping the supply mid-capture would hide the weak cells we are looking for. Code is read first, then the monitor area, then each data sector, then options. Cycling limits are 1,000 for the program arrays and 10,000 for data storage. The report states whether the two passes agreed on every byte.
The customer receives a merged HEX plus separate binaries, and a note that records the ID and two option bytes, the state of both data sectors, checksums for each region, the capture rail and the outcome of the comparison pass. For a graded part we also state whether a third read was needed. Variable names and comments cannot be reconstructed from the array.
Reporting And Hand-Off
The 32 MHz clock comes from the main oscillator, a sub-clock, or either of two on-chip oscillators, with a PLL available when the application needs full speed.
A watchdog with its own 125 kHz oscillator, a real-time clock, low-voltage detection and power-on reset all remain active at the high-temperature grade.
Nine 16-bit multifunction timer channels plus a 16-bit input-capture and output-compare timer serve the motor and capture functions on this group.
Thermal cycling also stresses the solder joints around the 64-lead body, so a board that fails to boot may simply need reflowing before any readout is attempted.
A K-grade controller should travel unpowered and static-safe, with any thermal history written on the note. If the ID gate will not open, the contact form books the die-level work and the verified dump that follows. That history is not paperwork for its own sake: it tells us whether to plan a third confirming read before releasing the file.